Add m-esr52 at 52.6.0

350 files changed, 38643 insertions, 0 deletions

diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/ReadingListConstants.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/ReadingListConstants.java
new file mode 100644
index 000000000..df603a58e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/ReadingListConstants.java
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background;
+
+import org.mozilla.gecko.AppConstants;
+
+/**
+ * This is in 'background' not 'reading' so that it's still usable even when the
+ * Reading List feature is build-time disabled.
+ */
+public class ReadingListConstants {
+  public static final String GLOBAL_LOG_TAG = "FxReadingList";
+  public static final String USER_AGENT = "Firefox-Android-FxReader/" + AppConstants.MOZ_APP_VERSION + " (" + AppConstants.MOZ_APP_UA_NAME + ")";
+  public static final String DEFAULT_DEV_ENDPOINT = "https://readinglist.dev.mozaws.net/v1/";
+  public static final String DEFAULT_PROD_ENDPOINT = "https://readinglist.services.mozilla.com/v1/";
+
+  public static final String OAUTH_SCOPE_READINGLIST = "readinglist";
+  public static final String AUTH_TOKEN_TYPE = "oauth::" + OAUTH_SCOPE_READINGLIST;
+
+  public static boolean DEBUG = false;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/EditorBranch.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/EditorBranch.java
new file mode 100644
index 000000000..1ead09afa
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/EditorBranch.java
@@ -0,0 +1,82 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common;
+
+import java.util.Set;
+
+import android.content.SharedPreferences;
+import android.content.SharedPreferences.Editor;
+
+public class EditorBranch implements Editor {
+
+  private final String prefix;
+  private Editor editor;
+
+  public EditorBranch(final SharedPreferences prefs, final String prefix) {
+    if (!prefix.endsWith(".")) {
+      throw new IllegalArgumentException("No trailing period in prefix.");
+    }
+    this.prefix = prefix;
+    this.editor = prefs.edit();
+  }
+
+  @Override
+  public void apply() {
+    this.editor.apply();
+  }
+
+  @Override
+  public Editor clear() {
+    this.editor = this.editor.clear();
+    return this;
+  }
+
+  @Override
+  public boolean commit() {
+    return this.editor.commit();
+  }
+
+  @Override
+  public Editor putBoolean(String key, boolean value) {
+    this.editor = this.editor.putBoolean(prefix + key, value);
+    return this;
+  }
+
+  @Override
+  public Editor putFloat(String key, float value) {
+    this.editor = this.editor.putFloat(prefix + key, value);
+    return this;
+  }
+
+  @Override
+  public Editor putInt(String key, int value) {
+    this.editor = this.editor.putInt(prefix + key, value);
+    return this;
+  }
+
+  @Override
+  public Editor putLong(String key, long value) {
+    this.editor = this.editor.putLong(prefix + key, value);
+    return this;
+  }
+
+  @Override
+  public Editor putString(String key, String value) {
+    this.editor = this.editor.putString(prefix + key, value);
+    return this;
+  }
+
+  // Not marking as Override, because Android <= 10 doesn't have
+  // putStringSet. Neither can we implement it.
+  public Editor putStringSet(String key, Set<String> value) {
+    throw new RuntimeException("putStringSet not available.");
+  }
+
+  @Override
+  public Editor remove(String key) {
+    this.editor = this.editor.remove(prefix + key);
+    return this;
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/GlobalConstants.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/GlobalConstants.java
new file mode 100644
index 000000000..d661e62dc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/GlobalConstants.java
@@ -0,0 +1,90 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common;
+
+import org.mozilla.gecko.AppConstants;
+import org.mozilla.gecko.AppConstants.Versions;
+
+/**
+ * Constant values common to all Android services.
+ */
+public class GlobalConstants {
+  public static final String BROWSER_INTENT_PACKAGE = AppConstants.ANDROID_PACKAGE_NAME;
+  public static final String BROWSER_INTENT_CLASS = AppConstants.MOZ_ANDROID_BROWSER_INTENT_CLASS;
+
+  public static final int SHARED_PREFERENCES_MODE = 0;
+
+  // Common time values.
+  public static final long MILLISECONDS_PER_DAY = 24 * 60 * 60 * 1000;
+  public static final long MILLISECONDS_PER_SIX_MONTHS = 180 * MILLISECONDS_PER_DAY;
+
+  // Acceptable cipher suites.
+  /**
+   * We support only a very limited range of strong cipher suites and protocols:
+   * no SSLv3 or TLSv1.0 (if we can), no DHE ciphers that might be vulnerable to Logjam
+   * (https://weakdh.org/), no RC4.
+   *
+   * Backstory: Bug 717691 (we no longer support Android 2.2, so the name
+   * workaround is unnecessary), Bug 1081953, Bug 1061273, Bug 1166839.
+   *
+   * See <http://developer.android.com/reference/javax/net/ssl/SSLSocket.html> for
+   * supported Android versions for each set of protocols and cipher suites.
+   *
+   * Note that currently we need to support connections to Sync 1.1 on Mozilla-hosted infra,
+   * as well as connections to FxA and Sync 1.5 on AWS.
+   *
+   * ELB cipher suites:
+   * <http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGuide/elb-security-policy-table.html>
+   */
+  public static final String[] DEFAULT_CIPHER_SUITES;
+  public static final String[] DEFAULT_PROTOCOLS;
+
+  static {
+    // Prioritize 128 over 256 as a tradeoff between device CPU/battery and the minor
+    // increase in strength.
+    if (Versions.feature20Plus) {
+      DEFAULT_CIPHER_SUITES = new String[]
+          {
+           "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",   // 20+
+           "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",     // 20+
+           "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256",     // 20+
+           "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA",        // 11+
+           "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",     // 20+
+           "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384",     // 20+
+           "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA",        // 11+
+
+           // For Sync 1.1.
+           "TLS_DHE_RSA_WITH_AES_128_CBC_SHA",  // 9+
+           "TLS_RSA_WITH_AES_128_CBC_SHA",      // 9+
+          };
+    } else {
+      DEFAULT_CIPHER_SUITES = new String[]
+          {
+           "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA",        // 11+
+           "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA",      // 11+
+           "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA",        // 11+
+
+           // For Sync 1.1.
+           "TLS_DHE_RSA_WITH_AES_128_CBC_SHA",  // 9+
+           "TLS_RSA_WITH_AES_128_CBC_SHA",      // 9+
+          };
+    }
+
+    if (Versions.feature16Plus) {
+      DEFAULT_PROTOCOLS = new String[]
+          {
+           "TLSv1.2",
+           "TLSv1.1",
+           "TLSv1",             // We would like to remove this, and will do so when we can.
+          };
+    } else {
+      // Fall back to TLSv1 if there's nothing better.
+      DEFAULT_PROTOCOLS = new String[]
+          {
+           "TLSv1",
+          };
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/PrefsBranch.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/PrefsBranch.java
new file mode 100644
index 000000000..78d5f61a1
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/PrefsBranch.java
@@ -0,0 +1,83 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common;
+
+import java.util.Map;
+import java.util.Set;
+
+import android.content.SharedPreferences;
+
+/**
+ * A wrapper around a portion of the SharedPreferences space.
+ */
+public class PrefsBranch implements SharedPreferences {
+  private final SharedPreferences prefs;
+  private final String prefix;                // Including trailing period.
+
+  public PrefsBranch(SharedPreferences prefs, String prefix) {
+    if (!prefix.endsWith(".")) {
+      throw new IllegalArgumentException("No trailing period in prefix.");
+    }
+    this.prefs = prefs;
+    this.prefix = prefix;
+  }
+
+  @Override
+  public boolean contains(String key) {
+    return prefs.contains(prefix + key);
+  }
+
+  @Override
+  public Editor edit() {
+    return new EditorBranch(prefs, prefix);
+  }
+
+  @Override
+  public Map<String, ?> getAll() {
+    // Not implemented. TODO
+    return null;
+  }
+
+  @Override
+  public boolean getBoolean(String key, boolean defValue) {
+    return prefs.getBoolean(prefix + key, defValue);
+  }
+
+  @Override
+  public float getFloat(String key, float defValue) {
+    return prefs.getFloat(prefix + key, defValue);
+  }
+
+  @Override
+  public int getInt(String key, int defValue) {
+    return prefs.getInt(prefix + key, defValue);
+  }
+
+  @Override
+  public long getLong(String key, long defValue) {
+    return prefs.getLong(prefix + key, defValue);
+  }
+
+  @Override
+  public String getString(String key, String defValue) {
+    return prefs.getString(prefix + key, defValue);
+  }
+
+  // Not marking as Override, because Android <= 10 doesn't have
+  // getStringSet. Neither can we implement it.
+  public Set<String> getStringSet(String key, Set<String> defValue) {
+    throw new RuntimeException("getStringSet not available.");
+  }
+
+  @Override
+  public void registerOnSharedPreferenceChangeListener(OnSharedPreferenceChangeListener listener) {
+    prefs.registerOnSharedPreferenceChangeListener(listener);
+  }
+
+  @Override
+  public void unregisterOnSharedPreferenceChangeListener(OnSharedPreferenceChangeListener listener) {
+    prefs.unregisterOnSharedPreferenceChangeListener(listener);
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/Logger.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/Logger.java
new file mode 100644
index 000000000..2575717eb
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/Logger.java
@@ -0,0 +1,232 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log;
+
+import java.io.PrintWriter;
+import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+import org.mozilla.gecko.background.common.GlobalConstants;
+import org.mozilla.gecko.background.common.log.writers.AndroidLevelCachingLogWriter;
+import org.mozilla.gecko.background.common.log.writers.AndroidLogWriter;
+import org.mozilla.gecko.background.common.log.writers.LogWriter;
+import org.mozilla.gecko.background.common.log.writers.PrintLogWriter;
+import org.mozilla.gecko.background.common.log.writers.SimpleTagLogWriter;
+import org.mozilla.gecko.background.common.log.writers.ThreadLocalTagLogWriter;
+
+import android.util.Log;
+
+/**
+ * Logging helper class. Serializes all log operations (by synchronizing).
+ */
+public class Logger {
+  public static final String LOGGER_TAG = "Logger";
+  public static final String DEFAULT_LOG_TAG = "GeckoLogger";
+
+  // For extra debugging.
+  public static boolean LOG_PERSONAL_INFORMATION = false;
+
+  /**
+   * Allow each thread to use its own global log tag. This allows
+   * independent services to log as different sources.
+   *
+   * When your thread sets up logging, it should do something like the following:
+   *
+   *   Logger.setThreadLogTag("MyTag");
+   *
+   * The value is inheritable, so worker threads and such do not need to
+   * set the same log tag as their parent.
+   */
+  private static final InheritableThreadLocal<String> logTag = new InheritableThreadLocal<String>() {
+    @Override
+    protected String initialValue() {
+      return DEFAULT_LOG_TAG;
+    }
+  };
+
+  public static void setThreadLogTag(final String logTag) {
+    Logger.logTag.set(logTag);
+  }
+  public static String getThreadLogTag() {
+    return Logger.logTag.get();
+  }
+
+  /**
+   * Current set of writers to which we will log.
+   * <p>
+   * We want logging to be available while running tests, so we initialize
+   * this set statically.
+   */
+  protected final static Set<LogWriter> logWriters;
+  static {
+    final Set<LogWriter> defaultWriters = Logger.defaultLogWriters();
+    logWriters = new LinkedHashSet<LogWriter>(defaultWriters);
+  }
+
+  /**
+   * Default set of log writers to log to.
+   */
+  public final static Set<LogWriter> defaultLogWriters() {
+    final String processedPackage = GlobalConstants.BROWSER_INTENT_PACKAGE.replace("org.mozilla.", "");
+
+    final Set<LogWriter> defaultLogWriters = new LinkedHashSet<LogWriter>();
+
+    final LogWriter log = new AndroidLogWriter();
+    final LogWriter cache = new AndroidLevelCachingLogWriter(log);
+
+    final LogWriter single = new SimpleTagLogWriter(processedPackage, new ThreadLocalTagLogWriter(Logger.logTag, cache));
+
+    defaultLogWriters.add(single);
+    return defaultLogWriters;
+  }
+
+  public static synchronized void startLoggingTo(LogWriter logWriter) {
+    logWriters.add(logWriter);
+  }
+
+  public static synchronized void startLoggingToWriters(Set<LogWriter> writers) {
+    logWriters.addAll(writers);
+  }
+
+  public static synchronized void stopLoggingTo(LogWriter logWriter) {
+    try {
+      logWriter.close();
+    } catch (Exception e) {
+      Log.e(LOGGER_TAG, "Got exception closing and removing LogWriter " + logWriter + ".", e);
+    }
+    logWriters.remove(logWriter);
+  }
+
+  public static synchronized void stopLoggingToAll() {
+    for (LogWriter logWriter : logWriters) {
+      try {
+        logWriter.close();
+      } catch (Exception e) {
+        Log.e(LOGGER_TAG, "Got exception closing and removing LogWriter " + logWriter + ".", e);
+      }
+    }
+    logWriters.clear();
+  }
+
+  /**
+   * Write to only the default log writers.
+   */
+  public static synchronized void resetLogging() {
+    stopLoggingToAll();
+    logWriters.addAll(Logger.defaultLogWriters());
+  }
+
+  /**
+   * Start writing log output to stdout.
+   * <p>
+   * Use <code>resetLogging</code> to stop logging to stdout.
+   */
+  public static synchronized void startLoggingToConsole() {
+    setThreadLogTag("Test");
+    startLoggingTo(new PrintLogWriter(new PrintWriter(System.out, true)));
+  }
+
+  // Synchronized version for other classes to use.
+  public static synchronized boolean shouldLogVerbose(String logTag) {
+    for (LogWriter logWriter : logWriters) {
+      if (logWriter.shouldLogVerbose(logTag)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  public static void error(String tag, String message) {
+    Logger.error(tag, message, null);
+  }
+
+  public static void warn(String tag, String message) {
+    Logger.warn(tag, message, null);
+  }
+
+  public static void info(String tag, String message) {
+    Logger.info(tag, message, null);
+  }
+
+  public static void debug(String tag, String message) {
+    Logger.debug(tag, message, null);
+  }
+
+  public static void trace(String tag, String message) {
+    Logger.trace(tag, message, null);
+  }
+
+  public static void pii(String tag, String message) {
+    if (LOG_PERSONAL_INFORMATION) {
+      Logger.debug(tag, "$$PII$$: " + message);
+    }
+  }
+
+  public static synchronized void error(String tag, String message, Throwable error) {
+    Iterator<LogWriter> it = logWriters.iterator();
+    while (it.hasNext()) {
+      LogWriter writer = it.next();
+      try {
+        writer.error(tag, message, error);
+      } catch (Exception e) {
+        Log.e(LOGGER_TAG, "Got exception logging; removing LogWriter " + writer + ".", e);
+        it.remove();
+      }
+    }
+  }
+
+  public static synchronized void warn(String tag, String message, Throwable error) {
+    Iterator<LogWriter> it = logWriters.iterator();
+    while (it.hasNext()) {
+      LogWriter writer = it.next();
+      try {
+        writer.warn(tag, message, error);
+      } catch (Exception e) {
+        Log.e(LOGGER_TAG, "Got exception logging; removing LogWriter " + writer + ".", e);
+        it.remove();
+      }
+    }
+  }
+
+  public static synchronized void info(String tag, String message, Throwable error) {
+    Iterator<LogWriter> it = logWriters.iterator();
+    while (it.hasNext()) {
+      LogWriter writer = it.next();
+      try {
+        writer.info(tag, message, error);
+      } catch (Exception e) {
+        Log.e(LOGGER_TAG, "Got exception logging; removing LogWriter " + writer + ".", e);
+        it.remove();
+      }
+    }
+  }
+
+  public static synchronized void debug(String tag, String message, Throwable error) {
+    Iterator<LogWriter> it = logWriters.iterator();
+    while (it.hasNext()) {
+      LogWriter writer = it.next();
+      try {
+        writer.debug(tag, message, error);
+      } catch (Exception e) {
+        Log.e(LOGGER_TAG, "Got exception logging; removing LogWriter " + writer + ".", e);
+        it.remove();
+      }
+    }
+  }
+
+  public static synchronized void trace(String tag, String message, Throwable error) {
+    Iterator<LogWriter> it = logWriters.iterator();
+    while (it.hasNext()) {
+      LogWriter writer = it.next();
+      try {
+        writer.trace(tag, message, error);
+      } catch (Exception e) {
+        Log.e(LOGGER_TAG, "Got exception logging; removing LogWriter " + writer + ".", e);
+        it.remove();
+      }
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/AndroidLevelCachingLogWriter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/AndroidLevelCachingLogWriter.java
new file mode 100644
index 000000000..ac4250a03
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/AndroidLevelCachingLogWriter.java
@@ -0,0 +1,132 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log.writers;
+
+import java.util.IdentityHashMap;
+import java.util.Map;
+
+import android.util.Log;
+
+/**
+ * Make a <code>LogWriter</code> only log when the Android log system says to.
+ */
+public class AndroidLevelCachingLogWriter extends LogWriter {
+  protected final LogWriter inner;
+
+  public AndroidLevelCachingLogWriter(LogWriter inner) {
+    this.inner = inner;
+  }
+
+  // I can't believe we have to implement this ourselves.
+  // These aren't synchronized (and neither are the setters) because
+  // the logging calls themselves are synchronized.
+  private Map<String, Boolean> isErrorLoggable   = new IdentityHashMap<String, Boolean>();
+  private Map<String, Boolean> isWarnLoggable    = new IdentityHashMap<String, Boolean>();
+  private Map<String, Boolean> isInfoLoggable    = new IdentityHashMap<String, Boolean>();
+  private Map<String, Boolean> isDebugLoggable   = new IdentityHashMap<String, Boolean>();
+  private Map<String, Boolean> isVerboseLoggable = new IdentityHashMap<String, Boolean>();
+
+  /**
+   * Empty the caches of log levels.
+   */
+  public void refreshLogLevels() {
+    isErrorLoggable   = new IdentityHashMap<String, Boolean>();
+    isWarnLoggable    = new IdentityHashMap<String, Boolean>();
+    isInfoLoggable    = new IdentityHashMap<String, Boolean>();
+    isDebugLoggable   = new IdentityHashMap<String, Boolean>();
+    isVerboseLoggable = new IdentityHashMap<String, Boolean>();
+  }
+
+  private boolean shouldLogError(String logTag) {
+    Boolean out = isErrorLoggable.get(logTag);
+    if (out != null) {
+      return out;
+    }
+    out = Log.isLoggable(logTag, Log.ERROR);
+    isErrorLoggable.put(logTag, out);
+    return out;
+  }
+
+  private boolean shouldLogWarn(String logTag) {
+    Boolean out = isWarnLoggable.get(logTag);
+    if (out != null) {
+      return out;
+    }
+    out = Log.isLoggable(logTag, Log.WARN);
+    isWarnLoggable.put(logTag, out);
+    return out;
+  }
+
+  private boolean shouldLogInfo(String logTag) {
+    Boolean out = isInfoLoggable.get(logTag);
+    if (out != null) {
+      return out;
+    }
+    out = Log.isLoggable(logTag, Log.INFO);
+    isInfoLoggable.put(logTag, out);
+    return out;
+  }
+
+  private boolean shouldLogDebug(String logTag) {
+    Boolean out = isDebugLoggable.get(logTag);
+    if (out != null) {
+      return out;
+    }
+    out = Log.isLoggable(logTag, Log.DEBUG);
+    isDebugLoggable.put(logTag, out);
+    return out;
+  }
+
+  @Override
+  public boolean shouldLogVerbose(String logTag) {
+    Boolean out = isVerboseLoggable.get(logTag);
+    if (out != null) {
+      return out;
+    }
+    out = Log.isLoggable(logTag, Log.VERBOSE);
+    isVerboseLoggable.put(logTag, out);
+    return out;
+  }
+
+  @Override
+  public void error(String tag, String message, Throwable error) {
+    if (shouldLogError(tag)) {
+      inner.error(tag, message, error);
+    }
+  }
+
+  @Override
+  public void warn(String tag, String message, Throwable error) {
+    if (shouldLogWarn(tag)) {
+      inner.warn(tag, message, error);
+    }
+  }
+
+  @Override
+  public void info(String tag, String message, Throwable error) {
+    if (shouldLogInfo(tag)) {
+      inner.info(tag, message, error);
+    }
+  }
+
+  @Override
+  public void debug(String tag, String message, Throwable error) {
+    if (shouldLogDebug(tag)) {
+      inner.debug(tag, message, error);
+    }
+  }
+
+  @Override
+  public void trace(String tag, String message, Throwable error) {
+    if (shouldLogVerbose(tag)) {
+      inner.trace(tag, message, error);
+    }
+  }
+
+  @Override
+  public void close() {
+    inner.close();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/AndroidLogWriter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/AndroidLogWriter.java
new file mode 100644
index 000000000..9d309844d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/AndroidLogWriter.java
@@ -0,0 +1,46 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log.writers;
+
+import android.util.Log;
+
+/**
+ * Log to the Android log.
+ */
+public class AndroidLogWriter extends LogWriter {
+  @Override
+  public boolean shouldLogVerbose(String logTag) {
+    return true;
+  }
+
+  @Override
+  public void error(String tag, String message, Throwable error) {
+    Log.e(tag, message, error);
+  }
+
+  @Override
+  public void warn(String tag, String message, Throwable error) {
+    Log.w(tag, message, error);
+  }
+
+  @Override
+  public void info(String tag, String message, Throwable error) {
+    Log.i(tag, message, error);
+  }
+
+  @Override
+  public void debug(String tag, String message, Throwable error) {
+    Log.d(tag, message, error);
+  }
+
+  @Override
+  public void trace(String tag, String message, Throwable error) {
+    Log.v(tag, message, error);
+  }
+
+  @Override
+  public void close() {
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/LevelFilteringLogWriter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/LevelFilteringLogWriter.java
new file mode 100644
index 000000000..74c3608c4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/LevelFilteringLogWriter.java
@@ -0,0 +1,67 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log.writers;
+
+import android.util.Log;
+
+/**
+ * A LogWriter that logs only if the message is as important as the specified
+ * level. For example, if the specified level is <code>Log.WARN</code>, only
+ * <code>warn</code> and <code>error</code> will log.
+ */
+public class LevelFilteringLogWriter extends LogWriter {
+  protected final LogWriter inner;
+  protected final int logLevel;
+
+  public LevelFilteringLogWriter(int logLevel, LogWriter inner) {
+    this.inner = inner;
+    this.logLevel = logLevel;
+  }
+
+  @Override
+  public void close() {
+    inner.close();
+  }
+
+  @Override
+  public void error(String tag, String message, Throwable error) {
+    if (logLevel <= Log.ERROR) {
+      inner.error(tag, message, error);
+    }
+  }
+
+  @Override
+  public void warn(String tag, String message, Throwable error) {
+    if (logLevel <= Log.WARN) {
+      inner.warn(tag, message, error);
+    }
+  }
+
+  @Override
+  public void info(String tag, String message, Throwable error) {
+    if (logLevel <= Log.INFO) {
+      inner.info(tag, message, error);
+    }
+  }
+
+  @Override
+  public void debug(String tag, String message, Throwable error) {
+    if (logLevel <= Log.DEBUG) {
+      inner.debug(tag, message, error);
+    }
+  }
+
+  @Override
+  public void trace(String tag, String message, Throwable error) {
+    if (logLevel <= Log.VERBOSE) {
+      inner.trace(tag, message, error);
+    }
+  }
+
+  @Override
+  public boolean shouldLogVerbose(String tag) {
+    return logLevel <= Log.VERBOSE;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/LogWriter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/LogWriter.java
new file mode 100644
index 000000000..acfb09969
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/LogWriter.java
@@ -0,0 +1,29 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log.writers;
+
+/**
+ * An abstract object that logs information in some way.
+ * <p>
+ * Intended to be composed with other log writers, for example a log
+ * writer could make all log entries have the same single log tag, or
+ * could ignore certain log levels, before delegating to an inner log
+ * writer.
+ */
+public abstract class LogWriter {
+  public abstract void error(String tag, String message, Throwable error);
+  public abstract void warn(String tag, String message, Throwable error);
+  public abstract void info(String tag, String message, Throwable error);
+  public abstract void debug(String tag, String message, Throwable error);
+  public abstract void trace(String tag, String message, Throwable error);
+
+  /**
+   * We expect <code>close</code> to be called only by static
+   * synchronized methods in class <code>Logger</code>.
+   */
+  public abstract void close();
+
+  public abstract boolean shouldLogVerbose(String tag);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/PrintLogWriter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/PrintLogWriter.java
new file mode 100644
index 000000000..6e1f63de3
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/PrintLogWriter.java
@@ -0,0 +1,77 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log.writers;
+
+import java.io.PrintWriter;
+
+/**
+ * Log to a <code>PrintWriter</code>.
+ */
+public class PrintLogWriter extends LogWriter {
+  protected final PrintWriter pw;
+  protected boolean closed = false;
+
+  public static final String ERROR   = " :: E :: ";
+  public static final String WARN    = " :: W :: ";
+  public static final String INFO    = " :: I :: ";
+  public static final String DEBUG   = " :: D :: ";
+  public static final String VERBOSE = " :: V :: ";
+
+  public PrintLogWriter(PrintWriter pw) {
+    this.pw = pw;
+  }
+
+  protected void log(String tag, String message, Throwable error) {
+    if (closed) {
+      return;
+    }
+
+    pw.println(tag + message);
+    if (error != null) {
+      error.printStackTrace(pw);
+    }
+  }
+
+  @Override
+  public void error(String tag, String message, Throwable error) {
+    log(tag, ERROR + message, error);
+  }
+
+  @Override
+  public void warn(String tag, String message, Throwable error) {
+    log(tag, WARN + message, error);
+  }
+
+  @Override
+  public void info(String tag, String message, Throwable error) {
+    log(tag, INFO + message, error);
+  }
+
+  @Override
+  public void debug(String tag, String message, Throwable error) {
+    log(tag, DEBUG + message, error);
+  }
+
+  @Override
+  public void trace(String tag, String message, Throwable error) {
+    log(tag, VERBOSE + message, error);
+  }
+
+  @Override
+  public boolean shouldLogVerbose(String tag) {
+    return true;
+  }
+
+  @Override
+  public void close() {
+    if (closed) {
+      return;
+    }
+    if (pw != null) {
+      pw.close();
+    }
+    closed = true;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/SimpleTagLogWriter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/SimpleTagLogWriter.java
new file mode 100644
index 000000000..a17654371
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/SimpleTagLogWriter.java
@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log.writers;
+
+/**
+ * Make a <code>LogWriter</code> only log with a single string tag.
+ */
+public class SimpleTagLogWriter extends TagLogWriter {
+  final String tag;
+  public SimpleTagLogWriter(String tag, LogWriter inner) {
+    super(inner);
+    this.tag = tag;
+  }
+
+  @Override
+  protected String getMainTag() {
+    return tag;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/StringLogWriter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/StringLogWriter.java
new file mode 100644
index 000000000..d6a9f5eb8
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/StringLogWriter.java
@@ -0,0 +1,57 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log.writers;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+public class StringLogWriter extends LogWriter {
+  protected final StringWriter sw;
+  protected final PrintLogWriter inner;
+
+  public StringLogWriter() {
+    sw = new StringWriter();
+    inner = new PrintLogWriter(new PrintWriter(sw));
+  }
+
+  public String toString() {
+    return sw.toString();
+  }
+
+  @Override
+  public boolean shouldLogVerbose(String tag) {
+    return true;
+  }
+
+  @Override
+  public void error(String tag, String message, Throwable error) {
+    inner.error(tag, message, error);
+  }
+
+  @Override
+  public void warn(String tag, String message, Throwable error) {
+    inner.warn(tag, message, error);
+  }
+
+  @Override
+  public void info(String tag, String message, Throwable error) {
+    inner.info(tag, message, error);
+  }
+
+  @Override
+  public void debug(String tag, String message, Throwable error) {
+    inner.debug(tag, message, error);
+  }
+
+  @Override
+  public void trace(String tag, String message, Throwable error) {
+    inner.trace(tag, message, error);
+  }
+
+  @Override
+  public void close() {
+    inner.close();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/TagLogWriter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/TagLogWriter.java
new file mode 100644
index 000000000..fbcd94a91
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/TagLogWriter.java
@@ -0,0 +1,55 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log.writers;
+
+/**
+ * A @link{LogWriter} that logs each message under a parent tag.
+ */
+public abstract class TagLogWriter extends LogWriter {
+
+  protected final LogWriter inner;
+
+  public TagLogWriter(final LogWriter inner) {
+    super();
+    this.inner = inner;
+  }
+
+  protected abstract String getMainTag();
+
+  @Override
+  public void error(String tag, String message, Throwable error) {
+    inner.error(this.getMainTag(), tag + " :: " + message, error);
+  }
+
+  @Override
+  public void warn(String tag, String message, Throwable error) {
+    inner.warn(this.getMainTag(), tag + " :: " + message, error);
+  }
+
+  @Override
+  public void info(String tag, String message, Throwable error) {
+    inner.info(this.getMainTag(), tag + " :: " + message, error);
+  }
+
+  @Override
+  public void debug(String tag, String message, Throwable error) {
+    inner.debug(this.getMainTag(), tag + " :: " + message, error);
+  }
+
+  @Override
+  public void trace(String tag, String message, Throwable error) {
+    inner.trace(this.getMainTag(), tag + " :: " + message, error);
+  }
+
+  @Override
+  public boolean shouldLogVerbose(String tag) {
+    return inner.shouldLogVerbose(this.getMainTag());
+  }
+
+  @Override
+  public void close() {
+    inner.close();
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/ThreadLocalTagLogWriter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/ThreadLocalTagLogWriter.java
new file mode 100644
index 000000000..0c83504a0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/log/writers/ThreadLocalTagLogWriter.java
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.log.writers;
+
+/**
+ * Log with a single global tag… but that tag can be different for each thread.
+ *
+ * Takes a @link{ThreadLocal} as a constructor parameter.
+ */
+public class ThreadLocalTagLogWriter extends TagLogWriter {
+
+  private final ThreadLocal<String> tag;
+
+  public ThreadLocalTagLogWriter(ThreadLocal<String> tag, LogWriter inner) {
+    super(inner);
+    this.tag = tag;
+  }
+
+  @Override
+  protected String getMainTag() {
+    return this.tag.get();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/telemetry/TelemetryWrapper.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/telemetry/TelemetryWrapper.java
new file mode 100644
index 000000000..6639b817d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/common/telemetry/TelemetryWrapper.java
@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.common.telemetry;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+/**
+ * Android Background Services are normally built into Fennec, but can also be
+ * built as a stand-alone APK for rapid local development. The current Telemetry
+ * implementation is coupled to Gecko, and Background Services should not
+ * interact with Gecko directly. To maintain this independence, Background
+ * Services lazily introspects the relevant Telemetry class from the enclosing
+ * package, warning but otherwise ignoring failures during introspection or
+ * invocation.
+ * <p>
+ * It is possible that Background Services will introspect and invoke the
+ * Telemetry implementation while Gecko is not running. In this case, the Fennec
+ * process itself buffers Telemetry events until such time as they can be
+ * flushed to disk and uploaded. <b>There is no guarantee that all Telemetry
+ * events will be uploaded!</b> Depending on the volume of data and the
+ * application lifecycle, Telemetry events may be dropped.
+ */
+public class TelemetryWrapper {
+  private static final String LOG_TAG = TelemetryWrapper.class.getSimpleName();
+
+  // Marking this volatile maintains thread safety cheaply.
+  private static volatile Method mAddToHistogram;
+
+  public static void addToHistogram(String key, int value) {
+    if (mAddToHistogram == null) {
+      try {
+        final Class<?> telemetry = Class.forName("org.mozilla.gecko.Telemetry");
+        mAddToHistogram = telemetry.getMethod("addToHistogram", String.class, int.class);
+      } catch (ClassNotFoundException e) {
+        Logger.warn(LOG_TAG, "org.mozilla.gecko.Telemetry class found!");
+        return;
+      } catch (NoSuchMethodException e) {
+        Logger.warn(LOG_TAG, "org.mozilla.gecko.Telemetry.addToHistogram(String, int) method not found!");
+        return;
+      }
+    }
+
+    if (mAddToHistogram != null) {
+      try {
+        mAddToHistogram.invoke(null, key, value);
+      } catch (IllegalArgumentException | InvocationTargetException | IllegalAccessException e) {
+        Logger.warn(LOG_TAG, "Got exception invoking telemetry!");
+      }
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/db/CursorDumper.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/db/CursorDumper.java
new file mode 100644
index 000000000..bce968b00
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/db/CursorDumper.java
@@ -0,0 +1,99 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.db;
+
+import android.database.Cursor;
+
+/**
+ * A utility for dumping a cursor the debug log.
+ * <p>
+ * <b>For debugging only!</p>
+ */
+public class CursorDumper {
+  protected static String fixedWidth(int width, String s) {
+    if (s == null) {
+      return spaces(width);
+    }
+    int length = s.length();
+    if (width == length) {
+      return s;
+    }
+    if (width > length) {
+      return s + spaces(width - length);
+    }
+    return s.substring(0, width);
+  }
+
+  protected static String spaces(int i) {
+    return "                                     ".substring(0, i);
+  }
+
+  protected static String dashes(int i) {
+    return "-------------------------------------".substring(0, i);
+  }
+
+  /**
+   * Dump a cursor to the debug log, ignoring any log level settings.
+   * <p>
+   * The position in the cursor is maintained. Caller is responsible for opening
+   * and closing cursor.
+   *
+   * @param cursor
+   *          to dump.
+   */
+  public static void dumpCursor(Cursor cursor) {
+    dumpCursor(cursor, 18, "records");
+  }
+
+  /**
+   * Dump a cursor to the debug log, ignoring any log level settings.
+   * <p>
+   * The position in the cursor is maintained. Caller is responsible for opening
+   * and closing cursor.
+   *
+   * @param cursor
+   *          to dump.
+   * @param columnWidth
+   *          how many characters per cursor column.
+   * @param tags
+   *          a descriptor, printed like "(10 tags)", in the header row.
+   */
+  protected static void dumpCursor(Cursor cursor, int columnWidth, String tags) {
+    int originalPosition = cursor.getPosition();
+    try {
+      String[] columnNames = cursor.getColumnNames();
+      int columnCount      = cursor.getColumnCount();
+
+      for (int i = 0; i < columnCount; ++i) {
+        System.out.print(fixedWidth(columnWidth, columnNames[i]) + " | ");
+      }
+      System.out.println("(" + cursor.getCount() + " " + tags + ")");
+      for (int i = 0; i < columnCount; ++i) {
+        System.out.print(dashes(columnWidth) + " | ");
+      }
+      System.out.println("");
+      if (!cursor.moveToFirst()) {
+        System.out.println("EMPTY");
+        return;
+      }
+
+      cursor.moveToFirst();
+      while (!cursor.isAfterLast()) {
+        for (int i = 0; i < columnCount; ++i) {
+          System.out.print(fixedWidth(columnWidth, cursor.getString(i)) + " | ");
+        }
+        System.out.println("");
+        cursor.moveToNext();
+      }
+      for (int i = 0; i < columnCount-1; ++i) {
+        System.out.print(dashes(columnWidth + 3));
+      }
+      System.out.print(dashes(columnWidth + 3 - 1));
+      System.out.println("");
+    } finally {
+      cursor.moveToPosition(originalPosition);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/db/Tab.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/db/Tab.java
new file mode 100644
index 000000000..f38cfdf0e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/db/Tab.java
@@ -0,0 +1,86 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.db;
+
+import org.json.simple.JSONArray;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.db.BrowserContract.Tabs;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.repositories.android.RepoUtils;
+
+import android.content.ContentValues;
+import android.database.Cursor;
+
+// Immutable.
+public class Tab {
+  public final String    title;
+  public final String    icon;
+  public final JSONArray history;
+  public final long      lastUsed;
+
+  public Tab(String title, String icon, JSONArray history, long lastUsed) {
+    this.title    = title;
+    this.icon     = icon;
+    this.history  = history;
+    this.lastUsed = lastUsed;
+  }
+
+  public ContentValues toContentValues(String clientGUID, int position) {
+    ContentValues out = new ContentValues();
+    out.put(BrowserContract.Tabs.POSITION,    position);
+    out.put(BrowserContract.Tabs.CLIENT_GUID, clientGUID);
+
+    out.put(BrowserContract.Tabs.FAVICON,   this.icon);
+    out.put(BrowserContract.Tabs.LAST_USED, this.lastUsed);
+    out.put(BrowserContract.Tabs.TITLE,     this.title);
+    out.put(BrowserContract.Tabs.URL,       (String) this.history.get(0));
+    out.put(BrowserContract.Tabs.HISTORY,   this.history.toJSONString());
+    return out;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (!(o instanceof Tab)) {
+      return false;
+    }
+    final Tab other = (Tab) o;
+
+    if (!RepoUtils.stringsEqual(this.title, other.title)) {
+      return false;
+    }
+    if (!RepoUtils.stringsEqual(this.icon, other.icon)) {
+      return false;
+    }
+
+    if (!(this.lastUsed == other.lastUsed)) {
+      return false;
+    }
+
+    return Utils.sameArrays(this.history, other.history);
+  }
+
+  @Override
+  public int hashCode() {
+    return super.hashCode();
+  }
+
+  /**
+   * Extract a <code>Tab</code> from a cursor row.
+   * <p>
+   * Caller is responsible for creating, positioning, and closing the cursor.
+   *
+   * @param cursor
+   *          to inspect.
+   * @return <code>Tab</code> instance.
+   */
+  public static Tab fromCursor(final Cursor cursor) {
+    final String title = RepoUtils.getStringFromCursor(cursor, Tabs.TITLE);
+    final String icon = RepoUtils.getStringFromCursor(cursor, Tabs.FAVICON);
+    final JSONArray history = RepoUtils.getJSONArrayFromCursor(cursor, Tabs.HISTORY);
+    final long lastUsed = RepoUtils.getLongFromCursor(cursor, Tabs.LAST_USED);
+
+    return new Tab(title, icon, history, lastUsed);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccount20CreateDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccount20CreateDelegate.java
new file mode 100644
index 000000000..98809137f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccount20CreateDelegate.java
@@ -0,0 +1,52 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.Utils;
+
+import java.io.UnsupportedEncodingException;
+import java.security.GeneralSecurityException;
+
+public class FxAccount20CreateDelegate {
+  protected final byte[] emailUTF8;
+  protected final byte[] authPW;
+  protected final boolean preVerified;
+
+  /**
+   * Make a new "create account" delegate.
+   *
+   * @param emailUTF8
+   *          email as UTF-8 bytes.
+   * @param quickStretchedPW
+   *          quick stretched password as bytes.
+   * @param preVerified
+   *          true if account should be marked already verified; only effective
+   *          for non-production auth servers.
+   * @throws UnsupportedEncodingException
+   * @throws GeneralSecurityException
+   */
+  public FxAccount20CreateDelegate(byte[] emailUTF8, byte[] quickStretchedPW, boolean preVerified) throws UnsupportedEncodingException, GeneralSecurityException {
+    this.emailUTF8 = emailUTF8;
+    this.authPW = FxAccountUtils.generateAuthPW(quickStretchedPW);
+    this.preVerified = preVerified;
+  }
+
+  public ExtendedJSONObject getCreateBody() throws FxAccountClientException {
+    final ExtendedJSONObject body = new ExtendedJSONObject();
+    try {
+      body.put("email", new String(emailUTF8, "UTF-8"));
+      body.put("authPW", Utils.byte2Hex(authPW));
+      if (preVerified) {
+        // Production endpoints do not allow preVerified; this assumes we only
+        // set it when it's okay to send it.
+        body.put("preVerified", preVerified);
+      }
+      return body;
+    } catch (UnsupportedEncodingException e) {
+      throw new FxAccountClientException(e);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccount20LoginDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccount20LoginDelegate.java
new file mode 100644
index 000000000..0266a6eab
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccount20LoginDelegate.java
@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.Utils;
+
+import java.io.UnsupportedEncodingException;
+import java.security.GeneralSecurityException;
+
+/**
+ * An abstraction around providing an email and authorization token to the auth
+ * server.
+ */
+public class FxAccount20LoginDelegate {
+  protected final byte[] emailUTF8;
+  protected final byte[] authPW;
+
+  public FxAccount20LoginDelegate(byte[] emailUTF8, byte[] quickStretchedPW) throws UnsupportedEncodingException, GeneralSecurityException {
+    this.emailUTF8 = emailUTF8;
+    this.authPW = FxAccountUtils.generateAuthPW(quickStretchedPW);
+  }
+
+  public ExtendedJSONObject getCreateBody() throws FxAccountClientException {
+    final ExtendedJSONObject body = new ExtendedJSONObject();
+    try {
+      body.put("email", new String(emailUTF8, "UTF-8"));
+      body.put("authPW", Utils.byte2Hex(authPW));
+      return body;
+    } catch (UnsupportedEncodingException e) {
+      throw new FxAccountClientException(e);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountClient.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountClient.java
new file mode 100644
index 000000000..ed959ff0e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountClient.java
@@ -0,0 +1,24 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import org.mozilla.gecko.background.fxa.FxAccountClient20.AccountStatusResponse;
+import org.mozilla.gecko.background.fxa.FxAccountClient20.RecoveryEmailStatusResponse;
+import org.mozilla.gecko.background.fxa.FxAccountClient20.RequestDelegate;
+import org.mozilla.gecko.background.fxa.FxAccountClient20.TwoKeys;
+import org.mozilla.gecko.fxa.FxAccountDevice;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+import java.util.List;
+
+public interface FxAccountClient {
+  public void accountStatus(String uid, RequestDelegate<AccountStatusResponse> requestDelegate);
+  public void recoveryEmailStatus(byte[] sessionToken, RequestDelegate<RecoveryEmailStatusResponse> requestDelegate);
+  public void keys(byte[] keyFetchToken, RequestDelegate<TwoKeys> requestDelegate);
+  public void sign(byte[] sessionToken, ExtendedJSONObject publicKey, long certificateDurationInMilliseconds, RequestDelegate<String> requestDelegate);
+  public void registerOrUpdateDevice(byte[] sessionToken, FxAccountDevice device, RequestDelegate<FxAccountDevice> requestDelegate);
+  public void deviceList(byte[] sessionToken, RequestDelegate<FxAccountDevice[]> requestDelegate);
+  public void notifyDevices(byte[] sessionToken, List<String> deviceIds, ExtendedJSONObject payload, Long TTL, RequestDelegate<ExtendedJSONObject> requestDelegate);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountClient20.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountClient20.java
new file mode 100644
index 000000000..596f4525e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountClient20.java
@@ -0,0 +1,914 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import android.support.annotation.NonNull;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountClientException.FxAccountClientMalformedResponseException;
+import org.mozilla.gecko.background.fxa.FxAccountClientException.FxAccountClientRemoteException;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.Locales;
+import org.mozilla.gecko.fxa.FxAccountDevice;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.crypto.HKDF;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.BaseResource;
+import org.mozilla.gecko.sync.net.BaseResourceDelegate;
+import org.mozilla.gecko.sync.net.HawkAuthHeaderProvider;
+import org.mozilla.gecko.sync.net.Resource;
+import org.mozilla.gecko.sync.net.SyncResponse;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URLEncoder;
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.Executor;
+
+import javax.crypto.Mac;
+
+import ch.boye.httpclientandroidlib.HttpEntity;
+import ch.boye.httpclientandroidlib.HttpHeaders;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.ClientProtocolException;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+
+/**
+ * An HTTP client for talking to an FxAccount server.
+ * <p>
+ * <p>
+ * The delegate structure used is a little different from the rest of the code
+ * base. We add a <code>RequestDelegate</code> layer that processes a typed
+ * value extracted from the body of a successful response.
+ */
+public class FxAccountClient20 implements FxAccountClient {
+  protected static final String LOG_TAG = FxAccountClient20.class.getSimpleName();
+
+  protected static final String ACCEPT_HEADER = "application/json;charset=utf-8";
+
+  public static final String JSON_KEY_EMAIL = "email";
+  public static final String JSON_KEY_KEYFETCHTOKEN = "keyFetchToken";
+  public static final String JSON_KEY_SESSIONTOKEN = "sessionToken";
+  public static final String JSON_KEY_UID = "uid";
+  public static final String JSON_KEY_VERIFIED = "verified";
+  public static final String JSON_KEY_ERROR = "error";
+  public static final String JSON_KEY_MESSAGE = "message";
+  public static final String JSON_KEY_INFO = "info";
+  public static final String JSON_KEY_CODE = "code";
+  public static final String JSON_KEY_ERRNO = "errno";
+  public static final String JSON_KEY_EXISTS = "exists";
+
+  protected static final String[] requiredErrorStringFields = { JSON_KEY_ERROR, JSON_KEY_MESSAGE, JSON_KEY_INFO };
+  protected static final String[] requiredErrorLongFields = { JSON_KEY_CODE, JSON_KEY_ERRNO };
+
+  /**
+   * The server's URI.
+   * <p>
+   * We assume throughout that this ends with a trailing slash (and guarantee as
+   * much in the constructor).
+   */
+  protected final String serverURI;
+
+  protected final Executor executor;
+
+  public FxAccountClient20(String serverURI, Executor executor) {
+    if (serverURI == null) {
+      throw new IllegalArgumentException("Must provide a server URI.");
+    }
+    if (executor == null) {
+      throw new IllegalArgumentException("Must provide a non-null executor.");
+    }
+    this.serverURI = serverURI.endsWith("/") ? serverURI : serverURI + "/";
+    if (!this.serverURI.endsWith("/")) {
+      throw new IllegalArgumentException("Constructed serverURI must end with a trailing slash: " + this.serverURI);
+    }
+    this.executor = executor;
+  }
+
+  protected BaseResource getBaseResource(String path, Map<String, String> queryParameters) throws UnsupportedEncodingException, URISyntaxException {
+    if (queryParameters == null || queryParameters.isEmpty()) {
+      return getBaseResource(path);
+    }
+    final String[] array = new String[2 * queryParameters.size()];
+    int i = 0;
+    for (Entry<String, String> entry : queryParameters.entrySet()) {
+      array[i++] = entry.getKey();
+      array[i++] = entry.getValue();
+    }
+    return getBaseResource(path, array);
+  }
+
+  /**
+   * Create <code>BaseResource</code>, encoding query parameters carefully.
+   * <p>
+   * This is equivalent to <code>android.net.Uri.Builder</code>, which is not
+   * present in our JUnit 4 tests.
+   *
+   * @param path fragment.
+   * @param queryParameters list of key/value query parameter pairs.  Must be even length!
+   * @return <code>BaseResource<instance>
+   * @throws URISyntaxException
+   * @throws UnsupportedEncodingException
+   */
+  protected BaseResource getBaseResource(String path, String... queryParameters) throws URISyntaxException, UnsupportedEncodingException {
+    final StringBuilder sb = new StringBuilder(serverURI);
+    sb.append(path);
+    if (queryParameters != null) {
+      int i = 0;
+      while (i < queryParameters.length) {
+        sb.append(i > 0 ? "&" : "?");
+        final String key = queryParameters[i++];
+        final String val = queryParameters[i++];
+        sb.append(URLEncoder.encode(key, "UTF-8"));
+        sb.append("=");
+        sb.append(URLEncoder.encode(val, "UTF-8"));
+      }
+    }
+    return new BaseResource(new URI(sb.toString()));
+  }
+
+  /**
+   * Process a typed value extracted from a successful response (in an
+   * endpoint-dependent way).
+   */
+  public interface RequestDelegate<T> {
+    public void handleError(Exception e);
+    public void handleFailure(FxAccountClientRemoteException e);
+    public void handleSuccess(T result);
+  }
+
+  /**
+   * Thin container for two cryptographic keys.
+   */
+  public static class TwoKeys {
+    public final byte[] kA;
+    public final byte[] wrapkB;
+    public TwoKeys(byte[] kA, byte[] wrapkB) {
+      this.kA = kA;
+      this.wrapkB = wrapkB;
+    }
+  }
+
+  protected <T> void invokeHandleError(final RequestDelegate<T> delegate, final Exception e) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        delegate.handleError(e);
+      }
+    });
+  }
+
+  enum ResponseType {
+    JSON_ARRAY,
+    JSON_OBJECT
+  }
+
+  /**
+   * Translate resource callbacks into request callbacks invoked on the provided
+   * executor.
+   * <p>
+   * Override <code>handleSuccess</code> to parse the body of the resource
+   * request and call the request callback. <code>handleSuccess</code> is
+   * invoked via the executor, so you don't need to delegate further.
+   */
+  protected abstract class ResourceDelegate<T> extends BaseResourceDelegate {
+
+    protected void handleSuccess(final int status, HttpResponse response, final ExtendedJSONObject body) throws Exception {
+      throw new UnsupportedOperationException();
+    }
+
+    protected void handleSuccess(final int status, HttpResponse response, final JSONArray body) throws Exception {
+      throw new UnsupportedOperationException();
+    }
+
+    protected final RequestDelegate<T> delegate;
+
+    protected final byte[] tokenId;
+    protected final byte[] reqHMACKey;
+    protected final SkewHandler skewHandler;
+    protected final ResponseType responseType;
+
+    /**
+     * Create a delegate for an un-authenticated resource.
+     */
+    public ResourceDelegate(final Resource resource, final RequestDelegate<T> delegate, ResponseType responseType) {
+      this(resource, delegate, responseType, null, null);
+    }
+
+    /**
+     * Create a delegate for a Hawk-authenticated resource.
+     * <p>
+     * Every Hawk request that encloses an entity (PATCH, POST, and PUT) will
+     * include the payload verification hash.
+     */
+    public ResourceDelegate(final Resource resource, final RequestDelegate<T> delegate, ResponseType responseType, final byte[] tokenId, final byte[] reqHMACKey) {
+      super(resource);
+      this.delegate = delegate;
+      this.reqHMACKey = reqHMACKey;
+      this.tokenId = tokenId;
+      this.skewHandler = SkewHandler.getSkewHandlerForResource(resource);
+      this.responseType = responseType;
+    }
+
+    @Override
+    public AuthHeaderProvider getAuthHeaderProvider() {
+      if (tokenId != null && reqHMACKey != null) {
+        // We always include the payload verification hash for FxA Hawk-authenticated requests.
+        final boolean includePayloadVerificationHash = true;
+        return new HawkAuthHeaderProvider(Utils.byte2Hex(tokenId), reqHMACKey, includePayloadVerificationHash, skewHandler.getSkewInSeconds());
+      }
+      return super.getAuthHeaderProvider();
+    }
+
+    @Override
+    public String getUserAgent() {
+      return FxAccountConstants.USER_AGENT;
+    }
+
+    @Override
+    public void handleHttpResponse(HttpResponse response) {
+      try {
+        final int status = validateResponse(response);
+        skewHandler.updateSkew(response, now());
+        invokeHandleSuccess(status, response);
+      } catch (FxAccountClientRemoteException e) {
+        if (!skewHandler.updateSkew(response, now())) {
+          // If we couldn't update skew, but we got a failure, let's try clearing the skew.
+          skewHandler.resetSkew();
+        }
+        invokeHandleFailure(e);
+      }
+    }
+
+    protected void invokeHandleFailure(final FxAccountClientRemoteException e) {
+      executor.execute(new Runnable() {
+        @Override
+        public void run() {
+          delegate.handleFailure(e);
+        }
+      });
+    }
+
+    protected void invokeHandleSuccess(final int status, final HttpResponse response) {
+      executor.execute(new Runnable() {
+        @Override
+        public void run() {
+          try {
+            SyncResponse syncResponse = new SyncResponse(response);
+            if (responseType == ResponseType.JSON_ARRAY) {
+              JSONArray body = syncResponse.jsonArrayBody();
+              ResourceDelegate.this.handleSuccess(status, response, body);
+            } else {
+              ExtendedJSONObject body = syncResponse.jsonObjectBody();
+              ResourceDelegate.this.handleSuccess(status, response, body);
+            }
+          } catch (Exception e) {
+            delegate.handleError(e);
+          }
+        }
+      });
+    }
+
+    @Override
+    public void handleHttpProtocolException(final ClientProtocolException e) {
+      invokeHandleError(delegate, e);
+    }
+
+    @Override
+    public void handleHttpIOException(IOException e) {
+      invokeHandleError(delegate, e);
+    }
+
+    @Override
+    public void handleTransportException(GeneralSecurityException e) {
+      invokeHandleError(delegate, e);
+    }
+
+    @Override
+    public void addHeaders(HttpRequestBase request, DefaultHttpClient client) {
+      super.addHeaders(request, client);
+
+      // The basics.
+      final Locale locale = Locale.getDefault();
+      request.addHeader(HttpHeaders.ACCEPT_LANGUAGE, Locales.getLanguageTag(locale));
+      request.addHeader(HttpHeaders.ACCEPT, ACCEPT_HEADER);
+    }
+  }
+
+  protected <T> void post(BaseResource resource, final ExtendedJSONObject requestBody) {
+    if (requestBody == null) {
+      resource.post((HttpEntity) null);
+    } else {
+      resource.post(requestBody);
+    }
+  }
+
+  @SuppressWarnings("static-method")
+  public long now() {
+    return System.currentTimeMillis();
+  }
+
+  /**
+   * Intepret a response from the auth server.
+   * <p>
+   * Throw an appropriate exception on errors; otherwise, return the response's
+   * status code.
+   *
+   * @return response's HTTP status code.
+   * @throws FxAccountClientException
+   */
+  public static int validateResponse(HttpResponse response) throws FxAccountClientRemoteException {
+    final int status = response.getStatusLine().getStatusCode();
+    if (status == 200) {
+      return status;
+    }
+    int code;
+    int errno;
+    String error;
+    String message;
+    String info;
+    ExtendedJSONObject body;
+    try {
+      body = new SyncStorageResponse(response).jsonObjectBody();
+      body.throwIfFieldsMissingOrMisTyped(requiredErrorStringFields, String.class);
+      body.throwIfFieldsMissingOrMisTyped(requiredErrorLongFields, Long.class);
+      code = body.getLong(JSON_KEY_CODE).intValue();
+      errno = body.getLong(JSON_KEY_ERRNO).intValue();
+      error = body.getString(JSON_KEY_ERROR);
+      message = body.getString(JSON_KEY_MESSAGE);
+      info = body.getString(JSON_KEY_INFO);
+    } catch (Exception e) {
+      throw new FxAccountClientMalformedResponseException(response);
+    }
+    throw new FxAccountClientRemoteException(response, code, errno, error, message, info, body);
+  }
+
+  /**
+   * Don't call this directly. Use <code>unbundleBody</code> instead.
+   */
+  protected void unbundleBytes(byte[] bundleBytes, byte[] respHMACKey, byte[] respXORKey, byte[]... rest)
+      throws InvalidKeyException, NoSuchAlgorithmException, FxAccountClientException {
+    if (bundleBytes.length < 32) {
+      throw new IllegalArgumentException("input bundle must include HMAC");
+    }
+    int len = respXORKey.length;
+    if (bundleBytes.length != len + 32) {
+      throw new IllegalArgumentException("input bundle and XOR key with HMAC have different lengths");
+    }
+    int left = len;
+    for (byte[] array : rest) {
+      left -= array.length;
+    }
+    if (left != 0) {
+      throw new IllegalArgumentException("XOR key and total output arrays have different lengths");
+    }
+
+    byte[] ciphertext = new byte[len];
+    byte[] HMAC = new byte[32];
+    System.arraycopy(bundleBytes, 0, ciphertext, 0, len);
+    System.arraycopy(bundleBytes, len, HMAC, 0, 32);
+
+    Mac hmacHasher = HKDF.makeHMACHasher(respHMACKey);
+    byte[] computedHMAC = hmacHasher.doFinal(ciphertext);
+    if (!Arrays.equals(computedHMAC, HMAC)) {
+      throw new FxAccountClientException("Bad message HMAC");
+    }
+
+    int offset = 0;
+    for (byte[] array : rest) {
+      for (int i = 0; i < array.length; i++) {
+        array[i] = (byte) (respXORKey[offset + i] ^ ciphertext[offset + i]);
+      }
+      offset += array.length;
+    }
+  }
+
+  protected void unbundleBody(ExtendedJSONObject body, byte[] requestKey, byte[] ctxInfo, byte[]... rest) throws Exception {
+    int length = 0;
+    for (byte[] array : rest) {
+      length += array.length;
+    }
+
+    if (body == null) {
+      throw new FxAccountClientException("body must be non-null");
+    }
+    String bundle = body.getString("bundle");
+    if (bundle == null) {
+      throw new FxAccountClientException("bundle must be a non-null string");
+    }
+    byte[] bundleBytes = Utils.hex2Byte(bundle);
+
+    final byte[] respHMACKey = new byte[32];
+    final byte[] respXORKey = new byte[length];
+    HKDF.deriveMany(requestKey, new byte[0], ctxInfo, respHMACKey, respXORKey);
+    unbundleBytes(bundleBytes, respHMACKey, respXORKey, rest);
+  }
+
+  public void keys(byte[] keyFetchToken, final RequestDelegate<TwoKeys> delegate) {
+    final byte[] tokenId = new byte[32];
+    final byte[] reqHMACKey = new byte[32];
+    final byte[] requestKey = new byte[32];
+    try {
+      HKDF.deriveMany(keyFetchToken, new byte[0], FxAccountUtils.KW("keyFetchToken"), tokenId, reqHMACKey, requestKey);
+    } catch (Exception e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    BaseResource resource;
+    try {
+      resource = getBaseResource("account/keys");
+    } catch (URISyntaxException | UnsupportedEncodingException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<TwoKeys>(resource, delegate, ResponseType.JSON_OBJECT, tokenId, reqHMACKey) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) throws Exception {
+        byte[] kA = new byte[FxAccountUtils.CRYPTO_KEY_LENGTH_BYTES];
+        byte[] wrapkB = new byte[FxAccountUtils.CRYPTO_KEY_LENGTH_BYTES];
+        unbundleBody(body, requestKey, FxAccountUtils.KW("account/keys"), kA, wrapkB);
+        delegate.handleSuccess(new TwoKeys(kA, wrapkB));
+      }
+    };
+    resource.get();
+  }
+
+  /**
+   * Thin container for account status response.
+   */
+  public static class AccountStatusResponse {
+    public final boolean exists;
+    public AccountStatusResponse(boolean exists) {
+      this.exists = exists;
+    }
+  }
+
+  /**
+   * Query the account status of an account given a uid.
+   *
+   * @param uid to query.
+   * @param delegate to invoke callbacks.
+   */
+  public void accountStatus(String uid, final RequestDelegate<AccountStatusResponse> delegate) {
+    final BaseResource resource;
+    try {
+      final Map<String, String> params = new HashMap<>(1);
+      params.put("uid", uid);
+      resource = getBaseResource("account/status", params);
+    } catch (URISyntaxException | UnsupportedEncodingException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<AccountStatusResponse>(resource, delegate, ResponseType.JSON_OBJECT) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) throws Exception {
+        boolean exists = body.getBoolean(JSON_KEY_EXISTS);
+        delegate.handleSuccess(new AccountStatusResponse(exists));
+      }
+    };
+    resource.get();
+  }
+
+  /**
+   * Thin container for recovery email status response.
+   */
+  public static class RecoveryEmailStatusResponse {
+    public final String email;
+    public final boolean verified;
+    public RecoveryEmailStatusResponse(String email, boolean verified) {
+      this.email = email;
+      this.verified = verified;
+    }
+  }
+
+  /**
+   * Query the recovery email status of an account given a valid session token.
+   * <p>
+   * This API is a little odd: the auth server returns the email and
+   * verification state of the account that corresponds to the (opaque) session
+   * token. It might fail if the session token is unknown (or invalid, or
+   * revoked).
+   *
+   * @param sessionToken
+   *          to query.
+   * @param delegate
+   *          to invoke callbacks.
+   */
+  public void recoveryEmailStatus(byte[] sessionToken, final RequestDelegate<RecoveryEmailStatusResponse> delegate) {
+    final byte[] tokenId = new byte[32];
+    final byte[] reqHMACKey = new byte[32];
+    final byte[] requestKey = new byte[32];
+    try {
+      HKDF.deriveMany(sessionToken, new byte[0], FxAccountUtils.KW("sessionToken"), tokenId, reqHMACKey, requestKey);
+    } catch (Exception e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    BaseResource resource;
+    try {
+      resource = getBaseResource("recovery_email/status");
+    } catch (URISyntaxException | UnsupportedEncodingException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<RecoveryEmailStatusResponse>(resource, delegate, ResponseType.JSON_OBJECT, tokenId, reqHMACKey) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) throws Exception {
+        String[] requiredStringFields = new String[] { JSON_KEY_EMAIL };
+        body.throwIfFieldsMissingOrMisTyped(requiredStringFields, String.class);
+        String email = body.getString(JSON_KEY_EMAIL);
+        Boolean verified = body.getBoolean(JSON_KEY_VERIFIED);
+        delegate.handleSuccess(new RecoveryEmailStatusResponse(email, verified));
+      }
+    };
+    resource.get();
+  }
+
+  @SuppressWarnings("unchecked")
+  public void sign(final byte[] sessionToken, final ExtendedJSONObject publicKey, long durationInMilliseconds, final RequestDelegate<String> delegate) {
+    final ExtendedJSONObject body = new ExtendedJSONObject();
+    body.put("publicKey", publicKey);
+    body.put("duration", durationInMilliseconds);
+
+    final byte[] tokenId = new byte[32];
+    final byte[] reqHMACKey = new byte[32];
+    try {
+      HKDF.deriveMany(sessionToken, new byte[0], FxAccountUtils.KW("sessionToken"), tokenId, reqHMACKey);
+    } catch (Exception e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    BaseResource resource;
+    try {
+      resource = getBaseResource("certificate/sign");
+    } catch (URISyntaxException | UnsupportedEncodingException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<String>(resource, delegate, ResponseType.JSON_OBJECT, tokenId, reqHMACKey) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) throws Exception {
+        String cert = body.getString("cert");
+        if (cert == null) {
+          delegate.handleError(new FxAccountClientException("cert must be a non-null string"));
+          return;
+        }
+        delegate.handleSuccess(cert);
+      }
+    };
+    post(resource, body);
+  }
+
+  protected static final String[] LOGIN_RESPONSE_REQUIRED_STRING_FIELDS = new String[] { JSON_KEY_UID, JSON_KEY_SESSIONTOKEN };
+  protected static final String[] LOGIN_RESPONSE_REQUIRED_STRING_FIELDS_KEYS = new String[] { JSON_KEY_UID, JSON_KEY_SESSIONTOKEN, JSON_KEY_KEYFETCHTOKEN, };
+  protected static final String[] LOGIN_RESPONSE_REQUIRED_BOOLEAN_FIELDS = new String[] { JSON_KEY_VERIFIED };
+
+  /**
+   * Thin container for login response.
+   * <p>
+   * The <code>remoteEmail</code> field is the email address as normalized by the
+   * server, and is <b>not necessarily</b> the email address delivered to the
+   * <code>login</code> or <code>create</code> call.
+   */
+  public static class LoginResponse {
+    public final String remoteEmail;
+    public final String uid;
+    public final byte[] sessionToken;
+    public final boolean verified;
+    public final byte[] keyFetchToken;
+
+    public LoginResponse(String remoteEmail, String uid, boolean verified, byte[] sessionToken, byte[] keyFetchToken) {
+      this.remoteEmail = remoteEmail;
+      this.uid = uid;
+      this.verified = verified;
+      this.sessionToken = sessionToken;
+      this.keyFetchToken = keyFetchToken;
+    }
+  }
+
+  // Public for testing only; prefer login and loginAndGetKeys (without boolean parameter).
+  public void login(final byte[] emailUTF8, final byte[] quickStretchedPW, final boolean getKeys,
+                    final Map<String, String> queryParameters,
+                    final RequestDelegate<LoginResponse> delegate) {
+    final BaseResource resource;
+    final ExtendedJSONObject body;
+    try {
+      final String path = "account/login";
+      final Map<String, String> modifiedParameters = new HashMap<>();
+      if (queryParameters != null) {
+        modifiedParameters.putAll(queryParameters);
+      }
+      if (getKeys) {
+        modifiedParameters.put("keys", "true");
+      }
+      resource = getBaseResource(path, modifiedParameters);
+      body = new FxAccount20LoginDelegate(emailUTF8, quickStretchedPW).getCreateBody();
+    } catch (Exception e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<LoginResponse>(resource, delegate, ResponseType.JSON_OBJECT) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response,  ExtendedJSONObject body) throws Exception {
+        final String[] requiredStringFields = getKeys ? LOGIN_RESPONSE_REQUIRED_STRING_FIELDS_KEYS : LOGIN_RESPONSE_REQUIRED_STRING_FIELDS;
+        body.throwIfFieldsMissingOrMisTyped(requiredStringFields, String.class);
+
+        final String[] requiredBooleanFields = LOGIN_RESPONSE_REQUIRED_BOOLEAN_FIELDS;
+        body.throwIfFieldsMissingOrMisTyped(requiredBooleanFields, Boolean.class);
+
+        String uid = body.getString(JSON_KEY_UID);
+        boolean verified = body.getBoolean(JSON_KEY_VERIFIED);
+        byte[] sessionToken = Utils.hex2Byte(body.getString(JSON_KEY_SESSIONTOKEN));
+        byte[] keyFetchToken = null;
+        if (getKeys) {
+          keyFetchToken = Utils.hex2Byte(body.getString(JSON_KEY_KEYFETCHTOKEN));
+        }
+        LoginResponse loginResponse = new LoginResponse(new String(emailUTF8, "UTF-8"), uid, verified, sessionToken, keyFetchToken);
+
+        delegate.handleSuccess(loginResponse);
+      }
+    };
+
+    post(resource, body);
+  }
+
+  public void createAccount(final byte[] emailUTF8, final byte[] quickStretchedPW,
+                            final boolean getKeys,
+                            final boolean preVerified,
+                            final Map<String, String> queryParameters,
+                            final RequestDelegate<LoginResponse> delegate) {
+    final BaseResource resource;
+    final ExtendedJSONObject body;
+    try {
+      final String path = "account/create";
+      final Map<String, String> modifiedParameters = new HashMap<>();
+      if (queryParameters != null) {
+        modifiedParameters.putAll(queryParameters);
+      }
+      if (getKeys) {
+        modifiedParameters.put("keys", "true");
+      }
+      resource = getBaseResource(path, modifiedParameters);
+      body = new FxAccount20CreateDelegate(emailUTF8, quickStretchedPW, preVerified).getCreateBody();
+    } catch (Exception e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    // This is very similar to login, except verified is not required.
+    resource.delegate = new ResourceDelegate<LoginResponse>(resource, delegate, ResponseType.JSON_OBJECT) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) throws Exception {
+        final String[] requiredStringFields = getKeys ? LOGIN_RESPONSE_REQUIRED_STRING_FIELDS_KEYS : LOGIN_RESPONSE_REQUIRED_STRING_FIELDS;
+        body.throwIfFieldsMissingOrMisTyped(requiredStringFields, String.class);
+
+        String uid = body.getString(JSON_KEY_UID);
+        boolean verified = false; // In production, we're definitely not verified immediately upon creation.
+        Boolean tempVerified = body.getBoolean(JSON_KEY_VERIFIED);
+        if (tempVerified != null) {
+          verified = tempVerified;
+        }
+        byte[] sessionToken = Utils.hex2Byte(body.getString(JSON_KEY_SESSIONTOKEN));
+        byte[] keyFetchToken = null;
+        if (getKeys) {
+          keyFetchToken = Utils.hex2Byte(body.getString(JSON_KEY_KEYFETCHTOKEN));
+        }
+        LoginResponse loginResponse = new LoginResponse(new String(emailUTF8, "UTF-8"), uid, verified, sessionToken, keyFetchToken);
+
+        delegate.handleSuccess(loginResponse);
+      }
+    };
+
+    post(resource, body);
+  }
+
+  /**
+   * We want users to be able to enter their email address case-insensitively.
+   * We stretch the password locally using the email address as a salt, to make
+   * dictionary attacks more expensive. This means that a client with a
+   * case-differing email address is unable to produce the correct
+   * authorization, even though it knows the password. In this case, the server
+   * returns the email that the account was created with, so that the client can
+   * re-stretch the password locally with the correct email salt. This version
+   * of <code>login</code> retries at most one time with a server provided email
+   * address.
+   * <p>
+   * Be aware that consumers will not see the initial error response from the
+   * server providing an alternate email (if there is one).
+   *
+   * @param emailUTF8
+   *          user entered email address.
+   * @param stretcher
+   *          delegate to stretch and re-stretch password.
+   * @param getKeys
+   *          true if a <code>keyFetchToken</code> should be returned (in
+   *          addition to the standard <code>sessionToken</code>).
+   * @param queryParameters
+   * @param delegate
+   *          to invoke callbacks.
+   */
+  public void login(final byte[] emailUTF8, final PasswordStretcher stretcher, final boolean getKeys,
+                    final Map<String, String> queryParameters,
+                    final RequestDelegate<LoginResponse> delegate) {
+    byte[] quickStretchedPW;
+    try {
+      FxAccountUtils.pii(LOG_TAG, "Trying user provided email: '" + new String(emailUTF8, "UTF-8") + "'" );
+      quickStretchedPW = stretcher.getQuickStretchedPW(emailUTF8);
+    } catch (Exception e) {
+      delegate.handleError(e);
+      return;
+    }
+
+    this.login(emailUTF8, quickStretchedPW, getKeys, queryParameters, new RequestDelegate<LoginResponse>() {
+      @Override
+      public void handleSuccess(LoginResponse result) {
+        delegate.handleSuccess(result);
+      }
+
+      @Override
+      public void handleError(Exception e) {
+        delegate.handleError(e);
+      }
+
+      @Override
+      public void handleFailure(FxAccountClientRemoteException e) {
+        String alternateEmail = e.body.getString(JSON_KEY_EMAIL);
+        if (!e.isBadEmailCase() || alternateEmail == null) {
+          delegate.handleFailure(e);
+          return;
+        };
+
+        Logger.info(LOG_TAG, "Server returned alternate email; retrying login with provided email.");
+        FxAccountUtils.pii(LOG_TAG, "Trying server provided email: '" + alternateEmail + "'" );
+
+        try {
+          // Nota bene: this is not recursive, since we call the fixed password
+          // signature here, which invokes a non-retrying version.
+          byte[] alternateEmailUTF8 = alternateEmail.getBytes("UTF-8");
+          byte[] alternateQuickStretchedPW = stretcher.getQuickStretchedPW(alternateEmailUTF8);
+          login(alternateEmailUTF8, alternateQuickStretchedPW, getKeys, queryParameters, delegate);
+        } catch (Exception innerException) {
+          delegate.handleError(innerException);
+          return;
+        }
+      }
+    });
+  }
+
+  /**
+   * Registers a device given a valid session token.
+   *
+   * @param sessionToken to query.
+   * @param delegate to invoke callbacks.
+   */
+  @Override
+  public void registerOrUpdateDevice(byte[] sessionToken, FxAccountDevice device, RequestDelegate<FxAccountDevice> delegate) {
+    final byte[] tokenId = new byte[32];
+    final byte[] reqHMACKey = new byte[32];
+    final byte[] requestKey = new byte[32];
+    try {
+      HKDF.deriveMany(sessionToken, new byte[0], FxAccountUtils.KW("sessionToken"), tokenId, reqHMACKey, requestKey);
+    } catch (Exception e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    final BaseResource resource;
+    final ExtendedJSONObject body;
+    try {
+      resource = getBaseResource("account/device");
+      body = device.toJson();
+    } catch (URISyntaxException | UnsupportedEncodingException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<FxAccountDevice>(resource, delegate, ResponseType.JSON_OBJECT, tokenId, reqHMACKey) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+        try {
+          delegate.handleSuccess(FxAccountDevice.fromJson(body));
+        } catch (Exception e) {
+          delegate.handleError(e);
+        }
+      }
+    };
+
+    post(resource, body);
+  }
+
+  @Override
+  public void deviceList(byte[] sessionToken, RequestDelegate<FxAccountDevice[]> delegate) {
+    final byte[] tokenId = new byte[32];
+    final byte[] reqHMACKey = new byte[32];
+    final byte[] requestKey = new byte[32];
+    try {
+      HKDF.deriveMany(sessionToken, new byte[0], FxAccountUtils.KW("sessionToken"), tokenId, reqHMACKey, requestKey);
+    } catch (Exception e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    final BaseResource resource;
+    try {
+      resource = getBaseResource("account/devices");
+    } catch (URISyntaxException | UnsupportedEncodingException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<FxAccountDevice[]>(resource, delegate, ResponseType.JSON_ARRAY, tokenId, reqHMACKey) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, JSONArray devicesJson) {
+        try {
+          FxAccountDevice[] devices = new FxAccountDevice[devicesJson.size()];
+          for (int i = 0; i < devices.length; i++) {
+            ExtendedJSONObject deviceJson = new ExtendedJSONObject((JSONObject) devicesJson.get(i));
+            devices[i] = FxAccountDevice.fromJson(deviceJson);
+          }
+          delegate.handleSuccess(devices);
+        } catch (Exception e) {
+          delegate.handleError(e);
+        }
+      }
+    };
+
+    resource.get();
+  }
+
+  @Override
+  public void notifyDevices(@NonNull byte[] sessionToken, @NonNull List<String> deviceIds, ExtendedJSONObject payload, Long TTL, RequestDelegate<ExtendedJSONObject> delegate) {
+    final byte[] tokenId = new byte[32];
+    final byte[] reqHMACKey = new byte[32];
+    final byte[] requestKey = new byte[32];
+    try {
+      HKDF.deriveMany(sessionToken, new byte[0], FxAccountUtils.KW("sessionToken"), tokenId, reqHMACKey, requestKey);
+    } catch (Exception e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    final BaseResource resource;
+    final ExtendedJSONObject body = createNotifyDevicesBody(deviceIds, payload, TTL);
+    try {
+      resource = getBaseResource("account/devices/notify");
+    } catch (URISyntaxException | UnsupportedEncodingException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<ExtendedJSONObject>(resource, delegate, ResponseType.JSON_OBJECT, tokenId, reqHMACKey) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+        try {
+          delegate.handleSuccess(body);
+        } catch (Exception e) {
+          delegate.handleError(e);
+        }
+      }
+    };
+
+    post(resource, body);
+  }
+
+  @NonNull
+  @SuppressWarnings("unchecked")
+  private ExtendedJSONObject createNotifyDevicesBody(@NonNull List<String> deviceIds, ExtendedJSONObject payload, Long TTL) {
+    final ExtendedJSONObject body = new ExtendedJSONObject();
+    final JSONArray to = new JSONArray();
+    to.addAll(deviceIds);
+    body.put("to", to);
+    if (payload != null) {
+      body.put("payload", payload);
+    }
+    if (TTL != null) {
+      body.put("TTL", TTL);
+    }
+    return body;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountClientException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountClientException.java
new file mode 100644
index 000000000..28ee5630e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountClientException.java
@@ -0,0 +1,133 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import org.mozilla.gecko.R;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.HTTPFailureException;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.HttpStatus;
+
+/**
+ * From <a href="https://github.com/mozilla/fxa-auth-server/blob/master/docs/api.md">https://github.com/mozilla/fxa-auth-server/blob/master/docs/api.md</a>.
+ */
+public class FxAccountClientException extends Exception {
+  private static final long serialVersionUID = 7953459541558266597L;
+
+  public FxAccountClientException(String detailMessage) {
+    super(detailMessage);
+  }
+
+  public FxAccountClientException(Exception e) {
+    super(e);
+  }
+
+  public static class FxAccountClientRemoteException extends FxAccountClientException {
+    private static final long serialVersionUID = 2209313149952001097L;
+
+    public final HttpResponse response;
+    public final long httpStatusCode;
+    public final long apiErrorNumber;
+    public final String error;
+    public final String message;
+    public final String info;
+    public final ExtendedJSONObject body;
+
+    public FxAccountClientRemoteException(HttpResponse response, long httpStatusCode, long apiErrorNumber, String error, String message, String info, ExtendedJSONObject body) {
+      super(new HTTPFailureException(new SyncStorageResponse(response)));
+      if (body == null) {
+        throw new IllegalArgumentException("body must not be null");
+      }
+      this.response = response;
+      this.httpStatusCode = httpStatusCode;
+      this.apiErrorNumber = apiErrorNumber;
+      this.error = error;
+      this.message = message;
+      this.info = info;
+      this.body = body;
+    }
+
+    @Override
+    public String toString() {
+      return "<FxAccountClientRemoteException " + this.httpStatusCode + " [" + this.apiErrorNumber + "]: " + this.message + ">";
+    }
+
+    public boolean isInvalidAuthentication() {
+      return httpStatusCode == HttpStatus.SC_UNAUTHORIZED;
+    }
+
+    public boolean isAccountAlreadyExists() {
+      return apiErrorNumber == FxAccountRemoteError.ATTEMPT_TO_CREATE_AN_ACCOUNT_THAT_ALREADY_EXISTS;
+    }
+
+    public boolean isAccountDoesNotExist() {
+      return apiErrorNumber == FxAccountRemoteError.ATTEMPT_TO_ACCESS_AN_ACCOUNT_THAT_DOES_NOT_EXIST;
+    }
+
+    public boolean isBadPassword() {
+      return apiErrorNumber == FxAccountRemoteError.INCORRECT_PASSWORD;
+    }
+
+    public boolean isUnverified() {
+      return apiErrorNumber == FxAccountRemoteError.ATTEMPT_TO_OPERATE_ON_AN_UNVERIFIED_ACCOUNT;
+    }
+
+    public boolean isUpgradeRequired() {
+      return
+          apiErrorNumber == FxAccountRemoteError.ENDPOINT_IS_NO_LONGER_SUPPORTED ||
+          apiErrorNumber == FxAccountRemoteError.INCORRECT_LOGIN_METHOD_FOR_THIS_ACCOUNT ||
+          apiErrorNumber == FxAccountRemoteError.INCORRECT_KEY_RETRIEVAL_METHOD_FOR_THIS_ACCOUNT ||
+          apiErrorNumber == FxAccountRemoteError.INCORRECT_API_VERSION_FOR_THIS_ACCOUNT;
+    }
+
+    public boolean isTooManyRequests() {
+      return apiErrorNumber == FxAccountRemoteError.CLIENT_HAS_SENT_TOO_MANY_REQUESTS;
+    }
+
+    public boolean isServerUnavailable() {
+      return apiErrorNumber == FxAccountRemoteError.SERVICE_TEMPORARILY_UNAVAILABLE_DUE_TO_HIGH_LOAD;
+    }
+
+    public boolean isBadEmailCase() {
+      return apiErrorNumber == FxAccountRemoteError.INCORRECT_EMAIL_CASE;
+    }
+
+    public boolean isAccountLocked() {
+      return apiErrorNumber == FxAccountRemoteError.ACCOUNT_LOCKED;
+    }
+
+    public int getErrorMessageStringResource() {
+      if (isUpgradeRequired()) {
+        return R.string.fxaccount_remote_error_UPGRADE_REQUIRED;
+      } else if (isAccountAlreadyExists()) {
+        return R.string.fxaccount_remote_error_ATTEMPT_TO_CREATE_AN_ACCOUNT_THAT_ALREADY_EXISTS;
+      } else if (isAccountDoesNotExist()) {
+        return R.string.fxaccount_remote_error_ATTEMPT_TO_ACCESS_AN_ACCOUNT_THAT_DOES_NOT_EXIST;
+      } else if (isBadPassword()) {
+        return R.string.fxaccount_remote_error_INCORRECT_PASSWORD;
+      } else if (isUnverified()) {
+        return R.string.fxaccount_remote_error_ATTEMPT_TO_OPERATE_ON_AN_UNVERIFIED_ACCOUNT;
+      } else if (isTooManyRequests()) {
+        return R.string.fxaccount_remote_error_CLIENT_HAS_SENT_TOO_MANY_REQUESTS;
+      } else if (isServerUnavailable()) {
+        return R.string.fxaccount_remote_error_SERVICE_TEMPORARILY_UNAVAILABLE_TO_DUE_HIGH_LOAD;
+      } else if (isAccountLocked()) {
+        return R.string.fxaccount_remote_error_ACCOUNT_LOCKED;
+      } else {
+        return R.string.fxaccount_remote_error_UNKNOWN_ERROR;
+      }
+    }
+  }
+
+  public static class FxAccountClientMalformedResponseException extends FxAccountClientRemoteException {
+    private static final long serialVersionUID = 2209313149952001098L;
+
+    public FxAccountClientMalformedResponseException(HttpResponse response) {
+      super(response, 0, FxAccountRemoteError.UNKNOWN_ERROR, "Response malformed", "Response malformed", "Response malformed", new ExtendedJSONObject());
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountRemoteError.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountRemoteError.java
new file mode 100644
index 000000000..5a89561cb
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountRemoteError.java
@@ -0,0 +1,33 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+public interface FxAccountRemoteError {
+  public static final int ATTEMPT_TO_CREATE_AN_ACCOUNT_THAT_ALREADY_EXISTS = 101;
+  public static final int ATTEMPT_TO_ACCESS_AN_ACCOUNT_THAT_DOES_NOT_EXIST = 102;
+  public static final int INCORRECT_PASSWORD = 103;
+  public static final int ATTEMPT_TO_OPERATE_ON_AN_UNVERIFIED_ACCOUNT = 104;
+  public static final int INVALID_VERIFICATION_CODE = 105;
+  public static final int REQUEST_BODY_WAS_NOT_VALID_JSON = 106;
+  public static final int REQUEST_BODY_CONTAINS_INVALID_PARAMETERS = 107;
+  public static final int REQUEST_BODY_MISSING_REQUIRED_PARAMETERS = 108;
+  public static final int INVALID_REQUEST_SIGNATURE = 109;
+  public static final int INVALID_AUTHENTICATION_TOKEN = 110;
+  public static final int INVALID_AUTHENTICATION_TIMESTAMP = 111;
+  public static final int CONTENT_LENGTH_HEADER_WAS_NOT_PROVIDED = 112;
+  public static final int REQUEST_BODY_TOO_LARGE = 113;
+  public static final int CLIENT_HAS_SENT_TOO_MANY_REQUESTS = 114;
+  public static final int INVALID_NONCE_IN_REQUEST_SIGNATURE = 115;
+  public static final int ENDPOINT_IS_NO_LONGER_SUPPORTED = 116;
+  public static final int INCORRECT_LOGIN_METHOD_FOR_THIS_ACCOUNT = 117;
+  public static final int INCORRECT_KEY_RETRIEVAL_METHOD_FOR_THIS_ACCOUNT = 118;
+  public static final int INCORRECT_API_VERSION_FOR_THIS_ACCOUNT = 119;
+  public static final int INCORRECT_EMAIL_CASE = 120;
+  public static final int ACCOUNT_LOCKED = 121;
+  public static final int UNKNOWN_DEVICE = 123;
+  public static final int DEVICE_SESSION_CONFLICT = 124;
+  public static final int SERVICE_TEMPORARILY_UNAVAILABLE_DUE_TO_HIGH_LOAD = 201;
+  public static final int UNKNOWN_ERROR = 999;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountUtils.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountUtils.java
new file mode 100644
index 000000000..2d29725a0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/FxAccountUtils.java
@@ -0,0 +1,217 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import java.io.UnsupportedEncodingException;
+import java.math.BigInteger;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+
+import org.mozilla.gecko.AppConstants;
+import org.mozilla.gecko.R;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.nativecode.NativeCrypto;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.crypto.HKDF;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.crypto.PBKDF2;
+
+import android.content.Context;
+
+public class FxAccountUtils {
+  private static final String LOG_TAG = FxAccountUtils.class.getSimpleName();
+
+  public static final int SALT_LENGTH_BYTES = 32;
+  public static final int SALT_LENGTH_HEX = 2 * SALT_LENGTH_BYTES;
+
+  public static final int HASH_LENGTH_BYTES = 16;
+  public static final int HASH_LENGTH_HEX = 2 * HASH_LENGTH_BYTES;
+
+  public static final int CRYPTO_KEY_LENGTH_BYTES = 32;
+  public static final int CRYPTO_KEY_LENGTH_HEX = 2 * CRYPTO_KEY_LENGTH_BYTES;
+
+  public static final String KW_VERSION_STRING = "identity.mozilla.com/picl/v1/";
+
+  public static final int NUMBER_OF_QUICK_STRETCH_ROUNDS = 1000;
+
+  // For extra debugging.  Not final so it can be changed from Fennec, or from
+  // an add-on.
+  public static boolean LOG_PERSONAL_INFORMATION = false;
+
+  public static void pii(String tag, String message) {
+    if (FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+      Logger.info(tag, "$$FxA PII$$: " + message);
+    }
+  }
+
+  public static String bytes(String string) throws UnsupportedEncodingException {
+    return Utils.byte2Hex(string.getBytes("UTF-8"));
+  }
+
+  public static byte[] KW(String name) throws UnsupportedEncodingException {
+    return Utils.concatAll(
+        KW_VERSION_STRING.getBytes("UTF-8"),
+        name.getBytes("UTF-8"));
+  }
+
+  public static byte[] KWE(String name, byte[] emailUTF8) throws UnsupportedEncodingException {
+    return Utils.concatAll(
+        KW_VERSION_STRING.getBytes("UTF-8"),
+        name.getBytes("UTF-8"),
+        ":".getBytes("UTF-8"),
+        emailUTF8);
+  }
+
+  /**
+   * Calculate the SRP verifier <tt>x</tt> value.
+   */
+  public static BigInteger srpVerifierLowercaseX(byte[] emailUTF8, byte[] srpPWBytes, byte[] srpSaltBytes)
+      throws NoSuchAlgorithmException, UnsupportedEncodingException {
+    byte[] inner = Utils.sha256(Utils.concatAll(emailUTF8, ":".getBytes("UTF-8"), srpPWBytes));
+    byte[] outer = Utils.sha256(Utils.concatAll(srpSaltBytes, inner));
+    return new BigInteger(1, outer);
+  }
+
+  /**
+   * Calculate the SRP verifier <tt>v</tt> value.
+   */
+  public static BigInteger srpVerifierLowercaseV(byte[] emailUTF8, byte[] srpPWBytes, byte[] srpSaltBytes, BigInteger g, BigInteger N)
+      throws NoSuchAlgorithmException, UnsupportedEncodingException {
+    BigInteger x = srpVerifierLowercaseX(emailUTF8, srpPWBytes, srpSaltBytes);
+    BigInteger v = g.modPow(x, N);
+    return v;
+  }
+
+  /**
+   * Format x modulo N in hexadecimal, using as many characters as N takes (in hexadecimal).
+   * @param x to format.
+   * @param N modulus.
+   * @return x modulo N in hexadecimal.
+   */
+  public static String hexModN(BigInteger x, BigInteger N) {
+    int byteLength = (N.bitLength() + 7) / 8;
+    int hexLength = 2 * byteLength;
+    return Utils.byte2Hex(Utils.hex2Byte((x.mod(N)).toString(16), byteLength), hexLength);
+  }
+
+  /**
+   * The first engineering milestone of PICL (Profile-in-the-Cloud) was
+   * comprised of Sync 1.1 fronted by a Firefox Account. The sync key was
+   * generated from the Firefox Account password-derived kB value using this
+   * method.
+   */
+  public static KeyBundle generateSyncKeyBundle(final byte[] kB) throws InvalidKeyException, NoSuchAlgorithmException, UnsupportedEncodingException {
+    byte[] encryptionKey = new byte[32];
+    byte[] hmacKey = new byte[32];
+    byte[] derived = HKDF.derive(kB, new byte[0], FxAccountUtils.KW("oldsync"), 2*32);
+    System.arraycopy(derived, 0*32, encryptionKey, 0, 1*32);
+    System.arraycopy(derived, 1*32, hmacKey, 0, 1*32);
+    return new KeyBundle(encryptionKey, hmacKey);
+  }
+
+  /**
+   * Firefox Accounts are password authenticated, but clients should not store
+   * the plain-text password for any amount of time. Equivalent, but slightly
+   * more secure, is the quickly client-side stretched password.
+   * <p>
+   * We separate this since multiple login-time operations want it, and the
+   * PBKDF2 operation is computationally expensive.
+   */
+  public static byte[] generateQuickStretchedPW(byte[] emailUTF8, byte[] passwordUTF8) throws GeneralSecurityException, UnsupportedEncodingException {
+    byte[] S = FxAccountUtils.KWE("quickStretch", emailUTF8);
+    try {
+      return NativeCrypto.pbkdf2SHA256(passwordUTF8, S, NUMBER_OF_QUICK_STRETCH_ROUNDS, 32);
+    } catch (final LinkageError e) {
+      // This will throw UnsatisfiedLinkError (missing mozglue) the first time it is called, and
+      // ClassNotDefFoundError, for the uninitialized NativeCrypto class, each subsequent time this
+      // is called; LinkageError is their common ancestor.
+      Logger.warn(LOG_TAG, "Got throwable stretching password using native pbkdf2SHA256 " +
+          "implementation; ignoring and using Java implementation.", e);
+      return PBKDF2.pbkdf2SHA256(passwordUTF8, S, NUMBER_OF_QUICK_STRETCH_ROUNDS, 32);
+    }
+  }
+
+  /**
+   * The password-derived credential used to authenticate to the Firefox Account
+   * auth server.
+   */
+  public static byte[] generateAuthPW(byte[] quickStretchedPW) throws GeneralSecurityException, UnsupportedEncodingException {
+    return HKDF.derive(quickStretchedPW, new byte[0], FxAccountUtils.KW("authPW"), 32);
+  }
+
+  /**
+   * The password-derived credential used to unwrap keys managed by the Firefox
+   * Account auth server.
+   */
+  public static byte[] generateUnwrapBKey(byte[] quickStretchedPW) throws GeneralSecurityException, UnsupportedEncodingException {
+    return HKDF.derive(quickStretchedPW, new byte[0], FxAccountUtils.KW("unwrapBkey"), 32);
+  }
+
+  public static byte[] unwrapkB(byte[] unwrapkB, byte[] wrapkB) {
+    if (unwrapkB == null) {
+      throw new IllegalArgumentException("unwrapkB must not be null");
+    }
+    if (wrapkB == null) {
+      throw new IllegalArgumentException("wrapkB must not be null");
+    }
+    if (unwrapkB.length != CRYPTO_KEY_LENGTH_BYTES || wrapkB.length != CRYPTO_KEY_LENGTH_BYTES) {
+      throw new IllegalArgumentException("unwrapkB and wrapkB must be " + CRYPTO_KEY_LENGTH_BYTES + " bytes long");
+    }
+    byte[] kB = new byte[CRYPTO_KEY_LENGTH_BYTES];
+    for (int i = 0; i < wrapkB.length; i++) {
+      kB[i] = (byte) (wrapkB[i] ^ unwrapkB[i]);
+    }
+    return kB;
+  }
+
+  /**
+   * The token server accepts an X-Client-State header, which is the
+   * lowercase-hex-encoded first 16 bytes of the SHA-256 hash of the
+   * bytes of kB.
+   * @param kB a byte array, expected to be 32 bytes long.
+   * @return a 32-character string.
+   * @throws NoSuchAlgorithmException
+   */
+  public static String computeClientState(byte[] kB) throws NoSuchAlgorithmException {
+    if (kB == null ||
+        kB.length != 32) {
+      throw new IllegalArgumentException("Unexpected kB.");
+    }
+    byte[] sha256 = Utils.sha256(kB);
+    byte[] truncated = new byte[16];
+    System.arraycopy(sha256, 0, truncated, 0, 16);
+    return Utils.byte2Hex(truncated);    // This is automatically lowercase.
+  }
+
+  /**
+   * Given an endpoint, calculate the corresponding BrowserID audience.
+   * <p>
+   * This is the domain, in web parlance.
+   *
+   * @param serverURI endpoint.
+   * @return BrowserID audience.
+   * @throws URISyntaxException
+   */
+  public static String getAudienceForURL(String serverURI) throws URISyntaxException {
+    URI uri = new URI(serverURI);
+    return new URI(uri.getScheme(), null, uri.getHost(), uri.getPort(), null, null, null).toString();
+  }
+
+  public static String defaultClientName(Context context) {
+    String name = AppConstants.MOZ_APP_DISPLAYNAME; // The display name is never translated.
+    // Change "Firefox Aurora" or similar into "Aurora".
+    if (name.contains("Aurora")) {
+        name = "Aurora";
+    } else if (name.contains("Beta")) {
+        name = "Beta";
+    } else if (name.contains("Nightly")) {
+        name = "Nightly";
+    }
+    return context.getResources().getString(R.string.sync_default_client_name, name, android.os.Build.MODEL);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/PasswordStretcher.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/PasswordStretcher.java
new file mode 100644
index 000000000..2debf3c77
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/PasswordStretcher.java
@@ -0,0 +1,12 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import java.io.UnsupportedEncodingException;
+import java.security.GeneralSecurityException;
+
+public interface PasswordStretcher {
+  public byte[] getQuickStretchedPW(byte[] emailUTF8) throws UnsupportedEncodingException, GeneralSecurityException;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/QuickPasswordStretcher.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/QuickPasswordStretcher.java
new file mode 100644
index 000000000..bf4b1bc97
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/QuickPasswordStretcher.java
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import java.io.UnsupportedEncodingException;
+import java.security.GeneralSecurityException;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.mozilla.gecko.sync.Utils;
+
+public class QuickPasswordStretcher implements PasswordStretcher {
+  protected final String password;
+  protected final Map<String, String> cache = new HashMap<String, String>();
+
+  public QuickPasswordStretcher(String password) {
+    this.password = password;
+  }
+
+  @Override
+  public synchronized byte[] getQuickStretchedPW(byte[] emailUTF8) throws UnsupportedEncodingException, GeneralSecurityException {
+    if (emailUTF8 == null) {
+      throw new IllegalArgumentException("emailUTF8 must not be null");
+    }
+    String key = Utils.byte2Hex(emailUTF8);
+    if (!cache.containsKey(key)) {
+      byte[] value = FxAccountUtils.generateQuickStretchedPW(emailUTF8, password.getBytes("UTF-8"));
+      cache.put(key, Utils.byte2Hex(value));
+      return value;
+    }
+    return Utils.hex2Byte(cache.get(key));
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/SkewHandler.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/SkewHandler.java
new file mode 100644
index 000000000..9d0ad5e03
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/SkewHandler.java
@@ -0,0 +1,111 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.HashMap;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.net.Resource;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.HttpHeaders;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.impl.cookie.DateParseException;
+import ch.boye.httpclientandroidlib.impl.cookie.DateUtils;
+
+public class SkewHandler {
+  private static final String LOG_TAG = "SkewHandler";
+  protected volatile long skewMillis = 0L;
+  protected final String hostname;
+
+  private static final HashMap<String, SkewHandler> skewHandlers = new HashMap<String, SkewHandler>();
+
+  public static SkewHandler getSkewHandlerForResource(final Resource resource) {
+    return getSkewHandlerForHostname(resource.getHostname());
+  }
+
+  public static SkewHandler getSkewHandlerFromEndpointString(final String url) throws URISyntaxException {
+    if (url == null) {
+      throw new IllegalArgumentException("url must not be null.");
+    }
+    URI u = new URI(url);
+    return getSkewHandlerForHostname(u.getHost());
+  }
+
+  public static synchronized SkewHandler getSkewHandlerForHostname(final String hostname) {
+    SkewHandler handler = skewHandlers.get(hostname);
+    if (handler == null) {
+      handler = new SkewHandler(hostname);
+      skewHandlers.put(hostname, handler);
+    }
+    return handler;
+  }
+
+  public static synchronized void clearSkewHandlers() {
+    skewHandlers.clear();
+  }
+
+  public SkewHandler(final String hostname) {
+    this.hostname = hostname;
+  }
+
+  public boolean updateSkewFromServerMillis(long millis, long now) {
+    skewMillis = millis - now;
+    Logger.debug(LOG_TAG, "Updated skew: " + skewMillis + "ms for hostname " + this.hostname);
+    return true;
+  }
+
+  public boolean updateSkewFromHTTPDateString(String date, long now) {
+    try {
+      final long millis = DateUtils.parseDate(date).getTime();
+      return updateSkewFromServerMillis(millis, now);
+    } catch (DateParseException e) {
+      Logger.warn(LOG_TAG, "Unexpected: invalid Date header from " + this.hostname);
+      return false;
+    }
+  }
+
+  public boolean updateSkewFromDateHeader(Header header, long now) {
+    String date = header.getValue();
+    if (null == date) {
+      Logger.warn(LOG_TAG, "Unexpected: null Date header from " + this.hostname);
+      return false;
+    }
+    return updateSkewFromHTTPDateString(date, now);
+  }
+
+  /**
+   * Update our tracked skew value to account for the local clock differing from
+   * the server's.
+   * 
+   * @param response
+   *          the received HTTP response.
+   * @param now
+   *          the current time in milliseconds.
+   * @return true if the skew value was updated, false otherwise.
+   */
+  public boolean updateSkew(HttpResponse response, long now) {
+    Header header = response.getFirstHeader(HttpHeaders.DATE);
+    if (null == header) {
+      Logger.warn(LOG_TAG, "Unexpected: missing Date header from " + this.hostname);
+      return false;
+    }
+    return updateSkewFromDateHeader(header, now);
+  }
+
+  public long getSkewInMillis() {
+    return skewMillis;
+  }
+
+  public long getSkewInSeconds() {
+    return skewMillis / 1000;
+  }
+
+  public void resetSkew() {
+    skewMillis = 0L;
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountAbstractClient.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountAbstractClient.java
new file mode 100644
index 000000000..4bdaa6690
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountAbstractClient.java
@@ -0,0 +1,224 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa.oauth;
+
+import java.io.IOException;
+import java.security.GeneralSecurityException;
+import java.util.Locale;
+import java.util.concurrent.Executor;
+
+import org.mozilla.gecko.background.fxa.FxAccountClientException;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountAbstractClientException.FxAccountAbstractClientMalformedResponseException;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountAbstractClientException.FxAccountAbstractClientRemoteException;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.Locales;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.BaseResource;
+import org.mozilla.gecko.sync.net.BaseResourceDelegate;
+import org.mozilla.gecko.sync.net.Resource;
+import org.mozilla.gecko.sync.net.SyncResponse;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+import ch.boye.httpclientandroidlib.HttpEntity;
+import ch.boye.httpclientandroidlib.HttpHeaders;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.ClientProtocolException;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+
+public abstract class FxAccountAbstractClient {
+  protected static final String LOG_TAG = FxAccountAbstractClient.class.getSimpleName();
+
+  protected static final String ACCEPT_HEADER = "application/json;charset=utf-8";
+  protected static final String AUTHORIZATION_RESPONSE_TYPE = "token";
+
+  public static final String JSON_KEY_ERROR = "error";
+  public static final String JSON_KEY_MESSAGE = "message";
+  public static final String JSON_KEY_CODE = "code";
+  public static final String JSON_KEY_ERRNO = "errno";
+
+  protected static final String[] requiredErrorStringFields = { JSON_KEY_ERROR, JSON_KEY_MESSAGE };
+  protected static final String[] requiredErrorLongFields = { JSON_KEY_CODE, JSON_KEY_ERRNO };
+
+  /**
+   * The server's URI.
+   * <p>
+   * We assume throughout that this ends with a trailing slash (and guarantee as
+   * much in the constructor).
+   */
+  protected final String serverURI;
+
+  protected final Executor executor;
+
+  public FxAccountAbstractClient(String serverURI, Executor executor) {
+    if (serverURI == null) {
+      throw new IllegalArgumentException("Must provide a server URI.");
+    }
+    if (executor == null) {
+      throw new IllegalArgumentException("Must provide a non-null executor.");
+    }
+    this.serverURI = serverURI.endsWith("/") ? serverURI : serverURI + "/";
+    if (!this.serverURI.endsWith("/")) {
+      throw new IllegalArgumentException("Constructed serverURI must end with a trailing slash: " + this.serverURI);
+    }
+    this.executor = executor;
+  }
+
+  /**
+   * Process a typed value extracted from a successful response (in an
+   * endpoint-dependent way).
+   */
+  public interface RequestDelegate<T> {
+    public void handleError(Exception e);
+    public void handleFailure(FxAccountAbstractClientRemoteException e);
+    public void handleSuccess(T result);
+  }
+
+  /**
+   * Intepret a response from the auth server.
+   * <p>
+   * Throw an appropriate exception on errors; otherwise, return the response's
+   * status code.
+   *
+   * @return response's HTTP status code.
+   * @throws FxAccountClientException
+   */
+  public static int validateResponse(HttpResponse response) throws FxAccountAbstractClientRemoteException {
+    final int status = response.getStatusLine().getStatusCode();
+    if (status == 200) {
+      return status;
+    }
+    int code;
+    int errno;
+    String error;
+    String message;
+    ExtendedJSONObject body;
+    try {
+      body = new SyncStorageResponse(response).jsonObjectBody();
+      body.throwIfFieldsMissingOrMisTyped(requiredErrorStringFields, String.class);
+      body.throwIfFieldsMissingOrMisTyped(requiredErrorLongFields, Long.class);
+      code = body.getLong(JSON_KEY_CODE).intValue();
+      errno = body.getLong(JSON_KEY_ERRNO).intValue();
+      error = body.getString(JSON_KEY_ERROR);
+      message = body.getString(JSON_KEY_MESSAGE);
+    } catch (Exception e) {
+      throw new FxAccountAbstractClientMalformedResponseException(response);
+    }
+    throw new FxAccountAbstractClientRemoteException(response, code, errno, error, message, body);
+  }
+
+  protected <T> void invokeHandleError(final RequestDelegate<T> delegate, final Exception e) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        delegate.handleError(e);
+      }
+    });
+  }
+
+  protected <T> void post(BaseResource resource, final ExtendedJSONObject requestBody, final RequestDelegate<T> delegate) {
+    try {
+      if (requestBody == null) {
+        resource.post((HttpEntity) null);
+      } else {
+        resource.post(requestBody);
+      }
+    } catch (Exception e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+  }
+
+  /**
+   * Translate resource callbacks into request callbacks invoked on the provided
+   * executor.
+   * <p>
+   * Override <code>handleSuccess</code> to parse the body of the resource
+   * request and call the request callback. <code>handleSuccess</code> is
+   * invoked via the executor, so you don't need to delegate further.
+   */
+  protected abstract class ResourceDelegate<T> extends BaseResourceDelegate {
+    protected abstract void handleSuccess(final int status, HttpResponse response, final ExtendedJSONObject body);
+
+    protected final RequestDelegate<T> delegate;
+
+    /**
+     * Create a delegate for an un-authenticated resource.
+     */
+    public ResourceDelegate(final Resource resource, final RequestDelegate<T> delegate) {
+      super(resource);
+      this.delegate = delegate;
+    }
+
+    @Override
+    public AuthHeaderProvider getAuthHeaderProvider() {
+      return super.getAuthHeaderProvider();
+    }
+
+    @Override
+    public String getUserAgent() {
+      return FxAccountConstants.USER_AGENT;
+    }
+
+    @Override
+    public void handleHttpResponse(HttpResponse response) {
+      try {
+        final int status = validateResponse(response);
+        invokeHandleSuccess(status, response);
+      } catch (FxAccountAbstractClientRemoteException e) {
+        invokeHandleFailure(e);
+      }
+    }
+
+    protected void invokeHandleFailure(final FxAccountAbstractClientRemoteException e) {
+      executor.execute(new Runnable() {
+        @Override
+        public void run() {
+          delegate.handleFailure(e);
+        }
+      });
+    }
+
+    protected void invokeHandleSuccess(final int status, final HttpResponse response) {
+      executor.execute(new Runnable() {
+        @Override
+        public void run() {
+          try {
+            ExtendedJSONObject body = new SyncResponse(response).jsonObjectBody();
+            ResourceDelegate.this.handleSuccess(status, response, body);
+          } catch (Exception e) {
+            delegate.handleError(e);
+          }
+        }
+      });
+    }
+
+    @Override
+    public void handleHttpProtocolException(final ClientProtocolException e) {
+      invokeHandleError(delegate, e);
+    }
+
+    @Override
+    public void handleHttpIOException(IOException e) {
+      invokeHandleError(delegate, e);
+    }
+
+    @Override
+    public void handleTransportException(GeneralSecurityException e) {
+      invokeHandleError(delegate, e);
+    }
+
+    @Override
+    public void addHeaders(HttpRequestBase request, DefaultHttpClient client) {
+      super.addHeaders(request, client);
+
+      // The basics.
+      final Locale locale = Locale.getDefault();
+      request.addHeader(HttpHeaders.ACCEPT_LANGUAGE, Locales.getLanguageTag(locale));
+      request.addHeader(HttpHeaders.ACCEPT, ACCEPT_HEADER);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountAbstractClientException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountAbstractClientException.java
new file mode 100644
index 000000000..21025af0a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountAbstractClientException.java
@@ -0,0 +1,68 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa.oauth;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.HTTPFailureException;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.HttpStatus;
+
+/**
+ * From <a href="https://github.com/mozilla/fxa-auth-server/blob/master/docs/api.md">https://github.com/mozilla/fxa-auth-server/blob/master/docs/api.md</a>.
+ */
+public class FxAccountAbstractClientException extends Exception {
+  private static final long serialVersionUID = 1953459541558266597L;
+
+  public FxAccountAbstractClientException(String detailMessage) {
+    super(detailMessage);
+  }
+
+  public FxAccountAbstractClientException(Exception e) {
+    super(e);
+  }
+
+  public static class FxAccountAbstractClientRemoteException extends FxAccountAbstractClientException {
+    private static final long serialVersionUID = 1209313149952001097L;
+
+    public final HttpResponse response;
+    public final long httpStatusCode;
+    public final long apiErrorNumber;
+    public final String error;
+    public final String message;
+    public final ExtendedJSONObject body;
+
+    public FxAccountAbstractClientRemoteException(HttpResponse response, long httpStatusCode, long apiErrorNumber, String error, String message, ExtendedJSONObject body) {
+      super(new HTTPFailureException(new SyncStorageResponse(response)));
+      if (body == null) {
+        throw new IllegalArgumentException("body must not be null");
+      }
+      this.response = response;
+      this.httpStatusCode = httpStatusCode;
+      this.apiErrorNumber = apiErrorNumber;
+      this.error = error;
+      this.message = message;
+      this.body = body;
+    }
+
+    @Override
+    public String toString() {
+      return "<FxAccountAbstractClientRemoteException " + this.httpStatusCode + " [" + this.apiErrorNumber + "]: " + this.message + ">";
+    }
+
+    public boolean isInvalidAuthentication() {
+      return this.httpStatusCode == HttpStatus.SC_UNAUTHORIZED;
+    }
+  }
+
+  public static class FxAccountAbstractClientMalformedResponseException extends FxAccountAbstractClientRemoteException {
+    private static final long serialVersionUID = 1209313149952001098L;
+
+    public FxAccountAbstractClientMalformedResponseException(HttpResponse response) {
+      super(response, 0, FxAccountOAuthRemoteError.UNKNOWN_ERROR, "Response malformed", "Response malformed", new ExtendedJSONObject());
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountOAuthClient10.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountOAuthClient10.java
new file mode 100644
index 000000000..4f233695b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountOAuthClient10.java
@@ -0,0 +1,129 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa.oauth;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.concurrent.Executor;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.net.BaseResource;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+
+/**
+ * Talk to an fxa-oauth-server to get "implicitly granted" OAuth tokens.
+ * <p>
+ * To use this client, you will need a pre-allocated fxa-oauth-server
+ * "client_id" with special "implicit grant" permissions.
+ * <p>
+ * This client was written against the API documented at <a href="https://github.com/mozilla/fxa-oauth-server/blob/41538990df9e91158558ae5a8115194383ac3b05/docs/api.md">https://github.com/mozilla/fxa-oauth-server/blob/41538990df9e91158558ae5a8115194383ac3b05/docs/api.md</a>.
+ */
+public class FxAccountOAuthClient10 extends FxAccountAbstractClient {
+  protected static final String LOG_TAG = FxAccountOAuthClient10.class.getSimpleName();
+
+  protected static final String AUTHORIZATION_RESPONSE_TYPE = "token";
+
+  protected static final String JSON_KEY_ACCESS_TOKEN = "access_token";
+  protected static final String JSON_KEY_ASSERTION = "assertion";
+  protected static final String JSON_KEY_CLIENT_ID = "client_id";
+  protected static final String JSON_KEY_RESPONSE_TYPE = "response_type";
+  protected static final String JSON_KEY_SCOPE = "scope";
+  protected static final String JSON_KEY_STATE = "state";
+  protected static final String JSON_KEY_TOKEN = "token";
+  protected static final String JSON_KEY_TOKEN_TYPE = "token_type";
+
+  // access_token: A string that can be used for authorized requests to service providers.
+  // scope: A string of space-separated permissions that this token has. May differ from requested scopes, since user can deny permissions.
+  // token_type: A string representing the token type. Currently will always be "bearer".
+  protected static final String[] AUTHORIZATION_RESPONSE_REQUIRED_STRING_FIELDS = new String[] { JSON_KEY_ACCESS_TOKEN, JSON_KEY_SCOPE, JSON_KEY_TOKEN_TYPE };
+
+  public FxAccountOAuthClient10(String serverURI, Executor executor) {
+    super(serverURI, executor);
+  }
+
+  /**
+   * Thin container for an authorization response.
+   */
+  public static class AuthorizationResponse {
+    public final String access_token;
+    public final String token_type;
+    public final String scope;
+
+    public AuthorizationResponse(String access_token, String token_type, String scope) {
+      this.access_token = access_token;
+      this.token_type = token_type;
+      this.scope = scope;
+    }
+  }
+
+  public void authorization(String client_id, String assertion, String state, String scope,
+                            RequestDelegate<AuthorizationResponse> delegate) {
+    final BaseResource resource;
+    try {
+      resource = new BaseResource(new URI(serverURI + "authorization"));
+    } catch (URISyntaxException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<AuthorizationResponse>(resource, delegate) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+        try {
+          body.throwIfFieldsMissingOrMisTyped(AUTHORIZATION_RESPONSE_REQUIRED_STRING_FIELDS, String.class);
+          String access_token = body.getString(JSON_KEY_ACCESS_TOKEN);
+          String token_type = body.getString(JSON_KEY_TOKEN_TYPE);
+          String scope = body.getString(JSON_KEY_SCOPE);
+          delegate.handleSuccess(new AuthorizationResponse(access_token, token_type, scope));
+          return;
+        } catch (Exception e) {
+          delegate.handleError(e);
+          return;
+        }
+      }
+    };
+
+    final ExtendedJSONObject requestBody = new ExtendedJSONObject();
+    requestBody.put(JSON_KEY_RESPONSE_TYPE, AUTHORIZATION_RESPONSE_TYPE);
+    requestBody.put(JSON_KEY_CLIENT_ID, client_id);
+    requestBody.put(JSON_KEY_ASSERTION, assertion);
+    if (scope != null) {
+      requestBody.put(JSON_KEY_SCOPE, scope);
+    }
+    if (state != null) {
+      requestBody.put(JSON_KEY_STATE, state);
+    }
+
+    post(resource, requestBody, delegate);
+  }
+
+  public void deleteToken(final String token, final RequestDelegate<Void> delegate) {
+    final BaseResource resource;
+    try {
+      resource = new BaseResource(new URI(serverURI + "destroy"));
+    } catch (URISyntaxException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<Void>(resource, delegate) {
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+        try {
+          delegate.handleSuccess(null);
+          return;
+        } catch (Exception e) {
+          delegate.handleError(e);
+          return;
+        }
+      }
+    };
+
+    final ExtendedJSONObject requestBody = new ExtendedJSONObject();
+    requestBody.put(JSON_KEY_TOKEN, token);
+    post(resource, requestBody, delegate);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountOAuthRemoteError.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountOAuthRemoteError.java
new file mode 100644
index 000000000..d949d316b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/oauth/FxAccountOAuthRemoteError.java
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa.oauth;
+
+public interface FxAccountOAuthRemoteError {
+  public static final int ATTEMPT_TO_CREATE_AN_ACCOUNT_THAT_ALREADY_EXISTS = 101;
+  public static final int UNKNOWN_CLIENT_ID = 101;
+  public static final int INCORRECT_CLIENT_SECRET = 102;
+  public static final int REDIRECT_URI_DOES_NOT_MATCH_REGISTERED_VALUE = 103;
+  public static final int INVALID_FXA_ASSERTION = 104;
+  public static final int UNKNOWN_CODE = 105;
+  public static final int INCORRECT_CODE = 106;
+  public static final int EXPIRED_CODE = 107;
+  public static final int INVALID_TOKEN = 108;
+  public static final int INVALID_REQUEST_PARAMETER = 109;
+  public static final int UNKNOWN_ERROR = 999;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/profile/FxAccountProfileClient10.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/profile/FxAccountProfileClient10.java
new file mode 100644
index 000000000..cb851a8db
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/fxa/profile/FxAccountProfileClient10.java
@@ -0,0 +1,59 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.fxa.profile;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.concurrent.Executor;
+
+import org.mozilla.gecko.background.fxa.oauth.FxAccountAbstractClient;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.BaseResource;
+import org.mozilla.gecko.sync.net.BearerAuthHeaderProvider;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+
+
+/**
+ * Talk to an fxa-profile-server to get profile information like name, age, gender, and avatar image.
+ * <p>
+ * This client was written against the API documented at <a href="https://github.com/mozilla/fxa-profile-server/blob/0c065619f5a2e867f813a343b4c67da3fe2c82a4/docs/API.md">https://github.com/mozilla/fxa-profile-server/blob/0c065619f5a2e867f813a343b4c67da3fe2c82a4/docs/API.md</a>.
+ */
+public class FxAccountProfileClient10 extends FxAccountAbstractClient {
+  public FxAccountProfileClient10(String serverURI, Executor executor) {
+    super(serverURI, executor);
+  }
+
+  public void profile(final String token, RequestDelegate<ExtendedJSONObject> delegate) {
+    BaseResource resource;
+    try {
+      resource = new BaseResource(new URI(serverURI + "profile"));
+    } catch (URISyntaxException e) {
+      invokeHandleError(delegate, e);
+      return;
+    }
+
+    resource.delegate = new ResourceDelegate<ExtendedJSONObject>(resource, delegate) {
+      @Override
+      public AuthHeaderProvider getAuthHeaderProvider() {
+        return new BearerAuthHeaderProvider(token);
+      }
+
+      @Override
+      public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+        try {
+          delegate.handleSuccess(body);
+          return;
+        } catch (Exception e) {
+          delegate.handleError(e);
+          return;
+        }
+      }
+    };
+
+    resource.get();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/nativecode/NativeCrypto.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/nativecode/NativeCrypto.java
new file mode 100644
index 000000000..25f0f84d9
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/nativecode/NativeCrypto.java
@@ -0,0 +1,60 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.background.nativecode;
+
+import java.security.GeneralSecurityException;
+
+import org.mozilla.gecko.annotation.RobocopTarget;
+import org.mozilla.gecko.AppConstants;
+
+import android.util.Log;
+
+@RobocopTarget
+public class NativeCrypto {
+  static {
+    try {
+      System.loadLibrary("mozglue");
+    } catch (UnsatisfiedLinkError e) {
+      Log.wtf("NativeCrypto", "Couldn't load mozglue. Trying /data/app-lib path.");
+      try {
+        System.load("/data/app-lib/" + AppConstants.ANDROID_PACKAGE_NAME + "/libmozglue.so");
+      } catch (Throwable ee) {
+          try {
+            Log.wtf("NativeCrypto", "Couldn't load mozglue: " + ee + ". Trying /data/data path.");
+            System.load("/data/data/" + AppConstants.ANDROID_PACKAGE_NAME + "/lib/libmozglue.so");
+          } catch (UnsatisfiedLinkError eee) {
+              Log.wtf("NativeCrypto", "Failed every attempt to load mozglue. Giving up.");
+              throw new RuntimeException("Unable to load mozglue", eee);
+          }
+      }
+    }
+  }
+
+  /**
+   * Wrapper to perform PBKDF2-HMAC-SHA-256 in native code.
+   */
+  public native static byte[] pbkdf2SHA256(byte[] password, byte[] salt, int c, int dkLen)
+      throws GeneralSecurityException;
+
+  /**
+   * Wrapper to perform SHA-1 in native code.
+   */
+  public native static byte[] sha1(byte[] str);
+
+  /**
+   * Wrapper to perform SHA-256 init in native code. Returns a SHA-256 context.
+   */
+  public native static byte[] sha256init();
+
+  /**
+   * Wrapper to update a SHA-256 context in native code.
+   */
+  public native static void sha256update(byte[] ctx, byte[] str, int len);
+
+  /**
+   * Wrapper to finalize a SHA-256 context in native code. Returns digest.
+   */
+  public native static byte[] sha256finalize(byte[] ctx);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/preferences/PreferenceFragment.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/preferences/PreferenceFragment.java
new file mode 100644
index 000000000..5bc5422c8
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/preferences/PreferenceFragment.java
@@ -0,0 +1,326 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.mozilla.gecko.background.preferences;
+
+import org.mozilla.gecko.R;
+import org.mozilla.gecko.util.WeakReferenceHandler;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.Message;
+import android.preference.Preference;
+import android.preference.PreferenceGroup;
+import android.preference.PreferenceManager;
+import android.preference.PreferenceScreen;
+import android.support.v4.app.Fragment;
+import android.view.KeyEvent;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.View.OnKeyListener;
+import android.view.ViewGroup;
+import android.widget.ListView;
+
+public abstract class PreferenceFragment extends Fragment implements PreferenceManagerCompat.OnPreferenceTreeClickListener {
+  private static final String PREFERENCES_TAG = "android:preferences";
+
+  private PreferenceManager mPreferenceManager;
+  private ListView mList;
+  private boolean mHavePrefs;
+  private boolean mInitDone;
+
+  /**
+   * The starting request code given out to preference framework.
+   */
+  private static final int FIRST_REQUEST_CODE = 100;
+
+  private static final int MSG_BIND_PREFERENCES = 1;
+
+  private static class PreferenceFragmentHandler extends WeakReferenceHandler<PreferenceFragment> {
+    public PreferenceFragmentHandler(final PreferenceFragment that) {
+      super(that);
+    }
+
+    @Override
+    public void handleMessage(Message msg) {
+      final PreferenceFragment that = mTarget.get();
+      if (that == null) {
+        return;
+      }
+
+      switch (msg.what) {
+
+      case MSG_BIND_PREFERENCES:
+        that.bindPreferences();
+        break;
+      }
+    }
+  }
+
+  private final Handler mHandler = new PreferenceFragmentHandler(this);
+
+  final private Runnable mRequestFocus = new Runnable() {
+    @Override
+    public void run() {
+      mList.focusableViewAvailable(mList);
+    }
+  };
+
+  /**
+   * Interface that PreferenceFragment's containing activity should
+   * implement to be able to process preference items that wish to
+   * switch to a new fragment.
+   */
+  public interface OnPreferenceStartFragmentCallback {
+    /**
+     * Called when the user has clicked on a Preference that has
+     * a fragment class name associated with it.  The implementation
+     * to should instantiate and switch to an instance of the given
+     * fragment.
+     */
+    boolean onPreferenceStartFragment(PreferenceFragment caller, Preference pref);
+  }
+
+  @Override
+  public void onCreate(Bundle paramBundle) {
+    super.onCreate(paramBundle);
+    mPreferenceManager = PreferenceManagerCompat.newInstance(getActivity(), FIRST_REQUEST_CODE);
+    PreferenceManagerCompat.setFragment(mPreferenceManager, this);
+  }
+
+  @Override
+  public View onCreateView(LayoutInflater paramLayoutInflater, ViewGroup paramViewGroup, Bundle paramBundle) {
+    return paramLayoutInflater.inflate(R.layout.fxaccount_preference_list_fragment, paramViewGroup,
+        false);
+  }
+
+  @Override
+  public void onActivityCreated(Bundle savedInstanceState) {
+    super.onActivityCreated(savedInstanceState);
+
+    if (mHavePrefs) {
+      bindPreferences();
+    }
+
+    mInitDone = true;
+
+    if (savedInstanceState != null) {
+      Bundle container = savedInstanceState.getBundle(PREFERENCES_TAG);
+      if (container != null) {
+        final PreferenceScreen preferenceScreen = getPreferenceScreen();
+        if (preferenceScreen != null) {
+          preferenceScreen.restoreHierarchyState(container);
+        }
+      }
+    }
+  }
+
+  @Override
+  public void onStart() {
+    super.onStart();
+    PreferenceManagerCompat.setOnPreferenceTreeClickListener(mPreferenceManager, this);
+  }
+
+  @Override
+  public void onStop() {
+    super.onStop();
+    PreferenceManagerCompat.dispatchActivityStop(mPreferenceManager);
+    PreferenceManagerCompat.setOnPreferenceTreeClickListener(mPreferenceManager, null);
+  }
+
+  @Override
+  public void onDestroyView() {
+    mList = null;
+    mHandler.removeCallbacks(mRequestFocus);
+    mHandler.removeMessages(MSG_BIND_PREFERENCES);
+    super.onDestroyView();
+  }
+
+  @Override
+  public void onDestroy() {
+    super.onDestroy();
+    PreferenceManagerCompat.dispatchActivityDestroy(mPreferenceManager);
+  }
+
+  @Override
+  public void onSaveInstanceState(Bundle outState) {
+    super.onSaveInstanceState(outState);
+
+    final PreferenceScreen preferenceScreen = getPreferenceScreen();
+    if (preferenceScreen != null) {
+      Bundle container = new Bundle();
+      preferenceScreen.saveHierarchyState(container);
+      outState.putBundle(PREFERENCES_TAG, container);
+    }
+  }
+
+  @Override
+  public void onActivityResult(int requestCode, int resultCode, Intent data) {
+    super.onActivityResult(requestCode, resultCode, data);
+
+    PreferenceManagerCompat.dispatchActivityResult(mPreferenceManager, requestCode, resultCode, data);
+  }
+
+  /**
+   * Returns the {@link PreferenceManager} used by this fragment.
+   * @return The {@link PreferenceManager}.
+   */
+  public PreferenceManager getPreferenceManager() {
+    return mPreferenceManager;
+  }
+
+  /**
+   * Sets the root of the preference hierarchy that this fragment is showing.
+   *
+   * @param preferenceScreen The root {@link PreferenceScreen} of the preference hierarchy.
+   */
+  public void setPreferenceScreen(PreferenceScreen preferenceScreen) {
+    if (PreferenceManagerCompat.setPreferences(mPreferenceManager, preferenceScreen) && preferenceScreen != null) {
+      mHavePrefs = true;
+      if (mInitDone) {
+        postBindPreferences();
+      }
+    }
+  }
+
+  /**
+   * Gets the root of the preference hierarchy that this fragment is showing.
+   *
+   * @return The {@link PreferenceScreen} that is the root of the preference
+   *         hierarchy.
+   */
+  public PreferenceScreen getPreferenceScreen() {
+    return PreferenceManagerCompat.getPreferenceScreen(mPreferenceManager);
+  }
+
+  /**
+   * Adds preferences from activities that match the given {@link Intent}.
+   *
+   * @param intent The {@link Intent} to query activities.
+   */
+  public void addPreferencesFromIntent(Intent intent) {
+    requirePreferenceManager();
+
+    setPreferenceScreen(PreferenceManagerCompat.inflateFromIntent(mPreferenceManager, intent, getPreferenceScreen()));
+  }
+
+  /**
+   * Inflates the given XML resource and adds the preference hierarchy to the current
+   * preference hierarchy.
+   *
+   * @param preferencesResId The XML resource ID to inflate.
+   */
+  public void addPreferencesFromResource(int preferencesResId) {
+    requirePreferenceManager();
+
+    setPreferenceScreen(PreferenceManagerCompat.inflateFromResource(mPreferenceManager, getActivity(),
+        preferencesResId, getPreferenceScreen()));
+  }
+
+  /**
+   * {@inheritDoc}
+   */
+  @Override
+  public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen,
+      Preference preference) {
+    //if (preference.getFragment() != null &&
+    if (
+        getActivity() instanceof OnPreferenceStartFragmentCallback) {
+      return ((OnPreferenceStartFragmentCallback)getActivity()).onPreferenceStartFragment(
+          this, preference);
+    }
+    return false;
+  }
+
+  /**
+   * Finds a {@link Preference} based on its key.
+   *
+   * @param key The key of the preference to retrieve.
+   * @return The {@link Preference} with the key, or null.
+   * @see PreferenceGroup#findPreference(CharSequence)
+   */
+  public Preference findPreference(CharSequence key) {
+    if (mPreferenceManager == null) {
+      return null;
+    }
+    return mPreferenceManager.findPreference(key);
+  }
+
+  private void requirePreferenceManager() {
+    if (mPreferenceManager == null) {
+      throw new RuntimeException("This should be called after super.onCreate.");
+    }
+  }
+
+  private void postBindPreferences() {
+    if (mHandler.hasMessages(MSG_BIND_PREFERENCES)) return;
+    mHandler.obtainMessage(MSG_BIND_PREFERENCES).sendToTarget();
+  }
+
+  private void bindPreferences() {
+    final PreferenceScreen preferenceScreen = getPreferenceScreen();
+    if (preferenceScreen != null) {
+      preferenceScreen.bind(getListView());
+    }
+  }
+
+  public ListView getListView() {
+    ensureList();
+    return mList;
+  }
+
+  private void ensureList() {
+    if (mList != null) {
+      return;
+    }
+    View root = getView();
+    if (root == null) {
+      throw new IllegalStateException("Content view not yet created");
+    }
+    View rawListView = root.findViewById(android.R.id.list);
+    if (!(rawListView instanceof ListView)) {
+      throw new RuntimeException(
+          "Content has view with id attribute 'android.R.id.list' "
+              + "that is not a ListView class");
+    }
+    mList = (ListView)rawListView;
+    if (mList == null) {
+      throw new RuntimeException(
+          "Your content must have a ListView whose id attribute is " +
+          "'android.R.id.list'");
+    }
+    mList.setOnKeyListener(mListOnKeyListener);
+    mHandler.post(mRequestFocus);
+  }
+
+  private final OnKeyListener mListOnKeyListener = new OnKeyListener() {
+
+    @Override
+    public boolean onKey(View v, int keyCode, KeyEvent event) {
+      Object selectedItem = mList.getSelectedItem();
+      if (selectedItem instanceof Preference) {
+        @SuppressWarnings("unused")
+        View selectedView = mList.getSelectedView();
+        //return ((Preference)selectedItem).onKey(
+        //        selectedView, keyCode, event);
+        return false;
+      }
+      return false;
+    }
+
+  };
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/background/preferences/PreferenceManagerCompat.java b/mobile/android/services/src/main/java/org/mozilla/gecko/background/preferences/PreferenceManagerCompat.java
new file mode 100644
index 000000000..22c62e431
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/background/preferences/PreferenceManagerCompat.java
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.mozilla.gecko.background.preferences;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.Intent;
+import android.preference.Preference;
+import android.preference.PreferenceManager;
+import android.preference.PreferenceScreen;
+import android.util.Log;
+
+public class PreferenceManagerCompat {
+
+  private static final String TAG = PreferenceManagerCompat.class.getSimpleName();
+
+  /**
+   * Interface definition for a callback to be invoked when a {@link Preference} in the hierarchy
+   * rooted at this {@link PreferenceScreen} is clicked.
+   */
+  interface OnPreferenceTreeClickListener {
+    /**
+     * Called when a preference in the tree rooted at this {@link PreferenceScreen} has been
+     * clicked.
+     *
+     * @param preferenceScreen The {@link PreferenceScreen} that the preference is located in.
+     * @param preference       The preference that was clicked.
+     *
+     * @return Whether the click was handled.
+     */
+    boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, Preference preference);
+  }
+
+  static PreferenceManager newInstance(Activity activity, int firstRequestCode) {
+    try {
+      Constructor<PreferenceManager> c = PreferenceManager.class.getDeclaredConstructor(Activity.class, int.class);
+      c.setAccessible(true);
+      return c.newInstance(activity, firstRequestCode);
+    } catch (Exception e) {
+      Log.w(TAG, "Couldn't call constructor PreferenceManager by reflection", e);
+    }
+    return null;
+  }
+
+  /**
+   * Sets the owning preference fragment
+   */
+  static void setFragment(PreferenceManager manager, PreferenceFragment fragment) {
+    // stub
+  }
+
+  /**
+   * Sets the callback to be invoked when a {@link Preference} in the hierarchy rooted at this
+   * {@link PreferenceManager} is clicked.
+   *
+   * @param listener The callback to be invoked.
+   */
+  static void setOnPreferenceTreeClickListener(PreferenceManager manager, final OnPreferenceTreeClickListener listener) {
+    try {
+      Field onPreferenceTreeClickListener = PreferenceManager.class.getDeclaredField("mOnPreferenceTreeClickListener");
+      onPreferenceTreeClickListener.setAccessible(true);
+      if (listener != null) {
+        Object proxy = Proxy.newProxyInstance(
+          onPreferenceTreeClickListener.getType().getClassLoader(),
+          new Class<?>[] { onPreferenceTreeClickListener.getType() },
+          new InvocationHandler() {
+            @Override
+            public Object invoke(Object proxy, Method method, Object[] args) {
+              if (method.getName().equals("onPreferenceTreeClick")) {
+                return listener.onPreferenceTreeClick((PreferenceScreen) args[0], (Preference) args[1]);
+              } else {
+                return null;
+              }
+            }
+          });
+        onPreferenceTreeClickListener.set(manager, proxy);
+      } else {
+        onPreferenceTreeClickListener.set(manager, null);
+      }
+    } catch (Exception e) {
+      Log.w(TAG, "Couldn't set PreferenceManager.mOnPreferenceTreeClickListener by reflection", e);
+    }
+  }
+
+  /**
+   * Inflates a preference hierarchy from the preference hierarchies of {@link Activity Activities}
+   * that match the given {@link Intent}. An {@link Activity} defines its preference hierarchy with
+   * meta-data using the {@link #METADATA_KEY_PREFERENCES} key.
+   * <p/>
+   * If a preference hierarchy is given, the new preference hierarchies will be merged in.
+   *
+   * @param queryIntent     The intent to match activities.
+   * @param rootPreferences Optional existing hierarchy to merge the new hierarchies into.
+   *
+   * @return The root hierarchy (if one was not provided, the new hierarchy's root).
+   */
+  static PreferenceScreen inflateFromIntent(PreferenceManager manager, Intent intent, PreferenceScreen screen) {
+    try {
+      Method m = PreferenceManager.class.getDeclaredMethod("inflateFromIntent", Intent.class, PreferenceScreen.class);
+      m.setAccessible(true);
+      PreferenceScreen prefScreen = (PreferenceScreen) m.invoke(manager, intent, screen);
+      return prefScreen;
+    } catch (Exception e) {
+      Log.w(TAG, "Couldn't call PreferenceManager.inflateFromIntent by reflection", e);
+    }
+    return null;
+  }
+
+  /**
+   * Inflates a preference hierarchy from XML. If a preference hierarchy is given, the new
+   * preference hierarchies will be merged in.
+   *
+   * @param context         The context of the resource.
+   * @param resId           The resource ID of the XML to inflate.
+   * @param rootPreferences Optional existing hierarchy to merge the new hierarchies into.
+   *
+   * @return The root hierarchy (if one was not provided, the new hierarchy's root).
+   *
+   * @hide
+   */
+  static PreferenceScreen inflateFromResource(PreferenceManager manager, Activity activity, int resId, PreferenceScreen screen) {
+    try {
+      Method m = PreferenceManager.class.getDeclaredMethod("inflateFromResource", Context.class, int.class, PreferenceScreen.class);
+      m.setAccessible(true);
+      PreferenceScreen prefScreen = (PreferenceScreen) m.invoke(manager, activity, resId, screen);
+      return prefScreen;
+    } catch (Exception e) {
+      Log.w(TAG, "Couldn't call PreferenceManager.inflateFromResource by reflection", e);
+    }
+    return null;
+  }
+
+  /**
+   * Returns the root of the preference hierarchy managed by this class.
+   *
+   * @return The {@link PreferenceScreen} object that is at the root of the hierarchy.
+   */
+  static PreferenceScreen getPreferenceScreen(PreferenceManager manager) {
+    try {
+      Method m = PreferenceManager.class.getDeclaredMethod("getPreferenceScreen");
+      m.setAccessible(true);
+      return (PreferenceScreen) m.invoke(manager);
+    } catch (Exception e) {
+      Log.w(TAG, "Couldn't call PreferenceManager.getPreferenceScreen by reflection", e);
+    }
+    return null;
+  }
+
+  /**
+   * Called by the {@link PreferenceManager} to dispatch a subactivity result.
+   */
+  static void dispatchActivityResult(PreferenceManager manager, int requestCode, int resultCode, Intent data) {
+    try {
+      Method m = PreferenceManager.class.getDeclaredMethod("dispatchActivityResult", int.class, int.class, Intent.class);
+      m.setAccessible(true);
+      m.invoke(manager, requestCode, resultCode, data);
+    } catch (Exception e) {
+      Log.w(TAG, "Couldn't call PreferenceManager.dispatchActivityResult by reflection", e);
+    }
+  }
+
+  /**
+   * Called by the {@link PreferenceManager} to dispatch the activity stop event.
+   */
+  static void dispatchActivityStop(PreferenceManager manager) {
+    try {
+      Method m = PreferenceManager.class.getDeclaredMethod("dispatchActivityStop");
+      m.setAccessible(true);
+      m.invoke(manager);
+    } catch (Exception e) {
+      Log.w(TAG, "Couldn't call PreferenceManager.dispatchActivityStop by reflection", e);
+    }
+  }
+
+  /**
+   * Called by the {@link PreferenceManager} to dispatch the activity destroy event.
+   */
+  static void dispatchActivityDestroy(PreferenceManager manager) {
+    try {
+      Method m = PreferenceManager.class.getDeclaredMethod("dispatchActivityDestroy");
+      m.setAccessible(true);
+      m.invoke(manager);
+    } catch (Exception e) {
+      Log.w(TAG, "Couldn't call PreferenceManager.dispatchActivityDestroy by reflection", e);
+    }
+  }
+
+  /**
+   * Sets the root of the preference hierarchy.
+   *
+   * @param preferenceScreen The root {@link PreferenceScreen} of the preference hierarchy.
+   *
+   * @return Whether the {@link PreferenceScreen} given is different than the previous.
+   */
+  static boolean setPreferences(PreferenceManager manager, PreferenceScreen screen) {
+    try {
+      Method m = PreferenceManager.class.getDeclaredMethod("setPreferences", PreferenceScreen.class);
+      m.setAccessible(true);
+      return ((Boolean) m.invoke(manager, screen));
+    } catch (Exception e) {
+      Log.w(TAG, "Couldn't call PreferenceManager.setPreferences by reflection", e);
+    }
+    return false;
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/ASNUtils.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/ASNUtils.java
new file mode 100644
index 000000000..b032067c5
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/ASNUtils.java
@@ -0,0 +1,82 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid;
+
+
+/**
+ * Java produces signature in ASN.1 format. Here's some hard-coded encoding and decoding
+ * code, courtesy of a comment in
+ * <a href="http://stackoverflow.com/questions/10921733/how-sign-method-of-the-digital-signature-combines-the-r-s-values-in-to-array">http://stackoverflow.com/questions/10921733/how-sign-method-of-the-digital-signature-combines-the-r-s-values-in-to-array</a>.
+ */
+public class ASNUtils {
+  /**
+   * Decode two short arrays from ASN.1 bytes.
+   * @param input to extract.
+   * @return length 2 array of byte arrays.
+   */
+  public static byte[][] decodeTwoArraysFromASN1(byte[] input) throws IllegalArgumentException {
+    if (input == null) {
+      throw new IllegalArgumentException("input must not be null");
+    }
+    if (input.length <= 3)
+      throw new IllegalArgumentException("bad length");
+    if (input[0] != 0x30)
+      throw new IllegalArgumentException("bad encoding");
+    if ((input[1] & ((byte) 0x80)) != 0)
+      throw new IllegalArgumentException("bad length encoding");
+    if (input[2] != 0x02)
+      throw new IllegalArgumentException("bad encoding");
+    if ((input[3] & ((byte) 0x80)) != 0)
+      throw new IllegalArgumentException("bad length encoding");
+    byte rLength = input[3];
+    if (input.length <= 5 + rLength)
+      throw new IllegalArgumentException("bad length");
+    if (input[4 + rLength] != 0x02)
+      throw new IllegalArgumentException("bad encoding");
+    if ((input[5 + rLength] & (byte) 0x80) !=0)
+      throw new IllegalArgumentException("bad length encoding");
+    byte sLength = input[5 + rLength];
+    if (input.length != 6 + sLength + rLength)
+      throw new IllegalArgumentException("bad length");
+    byte[] rArr = new byte[rLength];
+    byte[] sArr = new byte[sLength];
+    System.arraycopy(input, 4, rArr, 0, rLength);
+    System.arraycopy(input, 6 + rLength, sArr, 0, sLength);
+    return new byte[][] { rArr, sArr };
+  }
+
+  /**
+   * Encode two short arrays into ASN.1 bytes.
+   * @param first array to encode.
+   * @param second array to encode.
+   * @return array.
+   */
+  public static byte[] encodeTwoArraysToASN1(byte[] first, byte[] second) throws IllegalArgumentException {
+    if (first == null) {
+      throw new IllegalArgumentException("first must not be null");
+    }
+    if (second == null) {
+      throw new IllegalArgumentException("second must not be null");
+    }
+    byte[] output = new byte[6 + first.length + second.length];
+    output[0] = 0x30;
+    if (4 + first.length + second.length > 255)
+      throw new IllegalArgumentException("bad length");
+    output[1] = (byte) (4 + first.length + second.length);
+    if ((output[1] & ((byte) 0x80)) != 0)
+      throw new IllegalArgumentException("bad length encoding");
+    output[2] = 0x02;
+    output[3] = (byte) first.length;
+    if ((output[3] & ((byte) 0x80)) != 0)
+      throw new IllegalArgumentException("bad length encoding");
+    System.arraycopy(first, 0, output, 4, first.length);
+    output[4 + first.length] = 0x02;
+    output[5 + first.length] = (byte) second.length;
+    if ((output[5 + first.length] & ((byte) 0x80)) != 0)
+      throw new IllegalArgumentException("bad length encoding");
+    System.arraycopy(second, 0, output, 6 + first.length, second.length);
+    return output;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/BrowserIDKeyPair.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/BrowserIDKeyPair.java
new file mode 100644
index 000000000..7283a0299
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/BrowserIDKeyPair.java
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+public class BrowserIDKeyPair {
+  public static final String JSON_KEY_PRIVATEKEY = "privateKey";
+  public static final String JSON_KEY_PUBLICKEY = "publicKey";
+
+  protected final SigningPrivateKey privateKey;
+  protected final VerifyingPublicKey publicKey;
+
+  public BrowserIDKeyPair(SigningPrivateKey privateKey, VerifyingPublicKey publicKey) {
+    this.privateKey = privateKey;
+    this.publicKey = publicKey;
+  }
+
+  public SigningPrivateKey getPrivate() {
+    return this.privateKey;
+  }
+
+  public VerifyingPublicKey getPublic() {
+    return this.publicKey;
+  }
+
+  public ExtendedJSONObject toJSONObject() {
+    ExtendedJSONObject o = new ExtendedJSONObject();
+    o.put(JSON_KEY_PRIVATEKEY, privateKey.toJSONObject());
+    o.put(JSON_KEY_PUBLICKEY, publicKey.toJSONObject());
+    return o;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/DSACryptoImplementation.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/DSACryptoImplementation.java
new file mode 100644
index 000000000..a04a89c8e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/DSACryptoImplementation.java
@@ -0,0 +1,255 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid;
+
+import android.annotation.SuppressLint;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.util.PRNGFixes;
+
+import java.math.BigInteger;
+import java.security.GeneralSecurityException;
+import java.security.KeyFactory;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.NoSuchAlgorithmException;
+import java.security.Signature;
+import java.security.interfaces.DSAParams;
+import java.security.interfaces.DSAPrivateKey;
+import java.security.interfaces.DSAPublicKey;
+import java.security.spec.DSAPrivateKeySpec;
+import java.security.spec.DSAPublicKeySpec;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.KeySpec;
+
+public class DSACryptoImplementation {
+  private static final String LOG_TAG = DSACryptoImplementation.class.getSimpleName();
+
+  public static final String SIGNATURE_ALGORITHM = "SHA1withDSA";
+  public static final int SIGNATURE_LENGTH_BYTES = 40; // DSA signatures are always 40 bytes long.
+
+  /**
+   * Parameters are serialized as hex strings. Hex-versus-decimal was
+   * reverse-engineered from what the Persona public verifier accepted. We
+   * expect to follow the JOSE/JWT spec as it solidifies, and that will probably
+   * mean unifying this base.
+   */
+  protected static final int SERIALIZATION_BASE = 16;
+
+  protected static class DSAVerifyingPublicKey implements VerifyingPublicKey {
+    protected final DSAPublicKey publicKey;
+
+    public DSAVerifyingPublicKey(DSAPublicKey publicKey) {
+      this.publicKey = publicKey;
+    }
+
+    /**
+     * Serialize to a JSON object.
+     * <p>
+     * Parameters are serialized as hex strings. Hex-versus-decimal was
+     * reverse-engineered from what the Persona public verifier accepted.
+     */
+    @Override
+    public ExtendedJSONObject toJSONObject() {
+      DSAParams params = publicKey.getParams();
+      ExtendedJSONObject o = new ExtendedJSONObject();
+      o.put("algorithm", "DS");
+      o.put("y", publicKey.getY().toString(SERIALIZATION_BASE));
+      o.put("g", params.getG().toString(SERIALIZATION_BASE));
+      o.put("p", params.getP().toString(SERIALIZATION_BASE));
+      o.put("q", params.getQ().toString(SERIALIZATION_BASE));
+      return o;
+    }
+
+    @Override
+    public boolean verifyMessage(byte[] bytes, byte[] signature)
+        throws GeneralSecurityException {
+      if (bytes == null) {
+        throw new IllegalArgumentException("bytes must not be null");
+      }
+      if (signature == null) {
+        throw new IllegalArgumentException("signature must not be null");
+      }
+      if (signature.length != SIGNATURE_LENGTH_BYTES) {
+        return false;
+      }
+      byte[] first = new byte[signature.length / 2];
+      byte[] second = new byte[signature.length / 2];
+      System.arraycopy(signature, 0, first, 0, first.length);
+      System.arraycopy(signature, first.length, second, 0, second.length);
+      BigInteger r = new BigInteger(Utils.byte2Hex(first), 16);
+      BigInteger s = new BigInteger(Utils.byte2Hex(second), 16);
+      // This is awful, but encoding an extra 0 byte works better on devices.
+      byte[] encoded = ASNUtils.encodeTwoArraysToASN1(
+          Utils.hex2Byte(r.toString(16), 1 + SIGNATURE_LENGTH_BYTES / 2),
+          Utils.hex2Byte(s.toString(16), 1 + SIGNATURE_LENGTH_BYTES / 2));
+
+      final Signature signer = Signature.getInstance(SIGNATURE_ALGORITHM);
+      signer.initVerify(publicKey);
+      signer.update(bytes);
+      return signer.verify(encoded);
+    }
+  }
+
+  protected static class DSASigningPrivateKey implements SigningPrivateKey {
+    protected final DSAPrivateKey privateKey;
+
+    public DSASigningPrivateKey(DSAPrivateKey privateKey) {
+      this.privateKey = privateKey;
+    }
+
+    @Override
+    public String getAlgorithm() {
+      return "DS" + (privateKey.getParams().getP().bitLength() + 7)/8;
+    }
+
+    /**
+     * Serialize to a JSON object.
+     * <p>
+     * Parameters are serialized as decimal strings. Hex-versus-decimal was
+     * reverse-engineered from what the Persona public verifier accepted.
+     */
+    @Override
+    public ExtendedJSONObject toJSONObject() {
+      DSAParams params = privateKey.getParams();
+      ExtendedJSONObject o = new ExtendedJSONObject();
+      o.put("algorithm", "DS");
+      o.put("x", privateKey.getX().toString(SERIALIZATION_BASE));
+      o.put("g", params.getG().toString(SERIALIZATION_BASE));
+      o.put("p", params.getP().toString(SERIALIZATION_BASE));
+      o.put("q", params.getQ().toString(SERIALIZATION_BASE));
+      return o;
+    }
+
+    @SuppressLint("TrulyRandom")
+    @Override
+    public byte[] signMessage(byte[] bytes)
+        throws GeneralSecurityException {
+      if (bytes == null) {
+        throw new IllegalArgumentException("bytes must not be null");
+      }
+
+      try {
+        PRNGFixes.apply();
+      } catch (Exception e) {
+        // Not much to be done here: it was weak before, and we couldn't patch it, so it's weak now.  Not worth aborting.
+        Logger.error(LOG_TAG, "Got exception applying PRNGFixes!  Cryptographic data produced on this device may be weak.  Ignoring.", e);
+      }
+
+      final Signature signer = Signature.getInstance(SIGNATURE_ALGORITHM);
+      signer.initSign(privateKey);
+      signer.update(bytes);
+      final byte[] signature = signer.sign();
+
+      final byte[][] arrays = ASNUtils.decodeTwoArraysFromASN1(signature);
+      BigInteger r = new BigInteger(arrays[0]);
+      BigInteger s = new BigInteger(arrays[1]);
+      // This is awful, but signatures are always 40 bytes long.
+      byte[] decoded = Utils.concatAll(
+          Utils.hex2Byte(r.toString(16), SIGNATURE_LENGTH_BYTES / 2),
+          Utils.hex2Byte(s.toString(16), SIGNATURE_LENGTH_BYTES / 2));
+      return decoded;
+    }
+  }
+
+  public static BrowserIDKeyPair generateKeyPair(int keysize)
+      throws NoSuchAlgorithmException {
+    final KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("DSA");
+    keyPairGenerator.initialize(keysize);
+    final KeyPair keyPair = keyPairGenerator.generateKeyPair();
+    DSAPrivateKey privateKey = (DSAPrivateKey) keyPair.getPrivate();
+    DSAPublicKey publicKey = (DSAPublicKey) keyPair.getPublic();
+    return new BrowserIDKeyPair(new DSASigningPrivateKey(privateKey), new DSAVerifyingPublicKey(publicKey));
+  }
+
+  public static SigningPrivateKey createPrivateKey(BigInteger x, BigInteger p, BigInteger q, BigInteger g) throws NoSuchAlgorithmException, InvalidKeySpecException {
+    if (x == null) {
+      throw new IllegalArgumentException("x must not be null");
+    }
+    if (p == null) {
+      throw new IllegalArgumentException("p must not be null");
+    }
+    if (q == null) {
+      throw new IllegalArgumentException("q must not be null");
+    }
+    if (g == null) {
+      throw new IllegalArgumentException("g must not be null");
+    }
+    KeySpec keySpec = new DSAPrivateKeySpec(x, p, q, g);
+    KeyFactory keyFactory = KeyFactory.getInstance("DSA");
+    DSAPrivateKey privateKey = (DSAPrivateKey) keyFactory.generatePrivate(keySpec);
+    return new DSASigningPrivateKey(privateKey);
+  }
+
+  public static VerifyingPublicKey createPublicKey(BigInteger y, BigInteger p, BigInteger q, BigInteger g) throws NoSuchAlgorithmException, InvalidKeySpecException {
+    if (y == null) {
+      throw new IllegalArgumentException("n must not be null");
+    }
+    if (p == null) {
+      throw new IllegalArgumentException("p must not be null");
+    }
+    if (q == null) {
+      throw new IllegalArgumentException("q must not be null");
+    }
+    if (g == null) {
+      throw new IllegalArgumentException("g must not be null");
+    }
+    KeySpec keySpec = new DSAPublicKeySpec(y, p, q, g);
+    KeyFactory keyFactory = KeyFactory.getInstance("DSA");
+    DSAPublicKey publicKey = (DSAPublicKey) keyFactory.generatePublic(keySpec);
+    return new DSAVerifyingPublicKey(publicKey);
+  }
+
+  public static SigningPrivateKey createPrivateKey(ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    String algorithm = o.getString("algorithm");
+    if (!"DS".equals(algorithm)) {
+      throw new InvalidKeySpecException("algorithm must equal DS, was " + algorithm);
+    }
+    try {
+      BigInteger x = new BigInteger(o.getString("x"), SERIALIZATION_BASE);
+      BigInteger p = new BigInteger(o.getString("p"), SERIALIZATION_BASE);
+      BigInteger q = new BigInteger(o.getString("q"), SERIALIZATION_BASE);
+      BigInteger g = new BigInteger(o.getString("g"), SERIALIZATION_BASE);
+      return createPrivateKey(x, p, q, g);
+    } catch (NullPointerException | NumberFormatException e) {
+      throw new InvalidKeySpecException("x, p, q, and g must be integers encoded as strings, base " + SERIALIZATION_BASE);
+    }
+  }
+
+  public static VerifyingPublicKey createPublicKey(ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    String algorithm = o.getString("algorithm");
+    if (!"DS".equals(algorithm)) {
+      throw new InvalidKeySpecException("algorithm must equal DS, was " + algorithm);
+    }
+    try {
+      BigInteger y = new BigInteger(o.getString("y"), SERIALIZATION_BASE);
+      BigInteger p = new BigInteger(o.getString("p"), SERIALIZATION_BASE);
+      BigInteger q = new BigInteger(o.getString("q"), SERIALIZATION_BASE);
+      BigInteger g = new BigInteger(o.getString("g"), SERIALIZATION_BASE);
+      return createPublicKey(y, p, q, g);
+    } catch (NullPointerException | NumberFormatException e) {
+      throw new InvalidKeySpecException("y, p, q, and g must be integers encoded as strings, base " + SERIALIZATION_BASE);
+    }
+  }
+
+  public static BrowserIDKeyPair fromJSONObject(ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    try {
+      ExtendedJSONObject privateKey = o.getObject(BrowserIDKeyPair.JSON_KEY_PRIVATEKEY);
+      ExtendedJSONObject publicKey = o.getObject(BrowserIDKeyPair.JSON_KEY_PUBLICKEY);
+      if (privateKey == null) {
+        throw new InvalidKeySpecException("privateKey must not be null");
+      }
+      if (publicKey == null) {
+        throw new InvalidKeySpecException("publicKey must not be null");
+      }
+      return new BrowserIDKeyPair(createPrivateKey(privateKey), createPublicKey(publicKey));
+    } catch (NonObjectJSONException e) {
+      throw new InvalidKeySpecException("privateKey and publicKey must be JSON objects");
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/JSONWebTokenUtils.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/JSONWebTokenUtils.java
new file mode 100644
index 000000000..207accc76
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/JSONWebTokenUtils.java
@@ -0,0 +1,245 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid;
+
+import org.json.simple.JSONObject;
+import org.mozilla.apache.commons.codec.binary.Base64;
+import org.mozilla.apache.commons.codec.binary.StringUtils;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+import org.mozilla.gecko.sync.Utils;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.security.GeneralSecurityException;
+import java.util.ArrayList;
+import java.util.TreeMap;
+
+/**
+ * Encode and decode JSON Web Tokens.
+ * <p>
+ * Reverse-engineered from the Node.js jwcrypto library at
+ * <a href="https://github.com/mozilla/jwcrypto">https://github.com/mozilla/jwcrypto</a>
+ * and informed by the informal draft standard "JSON Web Token (JWT)" at
+ * <a href="http://self-issued.info/docs/draft-ietf-oauth-json-web-token.html">http://self-issued.info/docs/draft-ietf-oauth-json-web-token.html</a>.
+ */
+public class JSONWebTokenUtils {
+  public static final long DEFAULT_CERTIFICATE_DURATION_IN_MILLISECONDS = 60 * 60 * 1000;
+  public static final long DEFAULT_ASSERTION_DURATION_IN_MILLISECONDS = 60 * 60 * 1000;
+  public static final long DEFAULT_FUTURE_EXPIRES_AT_IN_MILLISECONDS = 9999999999999L;
+  public static final String DEFAULT_CERTIFICATE_ISSUER = "127.0.0.1";
+  public static final String DEFAULT_ASSERTION_ISSUER = "127.0.0.1";
+
+  public static String encode(String payload, SigningPrivateKey privateKey) throws UnsupportedEncodingException, GeneralSecurityException  {
+    final ExtendedJSONObject header = new ExtendedJSONObject();
+    header.put("alg", privateKey.getAlgorithm());
+    String encodedHeader  = Base64.encodeBase64URLSafeString(header.toJSONString().getBytes("UTF-8"));
+    String encodedPayload = Base64.encodeBase64URLSafeString(payload.getBytes("UTF-8"));
+    ArrayList<String> segments = new ArrayList<String>();
+    segments.add(encodedHeader);
+    segments.add(encodedPayload);
+    byte[] message = Utils.toDelimitedString(".", segments).getBytes("UTF-8");
+    byte[] signature = privateKey.signMessage(message);
+    segments.add(Base64.encodeBase64URLSafeString(signature));
+    return Utils.toDelimitedString(".", segments);
+  }
+
+  public static String decode(String token, VerifyingPublicKey publicKey) throws GeneralSecurityException, UnsupportedEncodingException  {
+    if (token == null) {
+      throw new IllegalArgumentException("token must not be null");
+    }
+    String[] segments = token.split("\\.");
+    if (segments == null || segments.length != 3) {
+      throw new GeneralSecurityException("malformed token");
+    }
+    byte[] message = (segments[0] + "." + segments[1]).getBytes("UTF-8");
+    byte[] signature = Base64.decodeBase64(segments[2]);
+    boolean verifies = publicKey.verifyMessage(message, signature);
+    if (!verifies) {
+      throw new GeneralSecurityException("bad signature");
+    }
+    String payload = StringUtils.newStringUtf8(Base64.decodeBase64(segments[1]));
+    return payload;
+  }
+
+  /**
+   * Public for testing.
+   */
+  @SuppressWarnings("unchecked")
+  public static String getPayloadString(String payloadString, String audience, String issuer,
+      Long issuedAt, long expiresAt) throws NonObjectJSONException, IOException {
+    ExtendedJSONObject payload;
+    if (payloadString != null) {
+      payload = new ExtendedJSONObject(payloadString);
+    } else {
+      payload = new ExtendedJSONObject();
+    }
+    if (audience != null) {
+      payload.put("aud", audience);
+    }
+    payload.put("iss", issuer);
+    if (issuedAt != null) {
+      payload.put("iat", issuedAt);
+    }
+    payload.put("exp", expiresAt);
+    // TreeMap so that keys are sorted. A small attempt to keep output stable over time.
+    return JSONObject.toJSONString(new TreeMap<Object, Object>(payload.object));
+  }
+
+  protected static String getCertificatePayloadString(VerifyingPublicKey publicKeyToSign, String email) throws NonObjectJSONException, IOException  {
+    ExtendedJSONObject payload = new ExtendedJSONObject();
+    ExtendedJSONObject principal = new ExtendedJSONObject();
+    principal.put("email", email);
+    payload.put("principal", principal);
+    payload.put("public-key", publicKeyToSign.toJSONObject());
+    return payload.toJSONString();
+  }
+
+  public static String createCertificate(VerifyingPublicKey publicKeyToSign, String email,
+      String issuer, long issuedAt, long expiresAt, SigningPrivateKey privateKey) throws NonObjectJSONException, IOException, GeneralSecurityException  {
+    String certificatePayloadString = getCertificatePayloadString(publicKeyToSign, email);
+    String payloadString = getPayloadString(certificatePayloadString, null, issuer, issuedAt, expiresAt);
+    return JSONWebTokenUtils.encode(payloadString, privateKey);
+  }
+
+  /**
+   * Create a Browser ID assertion.
+   *
+   * @param privateKeyToSignWith
+   *          private key to sign assertion with.
+   * @param certificate
+   *          to include in assertion; no attempt is made to ensure the
+   *          certificate is valid, or corresponds to the private key, or any
+   *          other condition.
+   * @param audience
+   *          to produce assertion for.
+   * @param issuer
+   *          to produce assertion for.
+   * @param issuedAt
+   *          timestamp for assertion, in milliseconds since the epoch; if null,
+   *          no timestamp is included.
+   * @param expiresAt
+   *          expiration timestamp for assertion, in milliseconds since the epoch.
+   * @return assertion.
+   * @throws NonObjectJSONException
+   * @throws IOException
+   * @throws GeneralSecurityException
+   */
+  public static String createAssertion(SigningPrivateKey privateKeyToSignWith, String certificate, String audience,
+      String issuer, Long issuedAt, long expiresAt) throws NonObjectJSONException, IOException, GeneralSecurityException  {
+    String emptyAssertionPayloadString = "{}";
+    String payloadString = getPayloadString(emptyAssertionPayloadString, audience, issuer, issuedAt, expiresAt);
+    String signature = JSONWebTokenUtils.encode(payloadString, privateKeyToSignWith);
+    return certificate + "~" + signature;
+  }
+
+  /**
+   * For debugging only!
+   *
+   * @param input
+   *          certificate to dump.
+   * @return non-null object with keys header, payload, signature if the
+   *         certificate is well-formed.
+   */
+  public static ExtendedJSONObject parseCertificate(String input) {
+    try {
+      String[] parts = input.split("\\.");
+      if (parts.length != 3) {
+        return null;
+      }
+      String cHeader = new String(Base64.decodeBase64(parts[0]));
+      String cPayload = new String(Base64.decodeBase64(parts[1]));
+      String cSignature = Utils.byte2Hex(Base64.decodeBase64(parts[2]));
+      ExtendedJSONObject o = new ExtendedJSONObject();
+      o.put("header", new ExtendedJSONObject(cHeader));
+      o.put("payload", new ExtendedJSONObject(cPayload));
+      o.put("signature", cSignature);
+      return o;
+    } catch (Exception e) {
+      return null;
+    }
+  }
+
+  /**
+   * For debugging only!
+   *
+   * @param input certificate to dump.
+   * @return true if the certificate is well-formed.
+   */
+  public static boolean dumpCertificate(String input) {
+    ExtendedJSONObject c = parseCertificate(input);
+    try {
+      if (c == null) {
+        System.out.println("Malformed certificate -- got exception trying to dump contents.");
+        return false;
+      }
+      System.out.println("certificate header:    " + c.getObject("header").toJSONString());
+      System.out.println("certificate payload:   " + c.getObject("payload").toJSONString());
+      System.out.println("certificate signature: " + c.getString("signature"));
+      return true;
+    } catch (Exception e) {
+      System.out.println("Malformed certificate -- got exception trying to dump contents.");
+      return false;
+    }
+  }
+
+  /**
+   * For debugging only!
+   *
+   * @param input assertion to dump.
+   * @return true if the assertion is well-formed.
+   */
+  public static ExtendedJSONObject parseAssertion(String input) {
+    try {
+      String[] parts = input.split("~");
+      if (parts.length != 2) {
+        return null;
+      }
+      String certificate = parts[0];
+      String assertion = parts[1];
+      parts = assertion.split("\\.");
+      if (parts.length != 3) {
+        return null;
+      }
+      String aHeader = new String(Base64.decodeBase64(parts[0]));
+      String aPayload = new String(Base64.decodeBase64(parts[1]));
+      String aSignature = Utils.byte2Hex(Base64.decodeBase64(parts[2]));
+      // We do all the assertion parsing *before* dumping the certificate in
+      // case there's a malformed assertion.
+      ExtendedJSONObject o = new ExtendedJSONObject();
+      o.put("header", new ExtendedJSONObject(aHeader));
+      o.put("payload", new ExtendedJSONObject(aPayload));
+      o.put("signature", aSignature);
+      o.put("certificate", certificate);
+      return o;
+    } catch (Exception e) {
+      return null;
+    }
+  }
+
+  /**
+   * For debugging only!
+   *
+   * @param input assertion to dump.
+   * @return true if the assertion is well-formed.
+   */
+  public static boolean dumpAssertion(String input) {
+    ExtendedJSONObject a = parseAssertion(input);
+    try {
+      if (a == null) {
+        System.out.println("Malformed assertion -- got exception trying to dump contents.");
+        return false;
+      }
+      dumpCertificate(a.getString("certificate"));
+      System.out.println("assertion   header:    " + a.getObject("header").toJSONString());
+      System.out.println("assertion   payload:   " + a.getObject("payload").toJSONString());
+      System.out.println("assertion   signature: " + a.getString("signature"));
+      return true;
+    } catch (Exception e) {
+      System.out.println("Malformed assertion -- got exception trying to dump contents.");
+      return false;
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/MockMyIDTokenFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/MockMyIDTokenFactory.java
new file mode 100644
index 000000000..c807d4cbb
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/MockMyIDTokenFactory.java
@@ -0,0 +1,128 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid;
+
+import java.math.BigInteger;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+
+/**
+ * Generate certificates and assertions backed by mockmyid.com's private key.
+ * <p>
+ * These artifacts are for testing only.
+ */
+public class MockMyIDTokenFactory {
+  public static final BigInteger MOCKMYID_x = new BigInteger("385cb3509f086e110c5e24bdd395a84b335a09ae", 16);
+  public static final BigInteger MOCKMYID_y = new BigInteger("738ec929b559b604a232a9b55a5295afc368063bb9c20fac4e53a74970a4db7956d48e4c7ed523405f629b4cc83062f13029c4d615bbacb8b97f5e56f0c7ac9bc1d4e23809889fa061425c984061fca1826040c399715ce7ed385c4dd0d402256912451e03452d3c961614eb458f188e3e8d2782916c43dbe2e571251ce38262", 16);
+  public static final BigInteger MOCKMYID_p = new BigInteger("ff600483db6abfc5b45eab78594b3533d550d9f1bf2a992a7a8daa6dc34f8045ad4e6e0c429d334eeeaaefd7e23d4810be00e4cc1492cba325ba81ff2d5a5b305a8d17eb3bf4a06a349d392e00d329744a5179380344e82a18c47933438f891e22aeef812d69c8f75e326cb70ea000c3f776dfdbd604638c2ef717fc26d02e17", 16);
+  public static final BigInteger MOCKMYID_q = new BigInteger("e21e04f911d1ed7991008ecaab3bf775984309c3", 16);
+  public static final BigInteger MOCKMYID_g = new BigInteger("c52a4a0ff3b7e61fdf1867ce84138369a6154f4afa92966e3c827e25cfa6cf508b90e5de419e1337e07a2e9e2a3cd5dea704d175f8ebf6af397d69e110b96afb17c7a03259329e4829b0d03bbc7896b15b4ade53e130858cc34d96269aa89041f409136c7242a38895c9d5bccad4f389af1d7a4bd1398bd072dffa896233397a", 16);
+
+  // Computed lazily by static <code>getMockMyIDPrivateKey</code>.
+  protected static SigningPrivateKey cachedMockMyIDPrivateKey;
+
+  public static SigningPrivateKey getMockMyIDPrivateKey() throws NoSuchAlgorithmException, InvalidKeySpecException {
+    if (cachedMockMyIDPrivateKey == null) {
+      cachedMockMyIDPrivateKey = DSACryptoImplementation.createPrivateKey(MOCKMYID_x, MOCKMYID_p, MOCKMYID_q, MOCKMYID_g);
+    }
+    return cachedMockMyIDPrivateKey;
+  }
+
+  /**
+   * Sign a public key asserting ownership of username@mockmyid.com with
+   * mockmyid.com's private key.
+   *
+   * @param publicKeyToSign
+   *          public key to sign.
+   * @param username
+   *          sign username@mockmyid.com
+   * @param issuedAt
+   *          timestamp for certificate, in milliseconds since the epoch.
+   * @param expiresAt
+   *          expiration timestamp for certificate, in milliseconds since the epoch.
+   * @return encoded certificate string.
+   * @throws Exception
+   */
+  public String createMockMyIDCertificate(final VerifyingPublicKey publicKeyToSign, String username,
+      final long issuedAt, final long expiresAt)
+          throws Exception {
+    if (!username.endsWith("@mockmyid.com")) {
+      username = username + "@mockmyid.com";
+    }
+    SigningPrivateKey mockMyIdPrivateKey = getMockMyIDPrivateKey();
+    return JSONWebTokenUtils.createCertificate(publicKeyToSign, username, "mockmyid.com", issuedAt, expiresAt, mockMyIdPrivateKey);
+  }
+
+  /**
+   * Sign a public key asserting ownership of username@mockmyid.com with
+   * mockmyid.com's private key.
+   *
+   * @param publicKeyToSign
+   *          public key to sign.
+   * @param username
+   *          sign username@mockmyid.com
+   * @return encoded certificate string.
+   * @throws Exception
+   */
+  public String createMockMyIDCertificate(final VerifyingPublicKey publicKeyToSign, final String username)
+      throws Exception {
+    long ciat = System.currentTimeMillis();
+    long cexp = ciat + JSONWebTokenUtils.DEFAULT_CERTIFICATE_DURATION_IN_MILLISECONDS;
+    return createMockMyIDCertificate(publicKeyToSign, username, ciat, cexp);
+  }
+
+  /**
+   * Generate an assertion asserting ownership of username@mockmyid.com to a
+   * relying party. The underlying certificate is signed by mockymid.com's
+   * private key.
+   *
+   * @param keyPair
+   *          to sign with.
+   * @param username
+   *          sign username@mockmyid.com.
+   * @param certificateIssuedAt
+   *          timestamp for certificate, in milliseconds since the epoch.
+   * @param certificateExpiresAt
+   *          expiration timestamp for certificate, in milliseconds since the epoch.
+   * @param assertionIssuedAt
+   *          timestamp for assertion, in milliseconds since the epoch; if null,
+   *          no timestamp is included.
+   * @param assertionExpiresAt
+   *          expiration timestamp for assertion, in milliseconds since the epoch.
+   * @return encoded assertion string.
+   * @throws Exception
+   */
+  public String createMockMyIDAssertion(BrowserIDKeyPair keyPair, String username, String audience,
+      long certificateIssuedAt, long certificateExpiresAt,
+      Long assertionIssuedAt, long assertionExpiresAt)
+          throws Exception {
+    String certificate = createMockMyIDCertificate(keyPair.getPublic(), username,
+        certificateIssuedAt, certificateExpiresAt);
+    return JSONWebTokenUtils.createAssertion(keyPair.getPrivate(), certificate, audience,
+        JSONWebTokenUtils.DEFAULT_ASSERTION_ISSUER, assertionIssuedAt, assertionExpiresAt);
+  }
+
+  /**
+   * Generate an assertion asserting ownership of username@mockmyid.com to a
+   * relying party. The underlying certificate is signed by mockymid.com's
+   * private key.
+   *
+   * @param keyPair
+   *          to sign with.
+   * @param username
+   *          sign username@mockmyid.com.
+   * @return encoded assertion string.
+   * @throws Exception
+   */
+  public String createMockMyIDAssertion(BrowserIDKeyPair keyPair, String username, String audience)
+      throws Exception {
+    long ciat = System.currentTimeMillis();
+    long cexp = ciat + JSONWebTokenUtils.DEFAULT_CERTIFICATE_DURATION_IN_MILLISECONDS;
+    long aiat = ciat + 1;
+    long aexp = aiat + JSONWebTokenUtils.DEFAULT_ASSERTION_DURATION_IN_MILLISECONDS;
+    return createMockMyIDAssertion(keyPair, username, audience,
+        ciat, cexp, aiat, aexp);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/RSACryptoImplementation.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/RSACryptoImplementation.java
new file mode 100644
index 000000000..902f6fb4d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/RSACryptoImplementation.java
@@ -0,0 +1,182 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid;
+
+import java.math.BigInteger;
+import java.security.GeneralSecurityException;
+import java.security.KeyFactory;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.NoSuchAlgorithmException;
+import java.security.Signature;
+import java.security.interfaces.RSAPrivateKey;
+import java.security.interfaces.RSAPublicKey;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.KeySpec;
+import java.security.spec.RSAPrivateKeySpec;
+import java.security.spec.RSAPublicKeySpec;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+
+public class RSACryptoImplementation {
+  public static final String SIGNATURE_ALGORITHM = "SHA256withRSA";
+
+  /**
+   * Parameters are serialized as decimal strings. Hex-versus-decimal was
+   * reverse-engineered from what the Persona public verifier accepted. We
+   * expect to follow the JOSE/JWT spec as it solidifies, and that will probably
+   * mean unifying this base.
+   */
+  protected static final int SERIALIZATION_BASE = 10;
+
+  protected static class RSAVerifyingPublicKey implements VerifyingPublicKey {
+    protected final RSAPublicKey publicKey;
+
+    public RSAVerifyingPublicKey(RSAPublicKey publicKey) {
+      this.publicKey = publicKey;
+    }
+
+    /**
+     * Serialize to a JSON object.
+     * <p>
+     * Parameters are serialized as decimal strings. Hex-versus-decimal was
+     * reverse-engineered from what the Persona public verifier accepted.
+     */
+    @Override
+    public ExtendedJSONObject toJSONObject() {
+      ExtendedJSONObject o = new ExtendedJSONObject();
+      o.put("algorithm", "RS");
+      o.put("n", publicKey.getModulus().toString(SERIALIZATION_BASE));
+      o.put("e", publicKey.getPublicExponent().toString(SERIALIZATION_BASE));
+      return o;
+    }
+
+    @Override
+    public boolean verifyMessage(byte[] bytes, byte[] signature)
+        throws GeneralSecurityException {
+      final Signature signer = Signature.getInstance(SIGNATURE_ALGORITHM);
+      signer.initVerify(publicKey);
+      signer.update(bytes);
+      return signer.verify(signature);
+    }
+  }
+
+  protected static class RSASigningPrivateKey implements SigningPrivateKey {
+    protected final RSAPrivateKey privateKey;
+
+    public RSASigningPrivateKey(RSAPrivateKey privateKey) {
+      this.privateKey = privateKey;
+    }
+
+    @Override
+    public String getAlgorithm() {
+      return "RS" + (privateKey.getModulus().bitLength() + 7)/8;
+    }
+
+    /**
+     * Serialize to a JSON object.
+     * <p>
+     * Parameters are serialized as decimal strings. Hex-versus-decimal was
+     * reverse-engineered from what the Persona public verifier accepted.
+     */
+    @Override
+    public ExtendedJSONObject toJSONObject() {
+      ExtendedJSONObject o = new ExtendedJSONObject();
+      o.put("algorithm", "RS");
+      o.put("n", privateKey.getModulus().toString(SERIALIZATION_BASE));
+      o.put("d", privateKey.getPrivateExponent().toString(SERIALIZATION_BASE));
+      return o;
+    }
+
+    @Override
+    public byte[] signMessage(byte[] bytes)
+        throws GeneralSecurityException {
+      final Signature signer = Signature.getInstance(SIGNATURE_ALGORITHM);
+      signer.initSign(privateKey);
+      signer.update(bytes);
+      return signer.sign();
+    }
+  }
+
+  public static BrowserIDKeyPair generateKeyPair(final int keysize) throws NoSuchAlgorithmException {
+    final KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
+    keyPairGenerator.initialize(keysize);
+    final KeyPair keyPair = keyPairGenerator.generateKeyPair();
+    RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
+    RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
+    return new BrowserIDKeyPair(new RSASigningPrivateKey(privateKey), new RSAVerifyingPublicKey(publicKey));
+  }
+
+  public static SigningPrivateKey createPrivateKey(BigInteger n, BigInteger d) throws NoSuchAlgorithmException, InvalidKeySpecException {
+    if (n == null) {
+      throw new IllegalArgumentException("n must not be null");
+    }
+    if (d == null) {
+      throw new IllegalArgumentException("d must not be null");
+    }
+    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
+    KeySpec keySpec = new RSAPrivateKeySpec(n, d);
+    RSAPrivateKey privateKey = (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
+    return new RSASigningPrivateKey(privateKey);
+  }
+
+  public static VerifyingPublicKey createPublicKey(BigInteger n, BigInteger e) throws NoSuchAlgorithmException, InvalidKeySpecException {
+    if (n == null) {
+      throw new IllegalArgumentException("n must not be null");
+    }
+    if (e == null) {
+      throw new IllegalArgumentException("e must not be null");
+    }
+    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
+    KeySpec keySpec = new RSAPublicKeySpec(n, e);
+    RSAPublicKey publicKey = (RSAPublicKey) keyFactory.generatePublic(keySpec);
+    return new RSAVerifyingPublicKey(publicKey);
+  }
+
+  public static SigningPrivateKey createPrivateKey(ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    String algorithm = o.getString("algorithm");
+    if (!"RS".equals(algorithm)) {
+      throw new InvalidKeySpecException("algorithm must equal RS, was " + algorithm);
+    }
+    try {
+      BigInteger n = new BigInteger(o.getString("n"), SERIALIZATION_BASE);
+      BigInteger d = new BigInteger(o.getString("d"), SERIALIZATION_BASE);
+      return createPrivateKey(n, d);
+    } catch (NullPointerException | NumberFormatException e) {
+      throw new InvalidKeySpecException("n and d must be integers encoded as strings, base " + SERIALIZATION_BASE);
+    }
+  }
+
+  public static VerifyingPublicKey createPublicKey(ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    String algorithm = o.getString("algorithm");
+    if (!"RS".equals(algorithm)) {
+      throw new InvalidKeySpecException("algorithm must equal RS, was " + algorithm);
+    }
+    try {
+      BigInteger n = new BigInteger(o.getString("n"), SERIALIZATION_BASE);
+      BigInteger e = new BigInteger(o.getString("e"), SERIALIZATION_BASE);
+      return createPublicKey(n, e);
+    } catch (NullPointerException | NumberFormatException e) {
+      throw new InvalidKeySpecException("n and e must be integers encoded as strings, base " + SERIALIZATION_BASE);
+    }
+  }
+
+  public static BrowserIDKeyPair fromJSONObject(ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    try {
+      ExtendedJSONObject privateKey = o.getObject(BrowserIDKeyPair.JSON_KEY_PRIVATEKEY);
+      ExtendedJSONObject publicKey = o.getObject(BrowserIDKeyPair.JSON_KEY_PUBLICKEY);
+      if (privateKey == null) {
+        throw new InvalidKeySpecException("privateKey must not be null");
+      }
+      if (publicKey == null) {
+        throw new InvalidKeySpecException("publicKey must not be null");
+      }
+      return new BrowserIDKeyPair(createPrivateKey(privateKey), createPublicKey(publicKey));
+    } catch (NonObjectJSONException e) {
+      throw new InvalidKeySpecException("privateKey and publicKey must be JSON objects");
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/SigningPrivateKey.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/SigningPrivateKey.java
new file mode 100644
index 000000000..6c388d167
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/SigningPrivateKey.java
@@ -0,0 +1,41 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid;
+
+import java.security.GeneralSecurityException;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+public interface SigningPrivateKey {
+  /**
+   * Return the JSON Web Token "alg" header corresponding to this private key.
+   * <p>
+   * The header is used when formatting web tokens, and generally denotes the
+   * algorithm and an ad-hoc encoding of the key size.
+   *
+   * @return header.
+   */
+  public String getAlgorithm();
+
+  /**
+   * Generate a JSON representation of a private key.
+   * <p>
+   * <b>This should only be used for debugging. No private keys should go over
+   * the wire at any time.</b>
+   *
+   * @param privateKey
+   *          to represent.
+   * @return JSON representation.
+   */
+  public ExtendedJSONObject toJSONObject();
+
+  /**
+   * Sign a message.
+   * @param message to sign.
+   * @return signature.
+   * @throws GeneralSecurityException
+   */
+  public byte[] signMessage(byte[] message) throws GeneralSecurityException;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/VerifyingPublicKey.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/VerifyingPublicKey.java
new file mode 100644
index 000000000..74b534b90
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/VerifyingPublicKey.java
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid;
+
+import java.security.GeneralSecurityException;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+
+public interface VerifyingPublicKey {
+  /**
+   * Generate a JSON representation of a public key.
+   *
+   * @param publicKey
+   *          to represent.
+   * @return JSON representation.
+   */
+  public ExtendedJSONObject toJSONObject();
+
+  /**
+   * Verify a signature.
+   *
+   * @param message
+   *          to verify signature of.
+   * @param signature
+   *          to verify.
+   * @return true if signature is a signature of message produced by the private
+   *         key corresponding to this public key.
+   * @throws GeneralSecurityException
+   */
+  public boolean verifyMessage(byte[] message, byte[] signature) throws GeneralSecurityException;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/AbstractBrowserIDRemoteVerifierClient.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/AbstractBrowserIDRemoteVerifierClient.java
new file mode 100644
index 000000000..aa8db2d48
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/AbstractBrowserIDRemoteVerifierClient.java
@@ -0,0 +1,95 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid.verifier;
+
+import java.io.IOException;
+import java.net.URI;
+import java.security.GeneralSecurityException;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.browserid.verifier.BrowserIDVerifierException.BrowserIDVerifierErrorResponseException;
+import org.mozilla.gecko.browserid.verifier.BrowserIDVerifierException.BrowserIDVerifierMalformedResponseException;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.net.BaseResourceDelegate;
+import org.mozilla.gecko.sync.net.Resource;
+import org.mozilla.gecko.sync.net.SyncResponse;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.ClientProtocolException;
+
+public abstract class AbstractBrowserIDRemoteVerifierClient implements BrowserIDVerifierClient {
+  public static final String LOG_TAG = AbstractBrowserIDRemoteVerifierClient.class.getSimpleName();
+
+  protected static class RemoteVerifierResourceDelegate extends BaseResourceDelegate {
+    private final BrowserIDVerifierDelegate delegate;
+
+    protected RemoteVerifierResourceDelegate(Resource resource, BrowserIDVerifierDelegate delegate) {
+      super(resource);
+      this.delegate = delegate;
+    }
+
+    @Override
+    public String getUserAgent() {
+      return null;
+    }
+
+    @Override
+    public void handleHttpResponse(HttpResponse response) {
+      SyncResponse res = new SyncResponse(response);
+      int statusCode = res.getStatusCode();
+      Logger.debug(LOG_TAG, "Got response with status code " + statusCode + ".");
+
+      if (statusCode != 200) {
+        delegate.handleError(new BrowserIDVerifierErrorResponseException("Expected status code 200."));
+        return;
+      }
+
+      ExtendedJSONObject o = null;
+      try {
+        o = res.jsonObjectBody();
+      } catch (Exception e) {
+        delegate.handleError(new BrowserIDVerifierMalformedResponseException(e));
+        return;
+      }
+
+      String status = o.getString("status");
+      if ("failure".equals(status)) {
+        delegate.handleFailure(o);
+        return;
+      }
+
+      if (!("okay".equals(status))) {
+        delegate.handleError(new BrowserIDVerifierMalformedResponseException("Expected status okay, got '" + status + "'."));
+        return;
+      }
+
+      delegate.handleSuccess(o);
+    }
+
+    @Override
+    public void handleTransportException(GeneralSecurityException e) {
+      Logger.warn(LOG_TAG, "Got transport exception.", e);
+      delegate.handleError(e);
+    }
+
+    @Override
+    public void handleHttpProtocolException(ClientProtocolException e) {
+      Logger.warn(LOG_TAG, "Got protocol exception.", e);
+      delegate.handleError(e);
+    }
+
+    @Override
+    public void handleHttpIOException(IOException e) {
+      Logger.warn(LOG_TAG, "Got IO exception.", e);
+      delegate.handleError(e);
+    }
+  }
+
+  protected final URI verifierUri;
+
+  public AbstractBrowserIDRemoteVerifierClient(URI verifierUri) {
+    this.verifierUri = verifierUri;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDRemoteVerifierClient10.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDRemoteVerifierClient10.java
new file mode 100644
index 000000000..f61a82323
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDRemoteVerifierClient10.java
@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid.verifier;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.Arrays;
+import java.util.List;
+
+import org.mozilla.gecko.sync.net.BaseResource;
+
+import ch.boye.httpclientandroidlib.NameValuePair;
+import ch.boye.httpclientandroidlib.client.entity.UrlEncodedFormEntity;
+import ch.boye.httpclientandroidlib.message.BasicNameValuePair;
+
+/**
+ * The verifier protocol changed: version 1 posts form-encoded data; version 2
+ * posts JSON data.
+ */
+public class BrowserIDRemoteVerifierClient10 extends AbstractBrowserIDRemoteVerifierClient {
+  public static final String LOG_TAG = BrowserIDRemoteVerifierClient10.class.getSimpleName();
+
+  public static final String DEFAULT_VERIFIER_URL = "https://verifier.login.persona.org/verify";
+
+  public BrowserIDRemoteVerifierClient10() throws URISyntaxException {
+    super(new URI(DEFAULT_VERIFIER_URL));
+  }
+
+  public BrowserIDRemoteVerifierClient10(URI verifierUri) {
+    super(verifierUri);
+  }
+
+  @Override
+  public void verify(String audience, String assertion, final BrowserIDVerifierDelegate delegate) {
+    if (audience == null) {
+      throw new IllegalArgumentException("audience cannot be null.");
+    }
+    if (assertion == null) {
+      throw new IllegalArgumentException("assertion cannot be null.");
+    }
+    if (delegate == null) {
+      throw new IllegalArgumentException("delegate cannot be null.");
+    }
+
+    BaseResource r = new BaseResource(verifierUri);
+
+    r.delegate = new RemoteVerifierResourceDelegate(r, delegate);
+
+    List<NameValuePair> nvps = Arrays.asList(new NameValuePair[] {
+        new BasicNameValuePair("audience", audience),
+        new BasicNameValuePair("assertion", assertion) });
+
+    try {
+      r.post(new UrlEncodedFormEntity(nvps, "UTF-8"));
+    } catch (UnsupportedEncodingException e) {
+      delegate.handleError(e);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDRemoteVerifierClient20.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDRemoteVerifierClient20.java
new file mode 100644
index 000000000..013856576
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDRemoteVerifierClient20.java
@@ -0,0 +1,58 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid.verifier;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.net.BaseResource;
+
+/**
+ * The verifier protocol changed: version 1 posts form-encoded data; version 2
+ * posts JSON data.
+ */
+public class BrowserIDRemoteVerifierClient20 extends AbstractBrowserIDRemoteVerifierClient {
+  public static final String LOG_TAG = BrowserIDRemoteVerifierClient20.class.getSimpleName();
+
+  public static final String DEFAULT_VERIFIER_URL = "https://verifier.accounts.firefox.com/v2";
+
+  protected static final String JSON_KEY_ASSERTION = "assertion";
+  protected static final String JSON_KEY_AUDIENCE = "audience";
+
+  public BrowserIDRemoteVerifierClient20() throws URISyntaxException {
+    super(new URI(DEFAULT_VERIFIER_URL));
+  }
+
+  public BrowserIDRemoteVerifierClient20(URI verifierUri) {
+    super(verifierUri);
+  }
+
+  @Override
+  public void verify(String audience, String assertion, final BrowserIDVerifierDelegate delegate) {
+    if (audience == null) {
+      throw new IllegalArgumentException("audience cannot be null.");
+    }
+    if (assertion == null) {
+      throw new IllegalArgumentException("assertion cannot be null.");
+    }
+    if (delegate == null) {
+      throw new IllegalArgumentException("delegate cannot be null.");
+    }
+
+    BaseResource r = new BaseResource(verifierUri);
+    r.delegate = new RemoteVerifierResourceDelegate(r, delegate);
+
+    final ExtendedJSONObject requestBody = new ExtendedJSONObject();
+    requestBody.put(JSON_KEY_AUDIENCE, audience);
+    requestBody.put(JSON_KEY_ASSERTION, assertion);
+
+    try {
+      r.post(requestBody);
+    } catch (Exception e) {
+      delegate.handleError(e);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDVerifierClient.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDVerifierClient.java
new file mode 100644
index 000000000..67a327f19
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDVerifierClient.java
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid.verifier;
+
+public interface BrowserIDVerifierClient {
+  public abstract void verify(String audience, String assertion, BrowserIDVerifierDelegate delegate);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDVerifierDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDVerifierDelegate.java
new file mode 100644
index 000000000..b58d03281
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDVerifierDelegate.java
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid.verifier;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+public interface BrowserIDVerifierDelegate {
+  void handleSuccess(ExtendedJSONObject response);
+  void handleFailure(ExtendedJSONObject response);
+  void handleError(Exception e);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDVerifierException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDVerifierException.java
new file mode 100644
index 000000000..dacaf6112
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/verifier/BrowserIDVerifierException.java
@@ -0,0 +1,41 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.browserid.verifier;
+
+public class BrowserIDVerifierException extends Exception {
+  private static final long serialVersionUID = 2228946910754889975L;
+
+  public BrowserIDVerifierException(String detailMessage) {
+    super(detailMessage);
+  }
+
+  public BrowserIDVerifierException(Throwable throwable) {
+    super(throwable);
+  }
+
+  public static class BrowserIDVerifierMalformedResponseException extends BrowserIDVerifierException {
+    private static final long serialVersionUID = 115377527009652839L;
+
+    public BrowserIDVerifierMalformedResponseException(String detailMessage) {
+      super(detailMessage);
+    }
+
+    public BrowserIDVerifierMalformedResponseException(Throwable throwable) {
+      super(throwable);
+    }
+  }
+
+  public static class BrowserIDVerifierErrorResponseException extends BrowserIDVerifierException {
+    private static final long serialVersionUID = 115377527009652840L;
+
+    public BrowserIDVerifierErrorResponseException(String detailMessage) {
+      super(detailMessage);
+    }
+
+    public BrowserIDVerifierErrorResponseException(Throwable throwable) {
+      super(throwable);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/AccountLoader.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/AccountLoader.java
new file mode 100644
index 000000000..8a31c1ce0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/AccountLoader.java
@@ -0,0 +1,227 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa;
+
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.Handler;
+import android.os.Looper;
+import android.content.AsyncTaskLoader;
+import android.support.v4.content.LocalBroadcastManager;
+
+import java.lang.ref.WeakReference;
+
+/**
+ * A Loader that queries and updates based on the existence of Firefox and
+ * legacy Sync Android Accounts.
+ *
+ * The loader returns an Android Account (of either Account type) if an account
+ * exists, and null to indicate no Account is present.
+ *
+ * The loader listens for Accounts added and deleted, and also Accounts being
+ * updated by Sync or another Activity, via the use of
+ * {@link AndroidFxAccount#setState(org.mozilla.gecko.fxa.login.State)}.
+ * Be careful of message loops if you update the account state from an activity
+ * that uses this loader.
+ *
+ * This implementation is based on
+ * <a href="http://www.androiddesignpatterns.com/2012/08/implementing-loaders.html">http://www.androiddesignpatterns.com/2012/08/implementing-loaders.html</a>.
+ */
+public class AccountLoader extends AsyncTaskLoader<Account> {
+  protected Account account = null;
+  protected BroadcastReceiver broadcastReceiver = null;
+
+  // Hold a weak reference to AccountLoader instance in this Runnable to avoid potentially leaking it
+  // after posting to a Handler in the BroadcastReceiver returned from makeNewObserver.
+  private final BroadcastReceiverRunnable broadcastReceiverRunnable = new BroadcastReceiverRunnable(this);
+
+  public AccountLoader(final Context context) {
+    super(context);
+  }
+
+  // Task that performs the asynchronous load.
+  @Override
+  public Account loadInBackground() {
+    return FirefoxAccounts.getFirefoxAccount(getContext());
+  }
+
+  // Deliver the results to the registered listener.
+  @Override
+  public void deliverResult(Account data) {
+    if (isReset()) {
+      // The Loader has been reset; ignore the result and invalidate the data.
+      releaseResources(data);
+      return;
+    }
+
+    // Hold a reference to the old data so it doesn't get garbage collected.
+    // We must protect it until the new data has been delivered.
+    Account oldData = account;
+    account = data;
+
+    if (isStarted()) {
+      // If the Loader is in a started state, deliver the results to the
+      // client. The superclass method does this for us.
+      super.deliverResult(data);
+    }
+
+    // Invalidate the old data as we don't need it any more.
+    if (oldData != null && oldData != data) {
+      releaseResources(oldData);
+    }
+  }
+
+  // The Loader’s state-dependent behavior.
+  @Override
+  protected void onStartLoading() {
+    if (account != null) {
+      // Deliver any previously loaded data immediately.
+      deliverResult(account);
+    }
+
+    // Begin monitoring the underlying data source.
+    if (broadcastReceiver == null) {
+      broadcastReceiver = makeNewObserver();
+      registerLocalObserver(getContext(), broadcastReceiver);
+      registerSystemObserver(getContext(), broadcastReceiver);
+    }
+
+    if (takeContentChanged() || account == null) {
+      // When the observer detects a change, it should call onContentChanged()
+      // on the Loader, which will cause the next call to takeContentChanged()
+      // to return true. If this is ever the case (or if the current data is
+      // null), we force a new load.
+      forceLoad();
+    }
+  }
+
+  @Override
+  protected void onStopLoading() {
+    // The Loader is in a stopped state, so we should attempt to cancel the
+    // current load (if there is one).
+    cancelLoad();
+
+    // Note that we leave the observer as is. Loaders in a stopped state
+    // should still monitor the data source for changes so that the Loader
+    // will know to force a new load if it is ever started again.
+  }
+
+  @Override
+  protected void onReset() {
+    // Ensure the loader has been stopped.  In CursorLoader and the template
+    // this code follows (see the class comment), this is onStopLoading, which
+    // appears to not set the started flag (see Loader itself).
+    stopLoading();
+
+    // At this point we can release the resources associated with 'mData'.
+    if (account != null) {
+      releaseResources(account);
+      account = null;
+    }
+
+    // The Loader is being reset, so we should stop monitoring for changes.
+    if (broadcastReceiver != null) {
+      final BroadcastReceiver observer = broadcastReceiver;
+      broadcastReceiver = null;
+      unregisterObserver(getContext(), observer);
+    }
+  }
+
+  @Override
+  public void onCanceled(final Account data) {
+    // Attempt to cancel the current asynchronous load.
+    super.onCanceled(data);
+
+    // The load has been canceled, so we should release the resources
+    // associated with 'data'.
+    releaseResources(data);
+  }
+
+  // Observer which receives notifications when the data changes.
+  protected BroadcastReceiver makeNewObserver() {
+    return new BroadcastReceiver() {
+      @Override
+      public void onReceive(Context context, Intent intent) {
+        // onContentChanged must be called on the main thread.
+        // If we're already on the main thread, call it directly.
+        if (Looper.myLooper() == Looper.getMainLooper()) {
+          onContentChanged();
+          return;
+        }
+
+        // Otherwise, post a Runnable to a Handler bound to the main thread's message loop.
+        final Handler mainHandler = new Handler(Looper.getMainLooper());
+        mainHandler.post(broadcastReceiverRunnable);
+      }
+    };
+  }
+
+  private static class BroadcastReceiverRunnable implements Runnable {
+    private final WeakReference<AccountLoader> accountLoaderWeakReference;
+
+    public BroadcastReceiverRunnable(final AccountLoader accountLoader) {
+      accountLoaderWeakReference = new WeakReference<>(accountLoader);
+    }
+
+    @Override
+    public void run() {
+      final AccountLoader accountLoader = accountLoaderWeakReference.get();
+      if (accountLoader != null) {
+        accountLoader.onContentChanged();
+      }
+    }
+  }
+
+  private void releaseResources(Account data) {
+    // For a simple List, there is nothing to do. For something like a Cursor, we
+    // would close it in this method. All resources associated with the Loader
+    // should be released here.
+  }
+
+  /**
+   * Register provided observer with the LocalBroadcastManager to listen for internal events.
+   *
+   * @param context <code>Context</code> to use for obtaining LocalBroadcastManager instance.
+   * @param observer <code>BroadcastReceiver</code> which will handle local events.
+   */
+  protected static void registerLocalObserver(final Context context, final BroadcastReceiver observer) {
+    final IntentFilter intentFilter = new IntentFilter();
+    // Firefox Account internal state changed.
+    intentFilter.addAction(FxAccountConstants.ACCOUNT_STATE_CHANGED_ACTION);
+    // Firefox Account profile state changed.
+    intentFilter.addAction(FxAccountConstants.ACCOUNT_PROFILE_JSON_UPDATED_ACTION);
+
+    LocalBroadcastManager.getInstance(context).registerReceiver(observer, intentFilter);
+  }
+
+  /**
+   * Register provided observer for handling system-wide broadcasts.
+   *
+   * @param context <code>Context</code> to use for registering a receiver.
+   * @param observer <code>BroadcastReceiver</code> which will handle system events.
+   */
+  protected static void registerSystemObserver(final Context context, final BroadcastReceiver observer) {
+    context.registerReceiver(observer,
+            // Android Account added or removed.
+            new IntentFilter(AccountManager.LOGIN_ACCOUNTS_CHANGED_ACTION),
+            // No broadcast permissions required.
+            null,
+            // Null handler ensures that broadcasts will be handled on the main thread.
+            null
+    );
+  }
+
+  protected static void unregisterObserver(final Context context, final BroadcastReceiver observer) {
+    LocalBroadcastManager.getInstance(context).unregisterReceiver(observer);
+    context.unregisterReceiver(observer);
+  }
+}
+
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FirefoxAccounts.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FirefoxAccounts.java
new file mode 100644
index 000000000..4184340ec
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FirefoxAccounts.java
@@ -0,0 +1,222 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa;
+
+import java.io.File;
+import java.util.concurrent.CountDownLatch;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.fxa.authenticator.AccountPickler;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.fxa.sync.FxAccountSyncStatusHelper;
+import org.mozilla.gecko.sync.ThreadPool;
+import org.mozilla.gecko.sync.Utils;
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.os.Bundle;
+
+/**
+ * Simple public accessors for Firefox account objects.
+ */
+public class FirefoxAccounts {
+  private static final String LOG_TAG = FirefoxAccounts.class.getSimpleName();
+
+  /**
+   * Returns true if a FirefoxAccount exists, false otherwise.
+   *
+   * @param context Android context.
+   * @return true if at least one Firefox account exists.
+   */
+  public static boolean firefoxAccountsExist(final Context context) {
+    return getFirefoxAccounts(context).length > 0;
+  }
+
+  /**
+   * Return Firefox accounts.
+   * <p>
+   * If no accounts exist in the AccountManager, one may be created
+   * via a pickled FirefoxAccount, if available, and that account
+   * will be added to the AccountManager and returned.
+   * <p>
+   * Note that this can be called from any thread.
+   *
+   * @param context Android context.
+   * @return Firefox account objects.
+   */
+  public static Account[] getFirefoxAccounts(final Context context) {
+    final Account[] accounts =
+        AccountManager.get(context).getAccountsByType(FxAccountConstants.ACCOUNT_TYPE);
+    if (accounts.length > 0) {
+      return accounts;
+    }
+
+    final Account pickledAccount = getPickledAccount(context);
+    return (pickledAccount != null) ? new Account[] {pickledAccount} : new Account[0];
+  }
+
+  private static Account getPickledAccount(final Context context) {
+    // To avoid a StrictMode violation for disk access, we call this from a background thread.
+    // We do this every time, so the caller doesn't have to care.
+    final CountDownLatch latch = new CountDownLatch(1);
+    final Account[] accounts = new Account[1];
+    ThreadPool.run(new Runnable() {
+      @Override
+      public void run() {
+        try {
+          final File file = context.getFileStreamPath(FxAccountConstants.ACCOUNT_PICKLE_FILENAME);
+          if (!file.exists()) {
+            accounts[0] = null;
+            return;
+          }
+
+          // There is a small race window here: if the user creates a new Firefox account
+          // between our checks, this could erroneously report that no Firefox accounts
+          // exist.
+          final AndroidFxAccount fxAccount =
+              AccountPickler.unpickle(context, FxAccountConstants.ACCOUNT_PICKLE_FILENAME);
+          accounts[0] = fxAccount != null ? fxAccount.getAndroidAccount() : null;
+        } finally {
+          latch.countDown();
+        }
+      }
+    });
+
+    try {
+      latch.await(); // Wait for the background thread to return.
+    } catch (InterruptedException e) {
+      Logger.warn(LOG_TAG,
+          "Foreground thread unexpectedly interrupted while getting pickled account", e);
+      return null;
+    }
+
+    return accounts[0];
+  }
+
+  /**
+   * @param context Android context.
+   * @return the configured Firefox account if one exists, or null otherwise.
+   */
+  public static Account getFirefoxAccount(final Context context) {
+    Account[] accounts = getFirefoxAccounts(context);
+    if (accounts.length > 0) {
+      return accounts[0];
+    }
+    return null;
+  }
+
+  /**
+   * @return
+   *     the {@link State} instance associated with the current account, or <code>null</code> if
+   *     no accounts exist.
+   */
+  public static State getFirefoxAccountState(final Context context) {
+    final Account account = getFirefoxAccount(context);
+    if (account == null) {
+      return null;
+    }
+
+    final AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+    try {
+      return fxAccount.getState();
+    } catch (final Exception ex) {
+      Logger.warn(LOG_TAG, "Could not get FX account state.", ex);
+      return null;
+    }
+  }
+
+  /*
+   * @param context Android context
+   * @return the email address associated with the configured Firefox account if one exists; null otherwise.
+   */
+  public static String getFirefoxAccountEmail(final Context context) {
+    final Account account = getFirefoxAccount(context);
+    if (account == null) {
+      return null;
+    }
+    return account.name;
+  }
+
+  public static void logSyncOptions(Bundle syncOptions) {
+    final boolean scheduleNow = syncOptions.getBoolean(ContentResolver.SYNC_EXTRAS_IGNORE_BACKOFF, false);
+
+    Logger.info(LOG_TAG, "Sync options -- scheduling now: " + scheduleNow);
+  }
+
+  public static void requestImmediateSync(final Account account, String[] stagesToSync, String[] stagesToSkip) {
+    final Bundle syncOptions = new Bundle();
+    syncOptions.putBoolean(ContentResolver.SYNC_EXTRAS_IGNORE_BACKOFF, true);
+    syncOptions.putBoolean(ContentResolver.SYNC_EXTRAS_EXPEDITED, true);
+    requestSync(account, syncOptions, stagesToSync, stagesToSkip);
+  }
+
+  public static void requestEventualSync(final Account account, String[] stagesToSync, String[] stagesToSkip) {
+    requestSync(account, Bundle.EMPTY, stagesToSync, stagesToSkip);
+  }
+
+  /**
+   * Request a sync for the given Android Account.
+   * <p>
+   * Any hints are strictly optional: the actual requested sync is scheduled by
+   * the Android sync scheduler, and the sync mechanism may ignore hints as it
+   * sees fit.
+   * <p>
+   * It is safe to call this method from any thread.
+   *
+   * @param account to sync.
+   * @param syncOptions to pass to sync.
+   * @param stagesToSync stage names to sync.
+   * @param stagesToSkip stage names to skip.
+   */
+  protected static void requestSync(final Account account, final Bundle syncOptions, String[] stagesToSync, String[] stagesToSkip) {
+    if (account == null) {
+      throw new IllegalArgumentException("account must not be null");
+    }
+    if (syncOptions == null) {
+      throw new IllegalArgumentException("syncOptions must not be null");
+    }
+
+    Utils.putStageNamesToSync(syncOptions, stagesToSync, stagesToSkip);
+
+    Logger.info(LOG_TAG, "Requesting sync.");
+    logSyncOptions(syncOptions);
+
+    // We get strict mode warnings on some devices, so make the request on a
+    // background thread.
+    ThreadPool.run(new Runnable() {
+      @Override
+      public void run() {
+        for (String authority : AndroidFxAccount.DEFAULT_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP.keySet()) {
+          ContentResolver.requestSync(account, authority, syncOptions);
+        }
+      }
+    });
+  }
+
+  /**
+   * Start notifying <code>syncStatusListener</code> of sync status changes.
+   * <p>
+   * Only a weak reference to <code>syncStatusListener</code> is held.
+   *
+   * @param syncStatusListener to start notifying.
+   */
+  public static void addSyncStatusListener(SyncStatusListener syncStatusListener) {
+    // startObserving null-checks its argument.
+    FxAccountSyncStatusHelper.getInstance().startObserving(syncStatusListener);
+  }
+
+  /**
+   * Stop notifying <code>syncStatusListener</code> of sync status changes.
+   *
+   * @param syncStatusListener to stop notifying.
+   */
+  public static void removeSyncStatusListener(SyncStatusListener syncStatusListener) {
+    // stopObserving null-checks its argument.
+    FxAccountSyncStatusHelper.getInstance().stopObserving(syncStatusListener);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountConstants.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountConstants.java
new file mode 100644
index 000000000..c6147b323
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountConstants.java
@@ -0,0 +1,75 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa;
+
+import org.mozilla.gecko.AppConstants;
+
+public class FxAccountConstants {
+  public static final String GLOBAL_LOG_TAG = "FxAccounts";
+  public static final String ACCOUNT_TYPE = AppConstants.MOZ_ANDROID_SHARED_FXACCOUNT_TYPE;
+
+  // Must be a client ID allocated with "canGrant" privileges!
+  public static final String OAUTH_CLIENT_ID_FENNEC = "3332a18d142636cb";
+
+  public static final String DEFAULT_AUTH_SERVER_ENDPOINT = "https://api.accounts.firefox.com/v1";
+  public static final String DEFAULT_TOKEN_SERVER_ENDPOINT = "https://token.services.mozilla.com/1.0/sync/1.5";
+  public static final String DEFAULT_OAUTH_SERVER_ENDPOINT = "https://oauth.accounts.firefox.com/v1";
+  public static final String DEFAULT_PROFILE_SERVER_ENDPOINT = "https://profile.accounts.firefox.com/v1";
+
+  public static final String STAGE_AUTH_SERVER_ENDPOINT = "https://stable.dev.lcip.org/auth/v1";
+  public static final String STAGE_TOKEN_SERVER_ENDPOINT = "https://stable.dev.lcip.org/syncserver/token/1.0/sync/1.5";
+  public static final String STAGE_OAUTH_SERVER_ENDPOINT = "https://oauth-stable.dev.lcip.org/v1";
+  public static final String STAGE_PROFILE_SERVER_ENDPOINT = "https://latest.dev.lcip.org/profile/v1";
+
+  // Action to update on cached profile information.
+  public static final String ACCOUNT_PROFILE_JSON_UPDATED_ACTION = "org.mozilla.gecko.fxa.profile.JSON.updated";
+
+  // You must be at least 13 years old, on the day of creation, to create a Firefox Account.
+  public static final int MINIMUM_AGE_TO_CREATE_AN_ACCOUNT = 13;
+
+  // Key for avatar URI in profile JSON.
+  public static final String KEY_PROFILE_JSON_AVATAR = "avatar";
+  // Key for username in profile JSON.
+  public static final String KEY_PROFILE_JSON_USERNAME = "displayName";
+
+  // You must wait 15 minutes after failing an age check before trying to create a different account.
+  public static final long MINIMUM_TIME_TO_WAIT_AFTER_AGE_CHECK_FAILED_IN_MILLISECONDS = 15 * 60 * 1000;
+
+  public static final String USER_AGENT = "Firefox-Android-FxAccounts/" + AppConstants.MOZ_APP_VERSION + " (" + AppConstants.MOZ_APP_UA_NAME + ")";
+
+  public static final String ACCOUNT_PICKLE_FILENAME = "fxa.account.json";
+
+
+  /**
+   * Version number of contents of SYNC_ACCOUNT_DELETED_ACTION intent.
+   */
+  public static final long ACCOUNT_DELETED_INTENT_VERSION = 1;
+
+  public static final String ACCOUNT_DELETED_INTENT_VERSION_KEY = "account_deleted_intent_version";
+  public static final String ACCOUNT_DELETED_INTENT_ACCOUNT_KEY = "account_deleted_intent_account";
+  public static final String ACCOUNT_DELETED_INTENT_ACCOUNT_PROFILE = "account_deleted_intent_profile";
+  public static final String ACCOUNT_OAUTH_SERVICE_ENDPOINT_KEY = "account_oauth_service_endpoint";
+  public static final String ACCOUNT_DELETED_INTENT_ACCOUNT_AUTH_TOKENS = "account_deleted_intent_auth_tokens";
+
+  /**
+   * This action is broadcast when an Android Firefox Account's internal state
+   * is changed.
+   * <p>
+   * It is protected by signing-level permission PER_ACCOUNT_TYPE_PERMISSION and
+   * can be received only by Firefox versions sharing the same Android Firefox
+   * Account type.
+   */
+  public static final String ACCOUNT_STATE_CHANGED_ACTION = AppConstants.MOZ_ANDROID_SHARED_FXACCOUNT_TYPE + ".accounts.ACCOUNT_STATE_CHANGED_ACTION";
+
+  public static final String ACTION_FXA_CONFIRM_ACCOUNT            = AppConstants.ANDROID_PACKAGE_NAME + ".ACTION_FXA_CONFIRM_ACCOUNT";
+  public static final String ACTION_FXA_FINISH_MIGRATING           = AppConstants.ANDROID_PACKAGE_NAME + ".ACTION_FXA_FINISH_MIGRATING";
+  public static final String ACTION_FXA_GET_STARTED                = AppConstants.ANDROID_PACKAGE_NAME + ".ACTION_FXA_GET_STARTED";
+  public static final String ACTION_FXA_STATUS                     = AppConstants.ANDROID_PACKAGE_NAME + ".ACTION_FXA_STATUS";
+  public static final String ACTION_FXA_UPDATE_CREDENTIALS         = AppConstants.ANDROID_PACKAGE_NAME + ".ACTION_FXA_UPDATE_CREDENTIALS";
+
+  public static final String ENDPOINT_PREFERENCES  = "preferences";
+  public static final String ENDPOINT_NOTIFICATION = "notification";
+  public static final String ENDPOINT_FIRSTRUN = "firstrun";
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountDevice.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountDevice.java
new file mode 100644
index 000000000..cd46ae2bd
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountDevice.java
@@ -0,0 +1,81 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+public class FxAccountDevice {
+
+  public static final String JSON_KEY_NAME = "name";
+  public static final String JSON_KEY_ID = "id";
+  public static final String JSON_KEY_TYPE = "type";
+  public static final String JSON_KEY_ISCURRENTDEVICE = "isCurrentDevice";
+  public static final String JSON_KEY_PUSH_CALLBACK = "pushCallback";
+  public static final String JSON_KEY_PUSH_PUBLICKEY = "pushPublicKey";
+  public static final String JSON_KEY_PUSH_AUTHKEY = "pushAuthKey";
+
+  public final String id;
+  public final String name;
+  public final String type;
+  public final Boolean isCurrentDevice;
+  public final String pushCallback;
+  public final String pushPublicKey;
+  public final String pushAuthKey;
+
+  public FxAccountDevice(String name, String id, String type, Boolean isCurrentDevice,
+                         String pushCallback, String pushPublicKey, String pushAuthKey) {
+    this.name = name;
+    this.id = id;
+    this.type = type;
+    this.isCurrentDevice = isCurrentDevice;
+    this.pushCallback = pushCallback;
+    this.pushPublicKey = pushPublicKey;
+    this.pushAuthKey = pushAuthKey;
+  }
+
+  public static FxAccountDevice forRegister(String name, String type, String pushCallback,
+                                            String pushPublicKey, String pushAuthKey) {
+    return new FxAccountDevice(name, null, type, null, pushCallback, pushPublicKey, pushAuthKey);
+  }
+
+  public static FxAccountDevice forUpdate(String id, String name, String pushCallback,
+                                          String pushPublicKey, String pushAuthKey) {
+    return new FxAccountDevice(name, id, null, null, pushCallback, pushPublicKey, pushAuthKey);
+  }
+
+  public static FxAccountDevice fromJson(ExtendedJSONObject json) {
+    String name = json.getString(JSON_KEY_NAME);
+    String id = json.getString(JSON_KEY_ID);
+    String type = json.getString(JSON_KEY_TYPE);
+    Boolean isCurrentDevice = json.getBoolean(JSON_KEY_ISCURRENTDEVICE);
+    String pushCallback = json.getString(JSON_KEY_PUSH_CALLBACK);
+    String pushPublicKey = json.getString(JSON_KEY_PUSH_PUBLICKEY);
+    String pushAuthKey = json.getString(JSON_KEY_PUSH_AUTHKEY);
+    return new FxAccountDevice(name, id, type, isCurrentDevice, pushCallback, pushPublicKey, pushAuthKey);
+  }
+
+  public ExtendedJSONObject toJson() {
+    final ExtendedJSONObject body = new ExtendedJSONObject();
+    if (this.name != null) {
+      body.put(JSON_KEY_NAME, this.name);
+    }
+    if (this.id != null) {
+      body.put(JSON_KEY_ID, this.id);
+    }
+    if (this.type != null) {
+      body.put(JSON_KEY_TYPE, this.type);
+    }
+    if (this.pushCallback != null) {
+      body.put(JSON_KEY_PUSH_CALLBACK, this.pushCallback);
+    }
+    if (this.pushPublicKey != null) {
+      body.put(JSON_KEY_PUSH_PUBLICKEY, this.pushPublicKey);
+    }
+    if (this.pushAuthKey != null) {
+      body.put(JSON_KEY_PUSH_AUTHKEY, this.pushAuthKey);
+    }
+    return body;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountDeviceRegistrator.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountDeviceRegistrator.java
new file mode 100644
index 000000000..66a8ad843
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountDeviceRegistrator.java
@@ -0,0 +1,282 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa;
+
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.text.TextUtils;
+import android.util.Log;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountClient;
+import org.mozilla.gecko.background.fxa.FxAccountClient20;
+import org.mozilla.gecko.background.fxa.FxAccountClient20.AccountStatusResponse;
+import org.mozilla.gecko.background.fxa.FxAccountClient20.RequestDelegate;
+import org.mozilla.gecko.background.fxa.FxAccountClientException.FxAccountClientRemoteException;
+import org.mozilla.gecko.background.fxa.FxAccountRemoteError;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount.InvalidFxAState;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.sync.SharedPreferencesClientsDataDelegate;
+import org.mozilla.gecko.util.BundleEventListener;
+import org.mozilla.gecko.util.EventCallback;
+
+import java.io.UnsupportedEncodingException;
+import java.lang.ref.WeakReference;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.security.GeneralSecurityException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/* This class provides a way to register the current device against FxA
+ * and also stores the registration details in the Android FxAccount.
+ * This should be used in a state where we possess a sessionToken, most likely the Married state.
+ */
+public class FxAccountDeviceRegistrator implements BundleEventListener {
+  private static final String LOG_TAG = "FxADeviceRegistrator";
+
+  // The current version of the device registration, we use this to re-register
+  // devices after we update what we send on device registration.
+  public static final Integer DEVICE_REGISTRATION_VERSION = 2;
+
+  private static FxAccountDeviceRegistrator instance;
+  private final WeakReference<Context> context;
+
+  private FxAccountDeviceRegistrator(Context appContext) {
+    this.context = new WeakReference<Context>(appContext);
+  }
+
+  private static FxAccountDeviceRegistrator getInstance(Context appContext) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
+    if (instance == null) {
+      FxAccountDeviceRegistrator tempInstance = new FxAccountDeviceRegistrator(appContext);
+      tempInstance.setupListeners(); // Set up listener for FxAccountPush:Subscribe:Response
+      instance = tempInstance;
+    }
+    return instance;
+  }
+
+  public static void register(Context context) {
+    Context appContext = context.getApplicationContext();
+    try {
+      getInstance(appContext).beginRegistration(appContext);
+    } catch (Exception e) {
+      Log.e(LOG_TAG, "Could not start FxA device registration", e);
+    }
+  }
+
+  private void beginRegistration(Context context) {
+    // Fire up gecko and send event
+    // We create the Intent ourselves instead of using GeckoService.getIntentToCreateServices
+    // because we can't import these modules (circular dependency between browser and services)
+    final Intent geckoIntent = new Intent();
+    geckoIntent.setAction("create-services");
+    geckoIntent.setClassName(context, "org.mozilla.gecko.GeckoService");
+    geckoIntent.putExtra("category", "android-push-service");
+    geckoIntent.putExtra("data", "android-fxa-subscribe");
+    final AndroidFxAccount fxAccount = AndroidFxAccount.fromContext(context);
+    geckoIntent.putExtra("org.mozilla.gecko.intent.PROFILE_NAME", fxAccount.getProfile());
+    context.startService(geckoIntent);
+    // -> handleMessage()
+  }
+
+  @Override
+  public void handleMessage(String event, Bundle message, EventCallback callback) {
+    if ("FxAccountsPush:Subscribe:Response".equals(event)) {
+      try {
+        doFxaRegistration(message.getBundle("subscription"));
+      } catch (InvalidFxAState e) {
+        Log.d(LOG_TAG, "Invalid state when trying to register with FxA ", e);
+      }
+    } else {
+      Log.e(LOG_TAG, "No action defined for " + event);
+    }
+  }
+
+  private void doFxaRegistration(Bundle subscription) throws InvalidFxAState {
+    final Context context = this.context.get();
+    if (this.context == null) {
+      throw new IllegalStateException("Application context has been gc'ed");
+    }
+    doFxaRegistration(context, subscription, true);
+  }
+
+  private static void doFxaRegistration(final Context context, final Bundle subscription, final boolean allowRecursion) throws InvalidFxAState {
+    String pushCallback = subscription.getString("pushCallback");
+    String pushPublicKey = subscription.getString("pushPublicKey");
+    String pushAuthKey = subscription.getString("pushAuthKey");
+
+    final AndroidFxAccount fxAccount = AndroidFxAccount.fromContext(context);
+    if (fxAccount == null) {
+      Log.e(LOG_TAG, "AndroidFxAccount is null");
+      return;
+    }
+    final byte[] sessionToken = fxAccount.getSessionToken();
+    final FxAccountDevice device;
+    String deviceId = fxAccount.getDeviceId();
+    String clientName = getClientName(fxAccount, context);
+    if (TextUtils.isEmpty(deviceId)) {
+      Log.i(LOG_TAG, "Attempting registration for a new device");
+      device = FxAccountDevice.forRegister(clientName, "mobile", pushCallback, pushPublicKey, pushAuthKey);
+    } else {
+      Log.i(LOG_TAG, "Attempting registration for an existing device");
+      Logger.pii(LOG_TAG, "Device ID: " + deviceId);
+      device = FxAccountDevice.forUpdate(deviceId, clientName, pushCallback, pushPublicKey, pushAuthKey);
+    }
+
+    ExecutorService executor = Executors.newSingleThreadExecutor(); // Not called often, it's okay to spawn another thread
+    final FxAccountClient20 fxAccountClient =
+            new FxAccountClient20(fxAccount.getAccountServerURI(), executor);
+    fxAccountClient.registerOrUpdateDevice(sessionToken, device, new RequestDelegate<FxAccountDevice>() {
+      @Override
+      public void handleError(Exception e) {
+        Log.e(LOG_TAG, "Error while updating a device registration: ", e);
+      }
+
+      @Override
+      public void handleFailure(FxAccountClientRemoteException error) {
+        Log.e(LOG_TAG, "Error while updating a device registration: ", error);
+        if (error.httpStatusCode == 400) {
+          if (error.apiErrorNumber == FxAccountRemoteError.UNKNOWN_DEVICE) {
+            recoverFromUnknownDevice(fxAccount);
+          } else if (error.apiErrorNumber == FxAccountRemoteError.DEVICE_SESSION_CONFLICT) {
+            recoverFromDeviceSessionConflict(error, fxAccountClient, sessionToken, fxAccount, context,
+                    subscription, allowRecursion);
+          }
+        } else
+        if (error.httpStatusCode == 401
+                && error.apiErrorNumber == FxAccountRemoteError.INVALID_AUTHENTICATION_TOKEN) {
+          handleTokenError(error, fxAccountClient, fxAccount);
+        } else {
+          logErrorAndResetDeviceRegistrationVersion(error, fxAccount);
+        }
+      }
+
+      @Override
+      public void handleSuccess(FxAccountDevice result) {
+        Log.i(LOG_TAG, "Device registration complete");
+        Logger.pii(LOG_TAG, "Registered device ID: " + result.id);
+        fxAccount.setFxAUserData(result.id, DEVICE_REGISTRATION_VERSION);
+      }
+    });
+  }
+
+  private static void logErrorAndResetDeviceRegistrationVersion(
+      final FxAccountClientRemoteException error, final AndroidFxAccount fxAccount) {
+    Log.e(LOG_TAG, "Device registration failed", error);
+    fxAccount.resetDeviceRegistrationVersion();
+  }
+
+  @Nullable
+  private static String getClientName(final AndroidFxAccount fxAccount, final Context context) {
+    try {
+      SharedPreferencesClientsDataDelegate clientsDataDelegate =
+          new SharedPreferencesClientsDataDelegate(fxAccount.getSyncPrefs(), context);
+      return clientsDataDelegate.getClientName();
+    } catch (UnsupportedEncodingException | GeneralSecurityException e) {
+      Log.e(LOG_TAG, "Unable to get client name.", e);
+      return null;
+    }
+  }
+
+  private static void handleTokenError(final FxAccountClientRemoteException error,
+                                       final FxAccountClient fxAccountClient,
+                                       final AndroidFxAccount fxAccount) {
+    Log.i(LOG_TAG, "Recovering from invalid token error: ", error);
+    logErrorAndResetDeviceRegistrationVersion(error, fxAccount);
+    fxAccountClient.accountStatus(fxAccount.getState().uid,
+        new RequestDelegate<AccountStatusResponse>() {
+      @Override
+      public void handleError(Exception e) {
+      }
+
+      @Override
+      public void handleFailure(FxAccountClientRemoteException e) {
+      }
+
+      @Override
+      public void handleSuccess(AccountStatusResponse result) {
+        State doghouseState = fxAccount.getState().makeDoghouseState();
+        if (!result.exists) {
+          Log.i(LOG_TAG, "token invalidated because the account no longer exists");
+          // TODO: Should be in a "I have an Android account, but the FxA is gone." State.
+          // This will do for now..
+          fxAccount.setState(doghouseState);
+          return;
+        }
+        Log.e(LOG_TAG, "sessionToken invalid");
+        fxAccount.setState(doghouseState);
+      }
+    });
+  }
+
+  private static void recoverFromUnknownDevice(final AndroidFxAccount fxAccount) {
+    Log.i(LOG_TAG, "unknown device id, clearing the cached device id");
+    fxAccount.setDeviceId(null);
+  }
+
+  /**
+   * Will call delegate#complete in all cases
+   */
+  private static void recoverFromDeviceSessionConflict(final FxAccountClientRemoteException error,
+                                                       final FxAccountClient fxAccountClient,
+                                                       final byte[] sessionToken,
+                                                       final AndroidFxAccount fxAccount,
+                                                       final Context context,
+                                                       final Bundle subscription,
+                                                       final boolean allowRecursion) {
+    Log.w(LOG_TAG, "device session conflict, attempting to ascertain the correct device id");
+    fxAccountClient.deviceList(sessionToken, new RequestDelegate<FxAccountDevice[]>() {
+      private void onError() {
+        Log.e(LOG_TAG, "failed to recover from device-session conflict");
+        logErrorAndResetDeviceRegistrationVersion(error, fxAccount);
+      }
+
+      @Override
+      public void handleError(Exception e) {
+        onError();
+      }
+
+      @Override
+      public void handleFailure(FxAccountClientRemoteException e) {
+        onError();
+      }
+
+      @Override
+      public void handleSuccess(FxAccountDevice[] devices) {
+        for (FxAccountDevice device : devices) {
+          if (device.isCurrentDevice) {
+            fxAccount.setFxAUserData(device.id, 0); // Reset device registration version
+            if (!allowRecursion) {
+              Log.d(LOG_TAG, "Failure to register a device on the second try");
+              break;
+            }
+            try {
+              doFxaRegistration(context, subscription, false);
+              return;
+            } catch (InvalidFxAState e) {
+              Log.d(LOG_TAG, "Invalid state when trying to recover from a session conflict ", e);
+              break;
+            }
+          }
+        }
+        onError();
+      }
+    });
+  }
+
+  private void setupListeners() throws ClassNotFoundException, NoSuchMethodException,
+          InvocationTargetException, IllegalAccessException {
+    // We have no choice but to use reflection here, sorry :(
+    Class<?> eventDispatcher = Class.forName("org.mozilla.gecko.EventDispatcher");
+    Method getInstance = eventDispatcher.getMethod("getInstance");
+    Object instance = getInstance.invoke(null);
+    Method registerBackgroundThreadListener = eventDispatcher.getMethod("registerBackgroundThreadListener",
+            BundleEventListener.class, String[].class);
+    registerBackgroundThreadListener.invoke(instance, this, new String[] { "FxAccountsPush:Subscribe:Response" });
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountPushHandler.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountPushHandler.java
new file mode 100644
index 000000000..0117e6320
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/FxAccountPushHandler.java
@@ -0,0 +1,95 @@
+package org.mozilla.gecko.fxa;
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.content.Context;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.util.Log;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+
+public class FxAccountPushHandler {
+    private static final String LOG_TAG = "FxAccountPush";
+
+    private static final String COMMAND_DEVICE_DISCONNECTED = "fxaccounts:device_disconnected";
+    private static final String COMMAND_COLLECTION_CHANGED = "sync:collection_changed";
+
+    private static final String CLIENTS_COLLECTION = "clients";
+
+    // Forbid instantiation
+    private FxAccountPushHandler() {}
+
+    public static void handleFxAPushMessage(Context context, Bundle bundle) {
+        Log.i(LOG_TAG, "Handling FxA Push Message");
+        String rawMessage = bundle.getString("message");
+        JSONObject message = null;
+        if (!TextUtils.isEmpty(rawMessage)) {
+            try {
+                message = new JSONObject(rawMessage);
+            } catch (JSONException e) {
+                Log.e(LOG_TAG, "Could not parse JSON", e);
+                return;
+            }
+        }
+        if (message == null) {
+            // An empty body means we should check the verification state of the account (FxA sends this
+            // when the account email is verified for example).
+            // TODO: We're only registering the push endpoint when we are in the Married state, that's why we're skipping the message :(
+            Log.d(LOG_TAG, "Skipping empty message");
+            return;
+        }
+        try {
+            String command = message.getString("command");
+            JSONObject data = message.getJSONObject("data");
+            switch (command) {
+                case COMMAND_DEVICE_DISCONNECTED:
+                    handleDeviceDisconnection(context, data);
+                    break;
+                case COMMAND_COLLECTION_CHANGED:
+                    handleCollectionChanged(context, data);
+                    break;
+                default:
+                    Log.d(LOG_TAG, "No handler defined for FxA Push command " + command);
+                    break;
+            }
+        } catch (JSONException e) {
+            Log.e(LOG_TAG, "Error while handling FxA push notification", e);
+        }
+    }
+
+    private static void handleCollectionChanged(Context context, JSONObject data) throws JSONException {
+        JSONArray collections = data.getJSONArray("collections");
+        int len = collections.length();
+        for (int i = 0; i < len; i++) {
+            if (collections.getString(i).equals(CLIENTS_COLLECTION)) {
+                final Account account = FirefoxAccounts.getFirefoxAccount(context);
+                if (account == null) {
+                    Log.e(LOG_TAG, "The account does not exist anymore");
+                    return;
+                }
+                final AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+                fxAccount.requestImmediateSync(new String[] { CLIENTS_COLLECTION }, null);
+                return;
+            }
+        }
+    }
+
+    private static void handleDeviceDisconnection(Context context, JSONObject data) throws JSONException {
+        final Account account = FirefoxAccounts.getFirefoxAccount(context);
+        if (account == null) {
+            Log.e(LOG_TAG, "The account does not exist anymore");
+            return;
+        }
+        final AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+        if (!fxAccount.getDeviceId().equals(data.getString("id"))) {
+            Log.e(LOG_TAG, "The device ID to disconnect doesn't match with the local device ID.\n"
+                            + "Local: " + fxAccount.getDeviceId() + ", ID to disconnect: " + data.getString("id"));
+            return;
+        }
+        AccountManager.get(context).removeAccount(account, null, null);
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/SyncStatusListener.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/SyncStatusListener.java
new file mode 100644
index 000000000..2f70a363a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/SyncStatusListener.java
@@ -0,0 +1,31 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa;
+
+import android.accounts.Account;
+import android.content.Context;
+import android.support.annotation.UiThread;
+
+/**
+ * Interface definition for a callback to be invoked when an sync status change.
+ */
+public interface SyncStatusListener {
+    public Context getContext();
+    public Account getAccount();
+
+    /**
+     * Called when sync has started.
+     * This is always called in UiThread.
+     */
+    @UiThread
+    public void onSyncStarted();
+
+    /**
+     * Called when sync has finished.
+     * This is always called in UiThread.
+     */
+    @UiThread
+    public void onSyncFinished();
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/CustomColorPreference.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/CustomColorPreference.java
new file mode 100644
index 000000000..5c4d7f3cc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/CustomColorPreference.java
@@ -0,0 +1,52 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+import org.mozilla.gecko.R;
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.preference.Preference;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.TextView;
+
+ /**
+  * This preference is used to define custom  colors for both title and summary texts.
+  * Color code #777777 (placeholder_grey) is used as the fallback color for both title and summary.
+  */
+public class CustomColorPreference extends Preference {
+    private int mTitleColor;
+    private int mSummaryColor;
+
+    public CustomColorPreference(Context context) {
+        super(context);
+    }
+
+    public CustomColorPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        init(context, attrs);
+    }
+
+    public CustomColorPreference(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        init(context, attrs);
+    }
+
+    public void init(Context context, AttributeSet attrs) {
+        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CustomColorPreference);
+        mTitleColor = a.getColor(R.styleable.CustomColorPreference_titleColor, R.color.placeholder_grey);
+        mSummaryColor = a.getColor(R.styleable.CustomColorPreference_summaryColor, R.color.placeholder_grey);
+        a.recycle();
+    }
+
+    @Override
+    protected void onBindView(View view) {
+        super.onBindView(view);
+        final TextView title = (TextView) view.findViewById(android.R.id.title);
+        final TextView summary = (TextView) view.findViewById(android.R.id.summary);
+        title.setTextColor(mTitleColor);
+        summary.setTextColor(mSummaryColor);
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountAbstractActivity.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountAbstractActivity.java
new file mode 100644
index 000000000..fc8cbf0da
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountAbstractActivity.java
@@ -0,0 +1,80 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+import android.accounts.Account;
+import android.app.Activity;
+import android.content.Intent;
+
+import org.mozilla.gecko.Locales.LocaleAwareActivity;
+import org.mozilla.gecko.fxa.FirefoxAccounts;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+
+public abstract class FxAccountAbstractActivity extends LocaleAwareActivity {
+  private static final String LOG_TAG = FxAccountAbstractActivity.class.getSimpleName();
+
+  protected final boolean cannotResumeWhenAccountsExist;
+  protected final boolean cannotResumeWhenNoAccountsExist;
+
+  public static final int CAN_ALWAYS_RESUME = 0;
+  public static final int CANNOT_RESUME_WHEN_ACCOUNTS_EXIST = 1 << 0;
+  public static final int CANNOT_RESUME_WHEN_NO_ACCOUNTS_EXIST = 1 << 1;
+
+  public FxAccountAbstractActivity(int resume) {
+    super();
+    this.cannotResumeWhenAccountsExist = 0 != (resume & CANNOT_RESUME_WHEN_ACCOUNTS_EXIST);
+    this.cannotResumeWhenNoAccountsExist = 0 != (resume & CANNOT_RESUME_WHEN_NO_ACCOUNTS_EXIST);
+  }
+
+  /**
+   * Many Firefox Accounts activities shouldn't display if an account already
+   * exists. This function redirects as appropriate.
+   *
+   * @return true if redirected.
+   */
+  protected boolean redirectIfAppropriate() {
+    if (cannotResumeWhenAccountsExist || cannotResumeWhenNoAccountsExist) {
+      final Account account = FirefoxAccounts.getFirefoxAccount(this);
+      if (cannotResumeWhenAccountsExist && account != null) {
+        redirectToAction(FxAccountConstants.ACTION_FXA_STATUS);
+        return true;
+      }
+      if (cannotResumeWhenNoAccountsExist && account == null) {
+        redirectToAction(FxAccountConstants.ACTION_FXA_GET_STARTED);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  @Override
+  public void onResume() {
+    super.onResume();
+    redirectIfAppropriate();
+  }
+
+  @Override
+  public void onBackPressed() {
+      super.onBackPressed();
+      overridePendingTransition(0, 0);
+  }
+
+  protected void launchActivity(Class<? extends Activity> activityClass) {
+    Intent intent = new Intent(this, activityClass);
+    // Per http://stackoverflow.com/a/8992365, this triggers a known bug with
+    // the soft keyboard not being shown for the started activity. Why, Android, why?
+    intent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
+    startActivity(intent);
+  }
+
+  protected void redirectToAction(final String action) {
+    final Intent intent = new Intent(action);
+    // Per http://stackoverflow.com/a/8992365, this triggers a known bug with
+    // the soft keyboard not being shown for the started activity. Why, Android, why?
+    intent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
+    startActivity(intent);
+    finish();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountConfirmAccountActivityWeb.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountConfirmAccountActivityWeb.java
new file mode 100644
index 000000000..b2afd9c5a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountConfirmAccountActivityWeb.java
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+public class FxAccountConfirmAccountActivityWeb extends FxAccountWebFlowActivity {
+  public FxAccountConfirmAccountActivityWeb() {
+    super(CANNOT_RESUME_WHEN_NO_ACCOUNTS_EXIST, "manage");
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountFinishMigratingActivityWeb.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountFinishMigratingActivityWeb.java
new file mode 100644
index 000000000..0e66f1d6c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountFinishMigratingActivityWeb.java
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+public class FxAccountFinishMigratingActivityWeb extends FxAccountWebFlowActivity {
+  public FxAccountFinishMigratingActivityWeb() {
+    super(CANNOT_RESUME_WHEN_NO_ACCOUNTS_EXIST, "signin", "migration=sync11");
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountGetStartedActivityWeb.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountGetStartedActivityWeb.java
new file mode 100644
index 000000000..39a907a44
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountGetStartedActivityWeb.java
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+public class FxAccountGetStartedActivityWeb extends FxAccountWebFlowActivity {
+  public FxAccountGetStartedActivityWeb() {
+    super(CANNOT_RESUME_WHEN_ACCOUNTS_EXIST, "signup");
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountStatusActivity.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountStatusActivity.java
new file mode 100644
index 000000000..4bb929f0a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountStatusActivity.java
@@ -0,0 +1,228 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.accounts.AccountManagerCallback;
+import android.accounts.AccountManagerFuture;
+import android.annotation.SuppressLint;
+import android.annotation.TargetApi;
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.os.Build;
+import android.os.Bundle;
+import android.support.v7.app.ActionBar;
+import android.support.v7.widget.Toolbar;
+import android.util.TypedValue;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.Window;
+import android.widget.Toast;
+import org.mozilla.gecko.AppConstants;
+import org.mozilla.gecko.Locales.LocaleAwareAppCompatActivity;
+import org.mozilla.gecko.R;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.fxa.FirefoxAccounts;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.sync.Utils;
+
+/**
+ * Activity which displays account status.
+ */
+public class FxAccountStatusActivity extends LocaleAwareAppCompatActivity {
+  private static final String LOG_TAG = FxAccountStatusActivity.class.getSimpleName();
+
+  protected FxAccountStatusFragment statusFragment;
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+
+    // Display the fragment as the content.
+    statusFragment = new FxAccountStatusFragment();
+    getSupportFragmentManager()
+      .beginTransaction()
+      .replace(android.R.id.content, statusFragment)
+      .commit();
+
+    maybeSetHomeButtonEnabled();
+  }
+
+  /**
+   * Sufficiently recent Android versions need additional code to receive taps
+   * on the status bar to go "up". See <a
+   * href="http://stackoverflow.com/a/8953148">this stackoverflow answer</a> for
+   * more information.
+   */
+  @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
+  protected void maybeSetHomeButtonEnabled() {
+    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
+      Logger.debug(LOG_TAG, "Not enabling home button; version too low.");
+      return;
+    }
+    final ActionBar actionBar = getSupportActionBar();
+    if (actionBar != null) {
+      Logger.debug(LOG_TAG, "Enabling home button.");
+      actionBar.setHomeButtonEnabled(true);
+      actionBar.setDisplayHomeAsUpEnabled(true);
+      return;
+    }
+    Logger.debug(LOG_TAG, "Not enabling home button.");
+  }
+
+  @Override
+  public void onResume() {
+    super.onResume();
+
+    final AndroidFxAccount fxAccount = getAndroidFxAccount();
+    if (fxAccount == null) {
+      Logger.warn(LOG_TAG, "Could not get Firefox Account.");
+
+      // Gracefully redirect to get started.
+      final Intent intent = new Intent(FxAccountConstants.ACTION_FXA_GET_STARTED);
+      // Per http://stackoverflow.com/a/8992365, this triggers a known bug with
+      // the soft keyboard not being shown for the started activity. Why, Android, why?
+      intent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
+      startActivity(intent);
+
+      setResult(RESULT_CANCELED);
+      finish();
+      return;
+    }
+    statusFragment.refresh(fxAccount);
+  }
+
+  /**
+   * Helper to fetch (unique) Android Firefox Account if one exists, or return null.
+   */
+  protected AndroidFxAccount getAndroidFxAccount() {
+    Account account = FirefoxAccounts.getFirefoxAccount(this);
+    if (account == null) {
+      return null;
+    }
+    return new AndroidFxAccount(this, account);
+  }
+
+
+  /**
+   * Helper function to maybe remove the given Android account.
+   */
+  @SuppressLint("InlinedApi")
+  public static void maybeDeleteAndroidAccount(final Activity activity, final Account account, final Intent intent) {
+    if (account == null) {
+      Logger.warn(LOG_TAG, "Trying to delete null account; ignoring request.");
+      return;
+    }
+
+    final AccountManagerCallback<Boolean> callback = new AccountManagerCallback<Boolean>() {
+      @Override
+      public void run(AccountManagerFuture<Boolean> future) {
+        Logger.info(LOG_TAG, "Account " + Utils.obfuscateEmail(account.name) + " removed.");
+        final String text = activity.getResources().getString(R.string.fxaccount_remove_account_toast, account.name);
+        Toast.makeText(activity, text, Toast.LENGTH_LONG).show();
+        if (intent != null) {
+            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+            activity.startActivity(intent);
+        }
+        activity.finish();
+      }
+    };
+
+    /*
+     * Get the best dialog icon from the theme on v11+.
+     * See http://stackoverflow.com/questions/14910536/android-dialog-theme-makes-icon-too-light/14910945#14910945.
+     */
+    final int icon;
+    final TypedValue typedValue = new TypedValue();
+    activity.getTheme().resolveAttribute(android.R.attr.alertDialogIcon, typedValue, true);
+    icon = typedValue.resourceId;
+
+    final AlertDialog dialog = new AlertDialog.Builder(activity)
+      .setTitle(R.string.fxaccount_remove_account_dialog_title)
+      .setIcon(icon)
+      .setMessage(R.string.fxaccount_remove_account_dialog_message)
+      .setPositiveButton(android.R.string.ok, new Dialog.OnClickListener() {
+        @Override
+        public void onClick(DialogInterface dialog, int which) {
+          AccountManager.get(activity).removeAccount(account, callback, null);
+        }
+      })
+      .setNegativeButton(android.R.string.cancel, new Dialog.OnClickListener() {
+        @Override
+        public void onClick(DialogInterface dialog, int which) {
+          dialog.cancel();
+        }
+      })
+      .create();
+
+    dialog.show();
+  }
+
+  @Override
+  public boolean onOptionsItemSelected(MenuItem item) {
+    int itemId = item.getItemId();
+    if (itemId == android.R.id.home) {
+      finish();
+      return true;
+    }
+
+    if (itemId == R.id.enable_debug_mode) {
+      FxAccountUtils.LOG_PERSONAL_INFORMATION = !FxAccountUtils.LOG_PERSONAL_INFORMATION;
+      Toast.makeText(this, (FxAccountUtils.LOG_PERSONAL_INFORMATION ? "Enabled" : "Disabled") +
+          " Firefox Account personal information!", Toast.LENGTH_LONG).show();
+      item.setChecked(!item.isChecked());
+      // Display or hide debug options.
+      statusFragment.hardRefresh();
+      return true;
+    }
+
+    return super.onOptionsItemSelected(item);
+  }
+
+  @Override
+  public boolean onCreateOptionsMenu(Menu menu) {
+    final MenuInflater inflater = getMenuInflater();
+    inflater.inflate(R.menu.fxaccount_status_menu, menu);
+    // !defined(MOZILLA_OFFICIAL) || defined(NIGHTLY_BUILD) || defined(MOZ_DEBUG)
+    boolean enabled = !AppConstants.MOZILLA_OFFICIAL || AppConstants.NIGHTLY_BUILD || AppConstants.DEBUG_BUILD;
+    if (!enabled) {
+      menu.removeItem(R.id.enable_debug_mode);
+    } else {
+      final MenuItem debugModeItem = menu.findItem(R.id.enable_debug_mode);
+      if (debugModeItem != null) {
+        // Update checked state based on internal flag.
+        menu.findItem(R.id.enable_debug_mode).setChecked(FxAccountUtils.LOG_PERSONAL_INFORMATION);
+      }
+    }
+    return super.onCreateOptionsMenu(menu);
+  };
+
+  @Override
+  public void openOptionsMenu() {
+    // This is a workaround of an Android bug:
+    // https://code.google.com/p/android/issues/detail?id=185217
+    // openOptionsMenu isn't overriden by WindowDecorActionBar, which is used by AppCompatActivity,
+    // meaning getSupportActionbar().openOptionsMenu doesn't work.
+    // Based loosely on the code in:
+    // http://androidxref.com/6.0.1_r10/xref/frameworks/support/v7/appcompat/src/android/support/v7/internal/app/WindowDecorActionBar.java#getDecorToolbar
+
+    final Window window = getWindow();
+    final View decor = window.getDecorView();
+    final View view = decor.findViewById(R.id.action_bar);
+
+    if (view instanceof Toolbar) {
+      final Toolbar toolbar = (Toolbar) view;
+      toolbar.showOverflowMenu();
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountStatusFragment.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountStatusFragment.java
new file mode 100644
index 000000000..a30b92e5f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountStatusFragment.java
@@ -0,0 +1,949 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+import android.accounts.Account;
+import android.content.BroadcastReceiver;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.content.SharedPreferences;
+import android.os.Bundle;
+import android.os.Handler;
+import android.preference.CheckBoxPreference;
+import android.preference.EditTextPreference;
+import android.preference.Preference;
+import android.preference.Preference.OnPreferenceChangeListener;
+import android.preference.Preference.OnPreferenceClickListener;
+import android.preference.PreferenceCategory;
+import android.preference.PreferenceScreen;
+import android.support.v4.content.LocalBroadcastManager;
+import android.text.TextUtils;
+import android.text.format.DateUtils;
+
+import com.squareup.picasso.Picasso;
+import com.squareup.picasso.Target;
+
+import org.mozilla.gecko.AppConstants;
+import org.mozilla.gecko.R;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.background.preferences.PreferenceFragment;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.fxa.SyncStatusListener;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.fxa.login.Married;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.fxa.sync.FxAccountSyncStatusHelper;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.SharedPreferencesClientsDataDelegate;
+import org.mozilla.gecko.sync.SyncConfiguration;
+import org.mozilla.gecko.sync.setup.activities.ActivityUtils;
+import org.mozilla.gecko.util.HardwareUtils;
+import org.mozilla.gecko.util.ThreadUtils;
+
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * A fragment that displays the status of an AndroidFxAccount.
+ * <p>
+ * The owning activity is responsible for providing an AndroidFxAccount at
+ * appropriate times.
+ */
+public class FxAccountStatusFragment
+    extends PreferenceFragment
+    implements OnPreferenceClickListener, OnPreferenceChangeListener {
+  private static final String LOG_TAG = FxAccountStatusFragment.class.getSimpleName();
+
+  /**
+   * If a device claims to have synced before this date, we will assume it has never synced.
+   */
+  private static final Date EARLIEST_VALID_SYNCED_DATE;
+
+  static {
+    final Calendar c = GregorianCalendar.getInstance();
+    c.set(2000, Calendar.JANUARY, 1, 0, 0, 0);
+    EARLIEST_VALID_SYNCED_DATE = c.getTime();
+  }
+
+  // When a checkbox is toggled, wait 5 seconds (for other checkbox actions)
+  // before trying to sync. Should we kill off the fragment before the sync
+  // request happens, that's okay: the runnable will run if the UI thread is
+  // still around to service it, and since we're not updating any UI, we'll just
+  // schedule the sync as usual. See also comment below about garbage
+  // collection.
+  private static final long DELAY_IN_MILLISECONDS_BEFORE_REQUESTING_SYNC = 5 * 1000;
+  private static final long LAST_SYNCED_TIME_UPDATE_INTERVAL_IN_MILLISECONDS = 60 * 1000;
+  private static final long PROFILE_FETCH_RETRY_INTERVAL_IN_MILLISECONDS = 60 * 1000;
+
+  private static final String[] STAGES_TO_SYNC_ON_DEVICE_NAME_CHANGE = new String[] { "clients" };
+
+  // By default, the auth/account server preference is only shown when the
+  // account is configured to use a custom server. In debug mode, this is set.
+  private static boolean ALWAYS_SHOW_AUTH_SERVER = false;
+
+  // By default, the Sync server preference is only shown when the account is
+  // configured to use a custom Sync server. In debug mode, this is set.
+  private static boolean ALWAYS_SHOW_SYNC_SERVER = false;
+
+  protected PreferenceCategory accountCategory;
+  protected Preference profilePreference;
+  protected Preference manageAccountPreference;
+  protected Preference authServerPreference;
+  protected Preference removeAccountPreference;
+
+  protected Preference needsPasswordPreference;
+  protected Preference needsUpgradePreference;
+  protected Preference needsVerificationPreference;
+  protected Preference needsMasterSyncAutomaticallyEnabledPreference;
+  protected Preference needsFinishMigratingPreference;
+
+  protected PreferenceCategory syncCategory;
+
+  protected CheckBoxPreference bookmarksPreference;
+  protected CheckBoxPreference historyPreference;
+  protected CheckBoxPreference tabsPreference;
+  protected CheckBoxPreference passwordsPreference;
+  protected CheckBoxPreference readingListPreference;
+
+  protected EditTextPreference deviceNamePreference;
+  protected Preference syncServerPreference;
+  protected Preference morePreference;
+  protected Preference syncNowPreference;
+
+  protected volatile AndroidFxAccount fxAccount;
+  // The contract is: when fxAccount is non-null, then clientsDataDelegate is
+  // non-null.  If violated then an IllegalStateException is thrown.
+  protected volatile SharedPreferencesClientsDataDelegate clientsDataDelegate;
+
+  // Used to post delayed sync requests.
+  protected Handler handler;
+
+  // Member variable so that re-posting pushes back the already posted instance.
+  // This Runnable references the fxAccount above, but it is not specific to a
+  // single account. (That is, it does not capture a single account instance.)
+  protected Runnable requestSyncRunnable;
+
+  // Runnable to update last synced time.
+  protected Runnable lastSyncedTimeUpdateRunnable;
+
+  // Broadcast Receiver to update profile Information.
+  protected FxAccountProfileInformationReceiver accountProfileInformationReceiver;
+
+  protected final InnerSyncStatusDelegate syncStatusDelegate = new InnerSyncStatusDelegate();
+  private Target profileAvatarTarget;
+
+  protected Preference ensureFindPreference(String key) {
+    Preference preference = findPreference(key);
+    if (preference == null) {
+      throw new IllegalStateException("Could not find preference with key: " + key);
+    }
+    return preference;
+  }
+
+  @Override
+  public void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+
+    // We need to do this before we can query the hardware menu button state.
+    // We're guaranteed to have an activity at this point (onAttach is called
+    // before onCreate). It's okay to call this multiple times (with different
+    // contexts).
+    HardwareUtils.init(getActivity());
+
+    addPreferences();
+  }
+
+  protected void addPreferences() {
+    addPreferencesFromResource(R.xml.fxaccount_status_prefscreen);
+
+    accountCategory = (PreferenceCategory) ensureFindPreference("signed_in_as_category");
+    profilePreference = ensureFindPreference("profile");
+    manageAccountPreference = ensureFindPreference("manage_account");
+    authServerPreference = ensureFindPreference("auth_server");
+    removeAccountPreference = ensureFindPreference("remove_account");
+
+    needsPasswordPreference = ensureFindPreference("needs_credentials");
+    needsUpgradePreference = ensureFindPreference("needs_upgrade");
+    needsVerificationPreference = ensureFindPreference("needs_verification");
+    needsMasterSyncAutomaticallyEnabledPreference = ensureFindPreference("needs_master_sync_automatically_enabled");
+    needsFinishMigratingPreference = ensureFindPreference("needs_finish_migrating");
+
+    syncCategory = (PreferenceCategory) ensureFindPreference("sync_category");
+
+    bookmarksPreference = (CheckBoxPreference) ensureFindPreference("bookmarks");
+    historyPreference = (CheckBoxPreference) ensureFindPreference("history");
+    tabsPreference = (CheckBoxPreference) ensureFindPreference("tabs");
+    passwordsPreference = (CheckBoxPreference) ensureFindPreference("passwords");
+
+    if (!FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+      removeDebugButtons();
+    } else {
+      connectDebugButtons();
+      ALWAYS_SHOW_AUTH_SERVER = true;
+      ALWAYS_SHOW_SYNC_SERVER = true;
+    }
+
+    profilePreference.setOnPreferenceClickListener(this);
+    manageAccountPreference.setOnPreferenceClickListener(this);
+    removeAccountPreference.setOnPreferenceClickListener(this);
+
+    needsPasswordPreference.setOnPreferenceClickListener(this);
+    needsVerificationPreference.setOnPreferenceClickListener(this);
+    needsFinishMigratingPreference.setOnPreferenceClickListener(this);
+
+    bookmarksPreference.setOnPreferenceClickListener(this);
+    historyPreference.setOnPreferenceClickListener(this);
+    tabsPreference.setOnPreferenceClickListener(this);
+    passwordsPreference.setOnPreferenceClickListener(this);
+
+    deviceNamePreference = (EditTextPreference) ensureFindPreference("device_name");
+    deviceNamePreference.setOnPreferenceChangeListener(this);
+
+    syncServerPreference = ensureFindPreference("sync_server");
+    morePreference = ensureFindPreference("more");
+    morePreference.setOnPreferenceClickListener(this);
+
+    syncNowPreference = ensureFindPreference("sync_now");
+    syncNowPreference.setEnabled(true);
+    syncNowPreference.setOnPreferenceClickListener(this);
+
+    ensureFindPreference("linktos").setOnPreferenceClickListener(this);
+    ensureFindPreference("linkprivacy").setOnPreferenceClickListener(this);
+  }
+
+  /**
+   * We intentionally don't refresh here. Our owning activity is responsible for
+   * providing an AndroidFxAccount to our refresh method in its onResume method.
+   */
+  @Override
+  public void onResume() {
+    super.onResume();
+  }
+
+  @Override
+  public boolean onPreferenceClick(Preference preference) {
+    if (preference == profilePreference) {
+      ActivityUtils.openURLInFennec(getActivity().getApplicationContext(), "about:accounts?action=avatar");
+      return true;
+    }
+
+    if (preference == manageAccountPreference) {
+      ActivityUtils.openURLInFennec(getActivity().getApplicationContext(), "about:accounts?action=manage");
+      return true;
+    }
+
+    if (preference == removeAccountPreference) {
+      FxAccountStatusActivity.maybeDeleteAndroidAccount(getActivity(), fxAccount.getAndroidAccount(), null);
+      return true;
+    }
+
+    if (preference == needsPasswordPreference) {
+      final Intent intent = new Intent(FxAccountConstants.ACTION_FXA_UPDATE_CREDENTIALS);
+      intent.putExtra(FxAccountWebFlowActivity.EXTRA_ENDPOINT, FxAccountConstants.ENDPOINT_PREFERENCES);
+      // Per http://stackoverflow.com/a/8992365, this triggers a known bug with
+      // the soft keyboard not being shown for the started activity. Why, Android, why?
+      intent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
+      startActivity(intent);
+
+      return true;
+    }
+
+    if (preference == needsFinishMigratingPreference) {
+      final Intent intent = new Intent(FxAccountConstants.ACTION_FXA_FINISH_MIGRATING);
+      intent.putExtra(FxAccountWebFlowActivity.EXTRA_ENDPOINT, FxAccountConstants.ENDPOINT_PREFERENCES);
+      // Per http://stackoverflow.com/a/8992365, this triggers a known bug with
+      // the soft keyboard not being shown for the started activity. Why, Android, why?
+      intent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
+      startActivity(intent);
+
+      return true;
+    }
+
+    if (preference == needsVerificationPreference) {
+      final Intent intent = new Intent(FxAccountConstants.ACTION_FXA_CONFIRM_ACCOUNT);
+      // Per http://stackoverflow.com/a/8992365, this triggers a known bug with
+      // the soft keyboard not being shown for the started activity. Why, Android, why?
+      intent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
+      intent.putExtra(FxAccountWebFlowActivity.EXTRA_ENDPOINT, FxAccountConstants.ENDPOINT_PREFERENCES);
+      startActivity(intent);
+
+      return true;
+    }
+
+    if (preference == bookmarksPreference ||
+        preference == historyPreference ||
+        preference == passwordsPreference ||
+        preference == tabsPreference) {
+      saveEngineSelections();
+      return true;
+    }
+
+    if (preference == morePreference) {
+      getActivity().openOptionsMenu();
+      return true;
+    }
+
+    if (preference == syncNowPreference) {
+      if (fxAccount != null) {
+        fxAccount.requestImmediateSync(null, null);
+      }
+      return true;
+    }
+
+    if (TextUtils.equals("linktos", preference.getKey())) {
+      ActivityUtils.openURLInFennec(getActivity().getApplicationContext(), getResources().getString(R.string.fxaccount_link_tos));
+      return true;
+    }
+
+    if (TextUtils.equals("linkprivacy", preference.getKey())) {
+      ActivityUtils.openURLInFennec(getActivity().getApplicationContext(), getResources().getString(R.string.fxaccount_link_pn));
+      return true;
+    }
+
+    return false;
+  }
+
+  protected void setCheckboxesEnabled(boolean enabled) {
+    bookmarksPreference.setEnabled(enabled);
+    historyPreference.setEnabled(enabled);
+    tabsPreference.setEnabled(enabled);
+    passwordsPreference.setEnabled(enabled);
+    // Since we can't sync, we can't update our remote client record.
+    deviceNamePreference.setEnabled(enabled);
+    syncNowPreference.setEnabled(enabled);
+  }
+
+  /**
+   * Show at most one error preference, hiding all others.
+   *
+   * @param errorPreferenceToShow
+   *          single error preference to show; if null, hide all error preferences
+   */
+  protected void showOnlyOneErrorPreference(Preference errorPreferenceToShow) {
+    final Preference[] errorPreferences = new Preference[] {
+        this.needsPasswordPreference,
+        this.needsUpgradePreference,
+        this.needsVerificationPreference,
+        this.needsMasterSyncAutomaticallyEnabledPreference,
+        this.needsFinishMigratingPreference,
+    };
+    for (Preference errorPreference : errorPreferences) {
+      final boolean currentlyShown = null != findPreference(errorPreference.getKey());
+      final boolean shouldBeShown = errorPreference == errorPreferenceToShow;
+      if (currentlyShown == shouldBeShown) {
+        continue;
+      }
+      if (shouldBeShown) {
+        syncCategory.addPreference(errorPreference);
+      } else {
+        syncCategory.removePreference(errorPreference);
+      }
+    }
+  }
+
+  protected void showNeedsPassword() {
+    syncCategory.setTitle(R.string.fxaccount_status_sync);
+    showOnlyOneErrorPreference(needsPasswordPreference);
+    setCheckboxesEnabled(false);
+  }
+
+  protected void showNeedsUpgrade() {
+    syncCategory.setTitle(R.string.fxaccount_status_sync);
+    showOnlyOneErrorPreference(needsUpgradePreference);
+    setCheckboxesEnabled(false);
+  }
+
+  protected void showNeedsVerification() {
+    syncCategory.setTitle(R.string.fxaccount_status_sync);
+    showOnlyOneErrorPreference(needsVerificationPreference);
+    setCheckboxesEnabled(false);
+  }
+
+  protected void showNeedsMasterSyncAutomaticallyEnabled() {
+    syncCategory.setTitle(R.string.fxaccount_status_sync);
+    needsMasterSyncAutomaticallyEnabledPreference.setTitle(AppConstants.Versions.preLollipop ?
+                                                   R.string.fxaccount_status_needs_master_sync_automatically_enabled :
+                                                   R.string.fxaccount_status_needs_master_sync_automatically_enabled_v21);
+    showOnlyOneErrorPreference(needsMasterSyncAutomaticallyEnabledPreference);
+    setCheckboxesEnabled(false);
+  }
+
+  protected void showNeedsFinishMigrating() {
+    syncCategory.setTitle(R.string.fxaccount_status_sync);
+    showOnlyOneErrorPreference(needsFinishMigratingPreference);
+    setCheckboxesEnabled(false);
+  }
+
+  protected void showConnected() {
+    syncCategory.setTitle(R.string.fxaccount_status_sync_enabled);
+    showOnlyOneErrorPreference(null);
+    setCheckboxesEnabled(true);
+  }
+
+  protected class InnerSyncStatusDelegate implements SyncStatusListener {
+    protected final Runnable refreshRunnable = new Runnable() {
+      @Override
+      public void run() {
+        refresh();
+      }
+    };
+
+    @Override
+    public Context getContext() {
+      return FxAccountStatusFragment.this.getActivity();
+    }
+
+    @Override
+    public Account getAccount() {
+      return fxAccount.getAndroidAccount();
+    }
+
+    @Override
+    public void onSyncStarted() {
+      if (fxAccount == null) {
+        return;
+      }
+      Logger.info(LOG_TAG, "Got sync started message; refreshing.");
+      getActivity().runOnUiThread(refreshRunnable);
+    }
+
+    @Override
+    public void onSyncFinished() {
+      if (fxAccount == null) {
+        return;
+      }
+      Logger.info(LOG_TAG, "Got sync finished message; refreshing.");
+      getActivity().runOnUiThread(refreshRunnable);
+    }
+  }
+
+  /**
+   * Notify the fragment that a new AndroidFxAccount instance is current.
+   * <p>
+   * <b>Important:</b> call this method on the UI thread!
+   * <p>
+   * In future, this might be a Loader.
+   *
+   * @param fxAccount new instance.
+   */
+  public void refresh(AndroidFxAccount fxAccount) {
+    if (fxAccount == null) {
+      throw new IllegalArgumentException("fxAccount must not be null");
+    }
+    this.fxAccount = fxAccount;
+    try {
+      this.clientsDataDelegate = new SharedPreferencesClientsDataDelegate(fxAccount.getSyncPrefs(), getActivity().getApplicationContext());
+    } catch (Exception e) {
+      Logger.error(LOG_TAG, "Got exception fetching Sync prefs associated to Firefox Account; aborting.", e);
+      // Something is terribly wrong; best to get a stack trace rather than
+      // continue with a null clients delegate.
+      throw new IllegalStateException(e);
+    }
+
+    handler = new Handler(); // Attached to current (assumed to be UI) thread.
+
+    // Runnable is not specific to one Firefox Account. This runnable will keep
+    // a reference to this fragment alive, but we expect posted runnables to be
+    // serviced very quickly, so this is not an issue.
+    requestSyncRunnable = new RequestSyncRunnable();
+    lastSyncedTimeUpdateRunnable = new LastSyncTimeUpdateRunnable();
+
+    // We would very much like register these status observers in bookended
+    // onResume/onPause calls, but because the Fragment gets onResume during the
+    // Activity's super.onResume, it hasn't yet been told its Firefox Account.
+    // So we register the observer here (and remove it in onPause), and open
+    // ourselves to the possibility that we don't have properly paired
+    // register/unregister calls.
+    FxAccountSyncStatusHelper.getInstance().startObserving(syncStatusDelegate);
+
+    // Register a local broadcast receiver to get profile cached notification.
+    final IntentFilter intentFilter = new IntentFilter();
+    intentFilter.addAction(FxAccountConstants.ACCOUNT_PROFILE_JSON_UPDATED_ACTION);
+    accountProfileInformationReceiver = new FxAccountProfileInformationReceiver();
+    LocalBroadcastManager.getInstance(getActivity()).registerReceiver(accountProfileInformationReceiver, intentFilter);
+
+    // profilePreference is set during onCreate, so it's definitely not null here.
+    final float cornerRadius = getResources().getDimension(R.dimen.fxaccount_profile_image_width) / 2;
+    profileAvatarTarget = new PicassoPreferenceIconTarget(getResources(), profilePreference, cornerRadius);
+
+    refresh();
+  }
+
+  @Override
+  public void onPause() {
+    super.onPause();
+    FxAccountSyncStatusHelper.getInstance().stopObserving(syncStatusDelegate);
+
+    // Focus lost, remove scheduled update if any.
+    if (lastSyncedTimeUpdateRunnable != null) {
+      handler.removeCallbacks(lastSyncedTimeUpdateRunnable);
+    }
+
+    // Focus lost, unregister broadcast receiver.
+    if (accountProfileInformationReceiver != null) {
+      LocalBroadcastManager.getInstance(getActivity()).unregisterReceiver(accountProfileInformationReceiver);
+    }
+
+    if (profileAvatarTarget != null) {
+      Picasso.with(getActivity()).cancelRequest(profileAvatarTarget);
+      profileAvatarTarget = null;
+    }
+  }
+
+  protected void hardRefresh() {
+    // This is the only way to guarantee that the EditText dialogs created by
+    // EditTextPreferences are re-created. This works around the issue described
+    // at http://androiddev.orkitra.com/?p=112079.
+    final PreferenceScreen statusScreen = (PreferenceScreen) ensureFindPreference("status_screen");
+    statusScreen.removeAll();
+    addPreferences();
+
+    refresh();
+  }
+
+  protected void refresh() {
+    // refresh is called from our onResume, which can happen before the owning
+    // Activity tells us about an account (via our public
+    // refresh(AndroidFxAccount) method).
+    if (fxAccount == null) {
+      throw new IllegalArgumentException("fxAccount must not be null");
+    }
+
+    updateProfileInformation();
+    updateAuthServerPreference();
+    updateSyncServerPreference();
+
+    try {
+      // There are error states determined by Android, not the login state
+      // machine, and we have a chance to present these states here. We handle
+      // them specially, since we can't surface these states as part of syncing,
+      // because they generally stop syncs from happening regularly. Right now
+      // there are no such states.
+
+      // Interrogate the Firefox Account's state.
+      State state = fxAccount.getState();
+      switch (state.getNeededAction()) {
+      case NeedsUpgrade:
+        showNeedsUpgrade();
+        break;
+      case NeedsPassword:
+        showNeedsPassword();
+        break;
+      case NeedsVerification:
+        showNeedsVerification();
+        break;
+      case NeedsFinishMigrating:
+        showNeedsFinishMigrating();
+        break;
+      case None:
+        showConnected();
+        break;
+      }
+
+      // We check for the master setting last, since it is not strictly
+      // necessary for the user to address this error state: it's really a
+      // warning state. We surface it for the user's convenience, and to prevent
+      // confused folks wondering why Sync is not working at all.
+      final boolean masterSyncAutomatically = ContentResolver.getMasterSyncAutomatically();
+      if (!masterSyncAutomatically) {
+        showNeedsMasterSyncAutomaticallyEnabled();
+        return;
+      }
+    } finally {
+      // No matter our state, we should update the checkboxes.
+      updateSelectedEngines();
+    }
+
+    final String clientName = clientsDataDelegate.getClientName();
+    deviceNamePreference.setSummary(clientName);
+    deviceNamePreference.setText(clientName);
+
+    updateSyncNowPreference();
+  }
+
+  // This is a helper function similar to TabsAccessor.getLastSyncedString() to calculate relative "Last synced" time span.
+  private String getLastSyncedString(final long startTime) {
+    if (new Date(startTime).before(EARLIEST_VALID_SYNCED_DATE)) {
+      return getActivity().getString(R.string.fxaccount_status_never_synced);
+    }
+    final CharSequence relativeTimeSpanString = DateUtils.getRelativeTimeSpanString(startTime);
+    return getActivity().getResources().getString(R.string.fxaccount_status_last_synced, relativeTimeSpanString);
+  }
+
+  protected void updateSyncNowPreference() {
+    final boolean currentlySyncing = fxAccount.isCurrentlySyncing();
+    syncNowPreference.setEnabled(!currentlySyncing);
+    if (currentlySyncing) {
+      syncNowPreference.setTitle(R.string.fxaccount_status_syncing);
+    } else {
+      syncNowPreference.setTitle(R.string.fxaccount_status_sync_now);
+    }
+    scheduleAndUpdateLastSyncedTime();
+  }
+
+  private void updateProfileInformation() {
+
+    final ExtendedJSONObject profileJSON = fxAccount.getProfileJSON();
+    if (profileJSON == null) {
+      // Update the profile title with email as the fallback.
+      // Profile icon by default use the default avatar as the fallback.
+      profilePreference.setTitle(fxAccount.getEmail());
+      return;
+    }
+
+    updateProfileInformation(profileJSON);
+  }
+
+  /**
+   * Update profile information from json on UI thread.
+   *
+   * @param profileJSON json fetched from server.
+   */
+  protected void updateProfileInformation(final ExtendedJSONObject profileJSON) {
+    // View changes must always be done on UI thread.
+    ThreadUtils.assertOnUiThread();
+
+    FxAccountUtils.pii(LOG_TAG, "Profile JSON is: " + profileJSON.toJSONString());
+
+    final String userName = profileJSON.getString(FxAccountConstants.KEY_PROFILE_JSON_USERNAME);
+    // Update the profile username and email if available.
+    if (!TextUtils.isEmpty(userName)) {
+      profilePreference.setTitle(userName);
+      profilePreference.setSummary(fxAccount.getEmail());
+    } else {
+      profilePreference.setTitle(fxAccount.getEmail());
+    }
+
+    // Avatar URI empty, skip profile image fetch.
+    final String avatarURI = profileJSON.getString(FxAccountConstants.KEY_PROFILE_JSON_AVATAR);
+    if (TextUtils.isEmpty(avatarURI)) {
+      Logger.info(LOG_TAG, "AvatarURI is empty, skipping profile image fetch.");
+      return;
+    }
+
+    // Using noPlaceholder would avoid a pop of the default image, but it's not available in the version of Picasso
+    // we ship in the tree.
+    Picasso
+        .with(getActivity())
+        .load(avatarURI)
+        .centerInside()
+        .resizeDimen(R.dimen.fxaccount_profile_image_width, R.dimen.fxaccount_profile_image_height)
+        .placeholder(R.drawable.sync_avatar_default)
+        .error(R.drawable.sync_avatar_default)
+        .into(profileAvatarTarget);
+  }
+
+  private void scheduleAndUpdateLastSyncedTime() {
+    final String lastSynced = getLastSyncedString(fxAccount.getLastSyncedTimestamp());
+    syncNowPreference.setSummary(lastSynced);
+    handler.postDelayed(lastSyncedTimeUpdateRunnable, LAST_SYNCED_TIME_UPDATE_INTERVAL_IN_MILLISECONDS);
+  }
+
+  protected void updateAuthServerPreference() {
+    final String authServer = fxAccount.getAccountServerURI();
+    final boolean shouldBeShown = ALWAYS_SHOW_AUTH_SERVER || !FxAccountConstants.DEFAULT_AUTH_SERVER_ENDPOINT.equals(authServer);
+    final boolean currentlyShown = null != findPreference(authServerPreference.getKey());
+    if (currentlyShown != shouldBeShown) {
+      if (shouldBeShown) {
+        accountCategory.addPreference(authServerPreference);
+      } else {
+        accountCategory.removePreference(authServerPreference);
+      }
+    }
+    // Always set the summary, because on first run, the preference is visible,
+    // and the above block will be skipped if there is a custom value.
+    authServerPreference.setSummary(authServer);
+  }
+
+  protected void updateSyncServerPreference() {
+    final String syncServer = fxAccount.getTokenServerURI();
+    final boolean shouldBeShown = ALWAYS_SHOW_SYNC_SERVER || !FxAccountConstants.DEFAULT_TOKEN_SERVER_ENDPOINT.equals(syncServer);
+    final boolean currentlyShown = null != findPreference(syncServerPreference.getKey());
+    if (currentlyShown != shouldBeShown) {
+      if (shouldBeShown) {
+        syncCategory.addPreference(syncServerPreference);
+      } else {
+        syncCategory.removePreference(syncServerPreference);
+      }
+    }
+    // Always set the summary, because on first run, the preference is visible,
+    // and the above block will be skipped if there is a custom value.
+    syncServerPreference.setSummary(syncServer);
+  }
+
+  /**
+   * Query shared prefs for the current engine state, and update the UI
+   * accordingly.
+   * <p>
+   * In future, we might want this to be on a background thread, or implemented
+   * as a Loader.
+   */
+  protected void updateSelectedEngines() {
+    try {
+      SharedPreferences syncPrefs = fxAccount.getSyncPrefs();
+      Map<String, Boolean> engines = SyncConfiguration.getUserSelectedEngines(syncPrefs);
+      if (engines != null) {
+        bookmarksPreference.setChecked(engines.containsKey("bookmarks") && engines.get("bookmarks"));
+        historyPreference.setChecked(engines.containsKey("history") && engines.get("history"));
+        passwordsPreference.setChecked(engines.containsKey("passwords") && engines.get("passwords"));
+        tabsPreference.setChecked(engines.containsKey("tabs") && engines.get("tabs"));
+        return;
+      }
+
+      // We don't have user specified preferences.  Perhaps we have seen a meta/global?
+      Set<String> enabledNames = SyncConfiguration.getEnabledEngineNames(syncPrefs);
+      if (enabledNames != null) {
+        bookmarksPreference.setChecked(enabledNames.contains("bookmarks"));
+        historyPreference.setChecked(enabledNames.contains("history"));
+        passwordsPreference.setChecked(enabledNames.contains("passwords"));
+        tabsPreference.setChecked(enabledNames.contains("tabs"));
+        return;
+      }
+
+      // Okay, we don't have userSelectedEngines or enabledEngines. That means
+      // the user hasn't specified to begin with, we haven't specified here, and
+      // we haven't already seen, Sync engines. We don't know our state, so
+      // let's check everything (the default) and disable everything.
+      bookmarksPreference.setChecked(true);
+      historyPreference.setChecked(true);
+      passwordsPreference.setChecked(true);
+      tabsPreference.setChecked(true);
+      setCheckboxesEnabled(false);
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception getting engines to select; ignoring.", e);
+      return;
+    }
+  }
+
+  /**
+   * Persist engine selections to local shared preferences, and request a sync
+   * to persist selections to remote storage.
+   */
+  protected void saveEngineSelections() {
+    final Map<String, Boolean> engineSelections = new HashMap<String, Boolean>();
+    engineSelections.put("bookmarks", bookmarksPreference.isChecked());
+    engineSelections.put("history", historyPreference.isChecked());
+    engineSelections.put("passwords", passwordsPreference.isChecked());
+    engineSelections.put("tabs", tabsPreference.isChecked());
+
+    // No GlobalSession.config, so store directly to shared prefs. We do this on
+    // a background thread to avoid IO on the main thread and strict mode
+    // warnings.
+    new Thread(new PersistEngineSelectionsRunnable(engineSelections)).start();
+  }
+
+  protected void requestDelayedSync() {
+    Logger.info(LOG_TAG, "Posting a delayed request for a sync sometime soon.");
+    handler.removeCallbacks(requestSyncRunnable);
+    handler.postDelayed(requestSyncRunnable, DELAY_IN_MILLISECONDS_BEFORE_REQUESTING_SYNC);
+  }
+
+  /**
+   * Remove all traces of debug buttons. By default, no debug buttons are shown.
+   */
+  protected void removeDebugButtons() {
+    final PreferenceScreen statusScreen = (PreferenceScreen) ensureFindPreference("status_screen");
+    final PreferenceCategory debugCategory = (PreferenceCategory) ensureFindPreference("debug_category");
+    statusScreen.removePreference(debugCategory);
+  }
+
+  /**
+   * A Runnable that persists engine selections to shared prefs, and then
+   * requests a delayed sync.
+   * <p>
+   * References the member <code>fxAccount</code> and is specific to the Android
+   * account associated to that account.
+   */
+  protected class PersistEngineSelectionsRunnable implements Runnable {
+    private final Map<String, Boolean> engineSelections;
+
+    protected PersistEngineSelectionsRunnable(Map<String, Boolean> engineSelections) {
+      this.engineSelections = engineSelections;
+    }
+
+    @Override
+    public void run() {
+      try {
+        // Name shadowing -- do you like it, or do you love it?
+        AndroidFxAccount fxAccount = FxAccountStatusFragment.this.fxAccount;
+        if (fxAccount == null) {
+          return;
+        }
+        Logger.info(LOG_TAG, "Persisting engine selections: " + engineSelections.toString());
+        SyncConfiguration.storeSelectedEnginesToPrefs(fxAccount.getSyncPrefs(), engineSelections);
+        requestDelayedSync();
+      } catch (Exception e) {
+        Logger.warn(LOG_TAG, "Got exception persisting selected engines; ignoring.", e);
+        return;
+      }
+    }
+  }
+
+  /**
+   * A Runnable that requests a sync.
+   * <p>
+   * References the member <code>fxAccount</code>, but is not specific to the
+   * Android account associated to that account.
+   */
+  protected class RequestSyncRunnable implements Runnable {
+    @Override
+    public void run() {
+      // Name shadowing -- do you like it, or do you love it?
+      AndroidFxAccount fxAccount = FxAccountStatusFragment.this.fxAccount;
+      if (fxAccount == null) {
+        return;
+      }
+      Logger.info(LOG_TAG, "Requesting a sync sometime soon.");
+      fxAccount.requestEventualSync(null, null);
+    }
+  }
+
+  /**
+   * The Runnable that schedules a future update and updates the last synced time.
+   */
+  protected class LastSyncTimeUpdateRunnable implements Runnable  {
+    @Override
+    public void run() {
+      scheduleAndUpdateLastSyncedTime();
+    }
+  }
+
+  /**
+   * Broadcast receiver to receive updates for the cached profile action.
+   */
+  public class FxAccountProfileInformationReceiver extends BroadcastReceiver {
+    @Override
+    public void onReceive(Context context, Intent intent) {
+      if (!intent.getAction().equals(FxAccountConstants.ACCOUNT_PROFILE_JSON_UPDATED_ACTION)) {
+        return;
+      }
+
+      Logger.info(LOG_TAG, "Profile avatar cache update action broadcast received.");
+      // Update the UI from cached profile json on the main thread.
+      getActivity().runOnUiThread(new Runnable() {
+        @Override
+        public void run() {
+          updateProfileInformation();
+        }
+      });
+    }
+  }
+
+  /**
+   * A separate listener to separate debug logic from main code paths.
+   */
+  protected class DebugPreferenceClickListener implements OnPreferenceClickListener {
+    @Override
+    public boolean onPreferenceClick(Preference preference) {
+      final String key = preference.getKey();
+      if ("debug_refresh".equals(key)) {
+        Logger.info(LOG_TAG, "Refreshing.");
+        refresh();
+      } else if ("debug_dump".equals(key)) {
+        fxAccount.dump();
+      } else if ("debug_force_sync".equals(key)) {
+        Logger.info(LOG_TAG, "Force syncing.");
+        fxAccount.requestImmediateSync(null, null);
+        // No sense refreshing, since the sync will complete in the future.
+      } else if ("debug_forget_certificate".equals(key)) {
+        State state = fxAccount.getState();
+        try {
+          Married married = (Married) state;
+          Logger.info(LOG_TAG, "Moving to Cohabiting state: Forgetting certificate.");
+          fxAccount.setState(married.makeCohabitingState());
+          refresh();
+        } catch (ClassCastException e) {
+          Logger.info(LOG_TAG, "Not in Married state; can't forget certificate.");
+          // Ignore.
+        }
+      } else if ("debug_invalidate_certificate".equals(key)) {
+        State state = fxAccount.getState();
+        try {
+          Married married = (Married) state;
+          Logger.info(LOG_TAG, "Invalidating certificate.");
+          fxAccount.setState(married.makeCohabitingState().withCertificate("INVALID CERTIFICATE"));
+          refresh();
+        } catch (ClassCastException e) {
+          Logger.info(LOG_TAG, "Not in Married state; can't invalidate certificate.");
+          // Ignore.
+        }
+      } else if ("debug_require_password".equals(key)) {
+        Logger.info(LOG_TAG, "Moving to Separated state: Forgetting password.");
+        State state = fxAccount.getState();
+        fxAccount.setState(state.makeSeparatedState());
+        refresh();
+      } else if ("debug_require_upgrade".equals(key)) {
+        Logger.info(LOG_TAG, "Moving to Doghouse state: Requiring upgrade.");
+        State state = fxAccount.getState();
+        fxAccount.setState(state.makeDoghouseState());
+        refresh();
+      } else if ("debug_migrated_from_sync11".equals(key)) {
+        Logger.info(LOG_TAG, "Moving to MigratedFromSync11 state: Requiring password.");
+        State state = fxAccount.getState();
+        fxAccount.setState(state.makeMigratedFromSync11State(null));
+        refresh();
+      } else if ("debug_make_account_stage".equals(key)) {
+        Logger.info(LOG_TAG, "Moving Account endpoints, in place, to stage.  Deleting Sync and RL prefs and requiring password.");
+        fxAccount.unsafeTransitionToStageEndpoints();
+        refresh();
+      } else if ("debug_make_account_default".equals(key)) {
+        Logger.info(LOG_TAG, "Moving Account endpoints, in place, to default (production).  Deleting Sync and RL prefs and requiring password.");
+        fxAccount.unsafeTransitionToDefaultEndpoints();
+        refresh();
+      } else {
+        return false;
+      }
+      return true;
+    }
+  }
+
+  /**
+   * Iterate through debug buttons, adding a special debug preference click
+   * listener to each of them.
+   */
+  protected void connectDebugButtons() {
+    // Separate listener to really separate debug logic from main code paths.
+    final OnPreferenceClickListener listener = new DebugPreferenceClickListener();
+
+    // We don't want to use Android resource strings for debug UI, so we just
+    // use the keys throughout.
+    final PreferenceCategory debugCategory = (PreferenceCategory) ensureFindPreference("debug_category");
+    debugCategory.setTitle(debugCategory.getKey());
+
+    for (int i = 0; i < debugCategory.getPreferenceCount(); i++) {
+      final Preference button = debugCategory.getPreference(i);
+      button.setTitle(button.getKey()); // Not very friendly, but this is for debugging only!
+      button.setOnPreferenceClickListener(listener);
+    }
+  }
+
+  @Override
+  public boolean onPreferenceChange(Preference preference, Object newValue) {
+    if (preference == deviceNamePreference) {
+      String newClientName = (String) newValue;
+      if (TextUtils.isEmpty(newClientName)) {
+        newClientName = clientsDataDelegate.getDefaultClientName();
+      }
+      final long now = System.currentTimeMillis();
+      clientsDataDelegate.setClientName(newClientName, now);
+      // Force sync the client record, we want the user to see the device name change immediately
+      // on the FxA Device Manager if possible ( = we are online) to avoid confusion
+      // ("I changed my Android's device name but I don't see it on my computer").
+      fxAccount.requestImmediateSync(STAGES_TO_SYNC_ON_DEVICE_NAME_CHANGE, null);
+      hardRefresh(); // Updates the value displayed to the user, among other things.
+      return true;
+    }
+
+    // For everything else, accept the change.
+    return true;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountUpdateCredentialsActivityWeb.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountUpdateCredentialsActivityWeb.java
new file mode 100644
index 000000000..5a2ea79c8
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountUpdateCredentialsActivityWeb.java
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+public class FxAccountUpdateCredentialsActivityWeb extends FxAccountWebFlowActivity {
+  public FxAccountUpdateCredentialsActivityWeb() {
+    super(CANNOT_RESUME_WHEN_NO_ACCOUNTS_EXIST, "force_auth");
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountWebFlowActivity.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountWebFlowActivity.java
new file mode 100644
index 000000000..e33e9c577
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/FxAccountWebFlowActivity.java
@@ -0,0 +1,91 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+import android.content.Intent;
+import android.os.Bundle;
+import org.mozilla.gecko.Locales;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.sync.setup.activities.ActivityUtils;
+
+/**
+ * Activity which shows the status activity or passes through to web flow.
+ */
+public abstract class FxAccountWebFlowActivity extends FxAccountAbstractActivity {
+    protected static final String LOG_TAG = FxAccountWebFlowActivity.class.getSimpleName();
+
+    protected static final String ABOUT_ACCOUNTS = "about:accounts";
+
+    public static final String EXTRA_ENDPOINT = "entrypoint";
+
+    protected static final String[] EXTRAS_TO_PASSTHROUGH = new String[] {
+            EXTRA_ENDPOINT,
+    };
+
+    private final String action;
+    private final String extras;
+
+    public FxAccountWebFlowActivity(int resume, String action) {
+        this(resume, action, null);
+    }
+
+    public FxAccountWebFlowActivity(int resume, String action, String extras) {
+        super(resume);
+        this.action = action;
+        this.extras = (extras != null) ? ("&" + extras) : "";
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void onCreate(Bundle icicle) {
+        Logger.setThreadLogTag(FxAccountConstants.GLOBAL_LOG_TAG);
+        Logger.debug(LOG_TAG, "onCreate(" + icicle + ")");
+
+        Locales.initializeLocale(getApplicationContext());
+
+        super.onCreate(icicle);
+    }
+
+    protected boolean redirectIfAppropriate() {
+        final boolean redirected = super.redirectIfAppropriate();
+        if (redirected) {
+            return true;
+        }
+
+        final StringBuilder sb = new StringBuilder();
+        sb.append(ABOUT_ACCOUNTS);
+        sb.append("?action=");
+        sb.append(action);
+        sb.append(extras);
+
+        // Pass through a set of known string values from intent extras to about:accounts.
+        final Intent intent = getIntent();
+        if (intent != null) {
+            for (String key : EXTRAS_TO_PASSTHROUGH) {
+                final String value = intent.getStringExtra(key);
+                if (value != null) {
+                    sb.append("&");
+                    sb.append(key);
+                    sb.append("=");
+                    sb.append(value);
+                }
+            }
+        }
+
+        ActivityUtils.openURLInFennec(getApplicationContext(), sb.toString());
+        return true;
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+
+        // We are always redirected.
+        this.finish();
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/PicassoPreferenceIconTarget.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/PicassoPreferenceIconTarget.java
new file mode 100644
index 000000000..f71d3ed1c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/activities/PicassoPreferenceIconTarget.java
@@ -0,0 +1,63 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.activities;
+
+import android.content.res.Resources;
+import android.graphics.Bitmap;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
+import android.preference.Preference;
+import android.support.v4.graphics.drawable.RoundedBitmapDrawable;
+import android.support.v4.graphics.drawable.RoundedBitmapDrawableFactory;
+import com.squareup.picasso.Picasso;
+import com.squareup.picasso.Target;
+import org.mozilla.gecko.AppConstants;
+
+/**
+ * A Picasso Target that updates a preference icon.
+ *
+ * Nota bene: Android grew support for updating preference icons programatically
+ * only in API 11.  This class silently ignores requests before API 11.
+ */
+public class PicassoPreferenceIconTarget implements Target {
+    private final Preference preference;
+    private final Resources resources;
+    private final float cornerRadius;
+
+    public PicassoPreferenceIconTarget(Resources resources, Preference preference) {
+        this(resources, preference, 0);
+    }
+
+    public PicassoPreferenceIconTarget(Resources resources, Preference preference, float cornerRadius) {
+        this.resources = resources;
+        this.preference = preference;
+        this.cornerRadius = cornerRadius;
+    }
+
+    @Override
+    public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
+        final Drawable drawable;
+        if (cornerRadius > 0) {
+            final RoundedBitmapDrawable roundedBitmapDrawable;
+            roundedBitmapDrawable = RoundedBitmapDrawableFactory.create(resources, bitmap);
+            roundedBitmapDrawable.setCornerRadius(cornerRadius);
+            roundedBitmapDrawable.setAntiAlias(true);
+            drawable = roundedBitmapDrawable;
+        } else {
+            drawable = new BitmapDrawable(resources, bitmap);
+        }
+        preference.setIcon(drawable);
+    }
+
+    @Override
+    public void onBitmapFailed(Drawable errorDrawable) {
+        preference.setIcon(errorDrawable);
+    }
+
+    @Override
+    public void onPrepareLoad(Drawable placeHolderDrawable) {
+        preference.setIcon(placeHolderDrawable);
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/AccountPickler.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/AccountPickler.java
new file mode 100644
index 000000000..3f2c5620d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/AccountPickler.java
@@ -0,0 +1,362 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.authenticator;
+
+import java.io.FileOutputStream;
+import java.io.PrintStream;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.fxa.login.State.StateLabel;
+import org.mozilla.gecko.fxa.login.StateFactory;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+import org.mozilla.gecko.sync.Utils;
+
+import android.content.Context;
+
+/**
+ * Android deletes Account objects when the Authenticator that owns the Account
+ * disappears. This happens when an App is installed to the SD card and the SD
+ * card is un-mounted or the device is rebooted.
+ * <p>
+ * We work around this by pickling the current Firefox account data every sync
+ * and unpickling when we check if Firefox accounts exist (called from Fennec).
+ * <p>
+ * Android just doesn't support installing Apps that define long-lived Services
+ * and/or own Account types onto the SD card. The documentation says not to do
+ * it. There are hordes of developers who want to do it, and have tried to
+ * register for almost every "package installation changed" broadcast intent
+ * that Android supports. They all explicitly state that the package that has
+ * changed does *not* receive the broadcast intent, thereby preventing an App
+ * from re-establishing its state.
+ * <p>
+ * <a href="http://developer.android.com/guide/topics/data/install-location.html">Reference.</a>
+ * <p>
+ * <b>Quote</b>: Your AbstractThreadedSyncAdapter and all its sync functionality
+ * will not work until external storage is remounted.
+ * <p>
+ * <b>Quote</b>: Your running Service will be killed and will not be restarted
+ * when external storage is remounted. You can, however, register for the
+ * ACTION_EXTERNAL_APPLICATIONS_AVAILABLE broadcast Intent, which will notify
+ * your application when applications installed on external storage have become
+ * available to the system again. At which time, you can restart your Service.
+ * <p>
+ * Problem: <a href="http://code.google.com/p/android/issues/detail?id=8485">that intent doesn't work</a>!
+ * <p>
+ * See bug 768102 for more information in the context of Sync.
+ */
+public class AccountPickler {
+  public static final String LOG_TAG = AccountPickler.class.getSimpleName();
+
+  public static final long PICKLE_VERSION = 3;
+
+  public static final String KEY_PICKLE_VERSION = "pickle_version";
+  public static final String KEY_PICKLE_TIMESTAMP = "pickle_timestamp";
+
+  public static final String KEY_ACCOUNT_VERSION = "account_version";
+  public static final String KEY_ACCOUNT_TYPE = "account_type";
+  public static final String KEY_EMAIL = "email";
+  public static final String KEY_PROFILE = "profile";
+  public static final String KEY_IDP_SERVER_URI = "idpServerURI";
+  public static final String KEY_TOKEN_SERVER_URI = "tokenServerURI";
+  public static final String KEY_PROFILE_SERVER_URI = "profileServerURI";
+
+  public static final String KEY_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP = "authoritiesToSyncAutomaticallyMap";
+
+  // Deprecated, but maintained for migration purposes.
+  public static final String KEY_IS_SYNCING_ENABLED = "isSyncingEnabled";
+
+  public static final String KEY_BUNDLE = "bundle";
+
+  /**
+   * Remove Firefox account persisted to disk.
+   * This operation is synchronized to avoid race condition while deleting the account.
+   *
+   * @param context Android context.
+   * @param filename name of persisted pickle file; must not contain path separators.
+   * @return <code>true</code> if given pickle existed and was successfully deleted.
+   */
+  public synchronized static boolean deletePickle(final Context context, final String filename) {
+    return context.deleteFile(filename);
+  }
+
+  public static ExtendedJSONObject toJSON(final AndroidFxAccount account, final long now) {
+    final ExtendedJSONObject o = new ExtendedJSONObject();
+    o.put(KEY_PICKLE_VERSION, PICKLE_VERSION);
+    o.put(KEY_PICKLE_TIMESTAMP, now);
+
+    o.put(KEY_ACCOUNT_VERSION, AndroidFxAccount.CURRENT_ACCOUNT_VERSION);
+    o.put(KEY_ACCOUNT_TYPE, FxAccountConstants.ACCOUNT_TYPE);
+    o.put(KEY_EMAIL, account.getEmail());
+    o.put(KEY_PROFILE, account.getProfile());
+    o.put(KEY_IDP_SERVER_URI, account.getAccountServerURI());
+    o.put(KEY_TOKEN_SERVER_URI, account.getTokenServerURI());
+    o.put(KEY_PROFILE_SERVER_URI, account.getProfileServerURI());
+
+    final ExtendedJSONObject p = new ExtendedJSONObject();
+    for (Entry<String, Boolean> pair : account.getAuthoritiesToSyncAutomaticallyMap().entrySet()) {
+      p.put(pair.getKey(), pair.getValue());
+    }
+    o.put(KEY_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP, p);
+
+    // TODO: If prefs version changes under us, SyncPrefsPath will change, "clearing" prefs.
+
+    final ExtendedJSONObject bundle = account.unbundle();
+    if (bundle == null) {
+      Logger.warn(LOG_TAG, "Unable to obtain account bundle; aborting.");
+      return null;
+    }
+    o.put(KEY_BUNDLE, bundle);
+
+    return o;
+  }
+
+  /**
+   * Persist Firefox account to disk as a JSON object.
+   * This operation is synchronized to avoid race condition while deleting the account.
+   *
+   * @param account the AndroidFxAccount to persist to disk
+   * @param filename name of file to persist to; must not contain path separators.
+   */
+  public synchronized static void pickle(final AndroidFxAccount account, final String filename) {
+    final ExtendedJSONObject o = toJSON(account, System.currentTimeMillis());
+    writeToDisk(account.context, filename, o);
+  }
+
+  private static void writeToDisk(final Context context, final String filename,
+      final ExtendedJSONObject pickle) {
+    try {
+      final FileOutputStream fos = context.openFileOutput(filename, Context.MODE_PRIVATE);
+      try {
+        final PrintStream ps = new PrintStream(fos);
+        try {
+          ps.print(pickle.toJSONString());
+          Logger.debug(LOG_TAG, "Persisted " + pickle.keySet().size() +
+              " account settings to " + filename + ".");
+        } finally {
+          ps.close();
+        }
+      } finally {
+        fos.close();
+      }
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Caught exception persisting account settings to " + filename +
+          "; ignoring.", e);
+    }
+  }
+
+  /**
+   * Create Android account from saved JSON object. Assumes that an account does not exist.
+   * This operation is synchronized to avoid race condition while deleting the account.
+   *
+   * @param context
+   *          Android context.
+   * @param filename
+   *          name of file to read from; must not contain path separators.
+   * @return created Android account, or null on error.
+   */
+  public synchronized static AndroidFxAccount unpickle(final Context context, final String filename) {
+    final String jsonString = Utils.readFile(context, filename);
+    if (jsonString == null) {
+      Logger.info(LOG_TAG, "Pickle file '" + filename + "' not found; aborting.");
+      return null;
+    }
+
+    ExtendedJSONObject json = null;
+    try {
+      json = new ExtendedJSONObject(jsonString);
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception reading pickle file '" + filename + "'; aborting.", e);
+      return null;
+    }
+
+    final UnpickleParams params;
+    try {
+      params = UnpickleParams.fromJSON(json);
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception extracting unpickle json; aborting.", e);
+      return null;
+    }
+
+    final AndroidFxAccount account;
+    try {
+      account = AndroidFxAccount.addAndroidAccount(context, params.email, params.profile,
+          params.authServerURI, params.tokenServerURI, params.profileServerURI, params.state,
+          params.authoritiesToSyncAutomaticallyMap,
+          params.accountVersion,
+          true, params.bundle);
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Exception when adding Android Account; aborting.", e);
+      return null;
+    }
+
+    if (account == null) {
+      Logger.warn(LOG_TAG, "Failed to add Android Account; aborting.");
+      return null;
+    }
+
+    Long timestamp = json.getLong(KEY_PICKLE_TIMESTAMP);
+    if (timestamp == null) {
+      Logger.warn(LOG_TAG, "Did not find timestamp in pickle file; ignoring.");
+      timestamp = -1L;
+    }
+
+    Logger.info(LOG_TAG, "Un-pickled Android account named " + params.email + " (version " +
+        params.pickleVersion + ", pickled at " + timestamp + ").");
+
+    return account;
+  }
+
+  private static class UnpickleParams {
+    private Long pickleVersion;
+
+    private int accountVersion;
+    private String email;
+    private String profile;
+    private String authServerURI;
+    private String tokenServerURI;
+    private String profileServerURI;
+    private final Map<String, Boolean> authoritiesToSyncAutomaticallyMap = new HashMap<>();
+
+    private ExtendedJSONObject bundle;
+    private State state;
+
+    private UnpickleParams() {
+    }
+
+    private static UnpickleParams fromJSON(final ExtendedJSONObject json)
+        throws InvalidKeySpecException, NoSuchAlgorithmException, NonObjectJSONException {
+      final UnpickleParams params = new UnpickleParams();
+      params.pickleVersion = json.getLong(KEY_PICKLE_VERSION);
+      if (params.pickleVersion == null) {
+        throw new IllegalStateException("Pickle version not found.");
+      }
+
+      /*
+       * Version 1 and version 2 are identical, except version 2 throws if the
+       * internal Android Account type has changed. Version 1 used to throw in
+       * this case, but we intentionally used the pickle file to migrate across
+       * Account types, bumping the version simultaneously.
+       *
+       * Version 3 replaces "isSyncEnabled" with a map (String -> Boolean)
+       * associating Android authorities to whether or not they are configured
+       * to sync automatically.
+       */
+      switch (params.pickleVersion.intValue()) {
+      case 3: {
+        // Sanity check.
+        final String accountType = json.getString(KEY_ACCOUNT_TYPE);
+        if (!FxAccountConstants.ACCOUNT_TYPE.equals(accountType)) {
+          throw new IllegalStateException("Account type has changed from " + accountType + " to " + FxAccountConstants.ACCOUNT_TYPE + ".");
+        }
+
+        params.unpickleV3(json);
+      }
+      break;
+
+      case 2: {
+        // Sanity check.
+        final String accountType = json.getString(KEY_ACCOUNT_TYPE);
+        if (!FxAccountConstants.ACCOUNT_TYPE.equals(accountType)) {
+          throw new IllegalStateException("Account type has changed from " + accountType + " to " + FxAccountConstants.ACCOUNT_TYPE + ".");
+        }
+
+        params.unpickleV1(json);
+      }
+      break;
+
+      case 1: {
+        // Warn about account type changing, but don't throw over it.
+        final String accountType = json.getString(KEY_ACCOUNT_TYPE);
+        if (!FxAccountConstants.ACCOUNT_TYPE.equals(accountType)) {
+          Logger.warn(LOG_TAG, "Account type has changed from " + accountType + " to " + FxAccountConstants.ACCOUNT_TYPE + "; ignoring.");
+        }
+
+        params.unpickleV1(json);
+      }
+      break;
+
+      default:
+        throw new IllegalStateException("Unknown pickle version, " + params.pickleVersion + ".");
+      }
+
+      return params;
+    }
+
+    private void unpickleV1(final ExtendedJSONObject json)
+        throws NonObjectJSONException, NoSuchAlgorithmException, InvalidKeySpecException {
+
+      this.accountVersion = json.getIntegerSafely(KEY_ACCOUNT_VERSION);
+      this.email = json.getString(KEY_EMAIL);
+      this.profile = json.getString(KEY_PROFILE);
+      this.authServerURI = json.getString(KEY_IDP_SERVER_URI);
+      this.tokenServerURI = json.getString(KEY_TOKEN_SERVER_URI);
+      this.profileServerURI = json.getString(KEY_PROFILE_SERVER_URI);
+
+      // Fallback to default value when profile server URI was not pickled.
+      if (this.profileServerURI == null) {
+        this.profileServerURI = FxAccountConstants.DEFAULT_AUTH_SERVER_ENDPOINT.equals(this.authServerURI)
+            ? FxAccountConstants.DEFAULT_PROFILE_SERVER_ENDPOINT
+            : FxAccountConstants.STAGE_PROFILE_SERVER_ENDPOINT;
+      }
+
+      // We get the default value for everything except syncing browser data.
+      this.authoritiesToSyncAutomaticallyMap.put(BrowserContract.AUTHORITY, json.getBoolean(KEY_IS_SYNCING_ENABLED));
+
+      this.bundle = json.getObject(KEY_BUNDLE);
+      if (bundle == null) {
+        throw new IllegalStateException("Pickle bundle is null.");
+      }
+      this.state = getState(bundle);
+    }
+
+    private void unpickleV3(final ExtendedJSONObject json)
+        throws NonObjectJSONException, NoSuchAlgorithmException, InvalidKeySpecException {
+      // We'll overwrite the extracted sync automatically map.
+      unpickleV1(json);
+
+      // Extract the map of authorities to sync automatically.
+      authoritiesToSyncAutomaticallyMap.clear();
+      final ExtendedJSONObject o = json.getObject(KEY_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP);
+      if (o == null) {
+        return;
+      }
+      for (String key : o.keySet()) {
+        final Boolean enabled = o.getBoolean(key);
+        if (enabled != null) {
+          authoritiesToSyncAutomaticallyMap.put(key, enabled);
+        }
+      }
+    }
+
+    private State getState(final ExtendedJSONObject bundle) throws InvalidKeySpecException,
+            NonObjectJSONException, NoSuchAlgorithmException {
+      // TODO: Should copy-pasta BUNDLE_KEY_STATE & LABEL to this file to ensure we maintain
+      // old versions?
+      final StateLabel stateLabelString = StateLabel.valueOf(
+          bundle.getString(AndroidFxAccount.BUNDLE_KEY_STATE_LABEL));
+      final String stateString = bundle.getString(AndroidFxAccount.BUNDLE_KEY_STATE);
+      if (stateLabelString == null || stateString == null) {
+        throw new IllegalStateException("stateLabel and stateString must not be null, but: " +
+            "(stateLabel == null) = " + (stateLabelString == null) +
+            " and (stateString == null) = " + (stateString == null));
+      }
+
+      try {
+        return StateFactory.fromJSONObject(stateLabelString, new ExtendedJSONObject(stateString));
+      } catch (Exception e) {
+        throw new IllegalStateException("could not get state", e);
+      }
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/AndroidFxAccount.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/AndroidFxAccount.java
new file mode 100644
index 000000000..d7ce7c47f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/AndroidFxAccount.java
@@ -0,0 +1,929 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.authenticator;
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.annotation.SuppressLint;
+import android.app.Activity;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.ResultReceiver;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.v4.content.LocalBroadcastManager;
+import android.text.TextUtils;
+import android.util.Log;
+
+import org.mozilla.gecko.background.common.GlobalConstants;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.fxa.FirefoxAccounts;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.fxa.login.State.StateLabel;
+import org.mozilla.gecko.fxa.login.StateFactory;
+import org.mozilla.gecko.fxa.login.TokensAndKeysState;
+import org.mozilla.gecko.fxa.sync.FxAccountProfileService;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.setup.Constants;
+import org.mozilla.gecko.util.ThreadUtils;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URISyntaxException;
+import java.security.GeneralSecurityException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Semaphore;
+
+/**
+ * A Firefox Account that stores its details and state as user data attached to
+ * an Android Account instance.
+ * <p>
+ * Account user data is accessible only to the Android App(s) that own the
+ * Account type. Account user data is not removed when the App's private data is
+ * cleared.
+ */
+public class AndroidFxAccount {
+  protected static final String LOG_TAG = AndroidFxAccount.class.getSimpleName();
+
+  public static final int CURRENT_SYNC_PREFS_VERSION = 1;
+  public static final int CURRENT_RL_PREFS_VERSION = 1;
+
+  // When updating the account, do not forget to update AccountPickler.
+  public static final int CURRENT_ACCOUNT_VERSION = 3;
+  public static final String ACCOUNT_KEY_ACCOUNT_VERSION = "version";
+  public static final String ACCOUNT_KEY_PROFILE = "profile";
+  public static final String ACCOUNT_KEY_IDP_SERVER = "idpServerURI";
+  private static final String ACCOUNT_KEY_PROFILE_SERVER = "profileServerURI";
+
+  public static final String ACCOUNT_KEY_TOKEN_SERVER = "tokenServerURI";       // Sync-specific.
+  public static final String ACCOUNT_KEY_DESCRIPTOR = "descriptor";
+
+  public static final int CURRENT_BUNDLE_VERSION = 2;
+  public static final String BUNDLE_KEY_BUNDLE_VERSION = "version";
+  public static final String BUNDLE_KEY_STATE_LABEL = "stateLabel";
+  public static final String BUNDLE_KEY_STATE = "state";
+  public static final String BUNDLE_KEY_PROFILE_JSON = "profile";
+
+  public static final String ACCOUNT_KEY_DEVICE_ID = "deviceId";
+  public static final String ACCOUNT_KEY_DEVICE_REGISTRATION_VERSION = "deviceRegistrationVersion";
+
+  // Account authentication token type for fetching account profile.
+  public static final String PROFILE_OAUTH_TOKEN_TYPE = "oauth::profile";
+
+  // Services may request OAuth tokens from the Firefox Account dynamically.
+  // Each such token is prefixed with "oauth::" and a service-dependent scope.
+  // Such tokens should be destroyed when the account is removed from the device.
+  // This list collects all the known "oauth::" token types in order to delete them when necessary.
+  private static final List<String> KNOWN_OAUTH_TOKEN_TYPES;
+
+  static {
+    final List<String> list = new ArrayList<>();
+    list.add(PROFILE_OAUTH_TOKEN_TYPE);
+    KNOWN_OAUTH_TOKEN_TYPES = Collections.unmodifiableList(list);
+  }
+
+  public static final Map<String, Boolean> DEFAULT_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP;
+  static {
+    final HashMap<String, Boolean> m = new HashMap<String, Boolean>();
+    // By default, Firefox Sync is enabled.
+    m.put(BrowserContract.AUTHORITY, true);
+    DEFAULT_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP = Collections.unmodifiableMap(m);
+  }
+
+  private static final String PREF_KEY_LAST_SYNCED_TIMESTAMP = "lastSyncedTimestamp";
+
+  protected final Context context;
+  protected final AccountManager accountManager;
+  protected final Account account;
+
+  /**
+   * A cache associating Account name (email address) to a representation of the
+   * account's internal bundle.
+   * <p>
+   * The cache is invalidated entirely when <it>any</it> new Account is added,
+   * because there is no reliable way to know that an Account has been removed
+   * and then re-added.
+   */
+  protected static final ConcurrentHashMap<String, ExtendedJSONObject> perAccountBundleCache =
+      new ConcurrentHashMap<>();
+
+  public static void invalidateCaches() {
+    perAccountBundleCache.clear();
+  }
+
+  /**
+   * Create an Android Firefox Account instance backed by an Android Account
+   * instance.
+   * <p>
+   * We expect a long-lived application context to avoid life-cycle issues that
+   * might arise if the internally cached AccountManager instance surfaces UI.
+   * <p>
+   * We take care to not install any listeners or observers that might outlive
+   * the AccountManager; and Android ensures the AccountManager doesn't outlive
+   * the associated context.
+   *
+   * @param applicationContext
+   *          to use as long-lived ambient Android context.
+   * @param account
+   *          Android account to use for storage.
+   */
+  public AndroidFxAccount(Context applicationContext, Account account) {
+    this.context = applicationContext;
+    this.account = account;
+    this.accountManager = AccountManager.get(this.context);
+  }
+
+  public static AndroidFxAccount fromContext(Context context) {
+    context = context.getApplicationContext();
+    Account account = FirefoxAccounts.getFirefoxAccount(context);
+    if (account == null) {
+      return null;
+    }
+    return new AndroidFxAccount(context, account);
+  }
+
+  /**
+   * Persist the Firefox account to disk as a JSON object. Note that this is a wrapper around
+   * {@link AccountPickler#pickle}, and is identical to calling it directly.
+   * <p>
+   * Note that pickling is different from bundling, which involves operations on a
+   * {@link android.os.Bundle Bundle} object of miscellaneous data associated with the account.
+   * See {@link #persistBundle} and {@link #unbundle} for more.
+   */
+  public void pickle(final String filename) {
+    AccountPickler.pickle(this, filename);
+  }
+
+  public Account getAndroidAccount() {
+    return this.account;
+  }
+
+  protected int getAccountVersion() {
+    String v = accountManager.getUserData(account, ACCOUNT_KEY_ACCOUNT_VERSION);
+    if (v == null) {
+      return 0;         // Implicit.
+    }
+
+    try {
+      return Integer.parseInt(v, 10);
+    } catch (NumberFormatException ex) {
+      return 0;
+    }
+  }
+
+  /**
+   * Saves the given data as the internal bundle associated with this account.
+   * @param bundle to write to account.
+   */
+  protected synchronized void persistBundle(ExtendedJSONObject bundle) {
+    perAccountBundleCache.put(account.name, bundle);
+    accountManager.setUserData(account, ACCOUNT_KEY_DESCRIPTOR, bundle.toJSONString());
+  }
+
+  protected ExtendedJSONObject unbundle() {
+    return unbundle(true);
+  }
+
+  /**
+   * Retrieve the internal bundle associated with this account.
+   * @return bundle associated with account.
+   */
+  protected synchronized ExtendedJSONObject unbundle(boolean allowCachedBundle) {
+    if (allowCachedBundle) {
+      final ExtendedJSONObject cachedBundle = perAccountBundleCache.get(account.name);
+      if (cachedBundle != null) {
+        Logger.debug(LOG_TAG, "Returning cached account bundle.");
+        return cachedBundle;
+      }
+    }
+
+    final int version = getAccountVersion();
+    if (version < CURRENT_ACCOUNT_VERSION) {
+      // Needs upgrade. For now, do nothing. We'd like to just put your account
+      // into the Separated state here and have you update your credentials.
+      return null;
+    }
+
+    if (version > CURRENT_ACCOUNT_VERSION) {
+      // Oh dear.
+      return null;
+    }
+
+    String bundleString = accountManager.getUserData(account, ACCOUNT_KEY_DESCRIPTOR);
+    if (bundleString == null) {
+      return null;
+    }
+    final ExtendedJSONObject bundle = unbundleAccountV2(bundleString);
+    perAccountBundleCache.put(account.name, bundle);
+    Logger.info(LOG_TAG, "Account bundle persisted to cache.");
+    return bundle;
+  }
+
+  protected String getBundleData(String key) {
+    ExtendedJSONObject o = unbundle();
+    if (o == null) {
+      return null;
+    }
+    return o.getString(key);
+  }
+
+  protected boolean getBundleDataBoolean(String key, boolean def) {
+    ExtendedJSONObject o = unbundle();
+    if (o == null) {
+      return def;
+    }
+    Boolean b = o.getBoolean(key);
+    if (b == null) {
+      return def;
+    }
+    return b;
+  }
+
+  protected byte[] getBundleDataBytes(String key) {
+    ExtendedJSONObject o = unbundle();
+    if (o == null) {
+      return null;
+    }
+    return o.getByteArrayHex(key);
+  }
+
+  protected void updateBundleValues(String key, String value, String... more) {
+    if (more.length % 2 != 0) {
+      throw new IllegalArgumentException("more must be a list of key, value pairs");
+    }
+    ExtendedJSONObject descriptor = unbundle();
+    if (descriptor == null) {
+      return;
+    }
+    descriptor.put(key, value);
+    for (int i = 0; i + 1 < more.length; i += 2) {
+      descriptor.put(more[i], more[i+1]);
+    }
+    persistBundle(descriptor);
+  }
+
+  private ExtendedJSONObject unbundleAccountV1(String bundle) {
+    ExtendedJSONObject o;
+    try {
+      o = new ExtendedJSONObject(bundle);
+    } catch (Exception e) {
+      return null;
+    }
+    if (CURRENT_BUNDLE_VERSION == o.getIntegerSafely(BUNDLE_KEY_BUNDLE_VERSION)) {
+      return o;
+    }
+    return null;
+  }
+
+  private ExtendedJSONObject unbundleAccountV2(String bundle) {
+    return unbundleAccountV1(bundle);
+  }
+
+  /**
+   * Note that if the user clears data, an account will be left pointing to a
+   * deleted profile. Such is life.
+   */
+  public String getProfile() {
+    return accountManager.getUserData(account, ACCOUNT_KEY_PROFILE);
+  }
+
+  public String getAccountServerURI() {
+    return accountManager.getUserData(account, ACCOUNT_KEY_IDP_SERVER);
+  }
+
+  public String getTokenServerURI() {
+    return accountManager.getUserData(account, ACCOUNT_KEY_TOKEN_SERVER);
+  }
+
+  public String getProfileServerURI() {
+    String profileURI = accountManager.getUserData(account, ACCOUNT_KEY_PROFILE_SERVER);
+    if (profileURI == null) {
+      if (isStaging()) {
+        return FxAccountConstants.STAGE_PROFILE_SERVER_ENDPOINT;
+      }
+      return FxAccountConstants.DEFAULT_PROFILE_SERVER_ENDPOINT;
+    }
+    return profileURI;
+  }
+
+  public String getOAuthServerURI() {
+    // Allow testing against stage.
+    if (isStaging()) {
+      return FxAccountConstants.STAGE_OAUTH_SERVER_ENDPOINT;
+    } else {
+      return FxAccountConstants.DEFAULT_OAUTH_SERVER_ENDPOINT;
+    }
+  }
+
+  private boolean isStaging() {
+    return FxAccountConstants.STAGE_AUTH_SERVER_ENDPOINT.equals(getAccountServerURI());
+  }
+
+  private String constructPrefsPath(String product, long version, String extra) throws GeneralSecurityException, UnsupportedEncodingException {
+    String profile = getProfile();
+    String username = account.name;
+
+    if (profile == null) {
+      throw new IllegalStateException("Missing profile. Cannot fetch prefs.");
+    }
+
+    if (username == null) {
+      throw new IllegalStateException("Missing username. Cannot fetch prefs.");
+    }
+
+    final String fxaServerURI = getAccountServerURI();
+    if (fxaServerURI == null) {
+      throw new IllegalStateException("No account server URI. Cannot fetch prefs.");
+    }
+
+    // This is unique for each syncing 'view' of the account.
+    final String serverURLThing = fxaServerURI + "!" + extra;
+    return Utils.getPrefsPath(product, username, serverURLThing, profile, version);
+  }
+
+  /**
+   * This needs to return a string because of the tortured prefs access in GlobalSession.
+   */
+  public String getSyncPrefsPath() throws GeneralSecurityException, UnsupportedEncodingException {
+    final String tokenServerURI = getTokenServerURI();
+    if (tokenServerURI == null) {
+      throw new IllegalStateException("No token server URI. Cannot fetch prefs.");
+    }
+
+    final String product = GlobalConstants.BROWSER_INTENT_PACKAGE + ".fxa";
+    final long version = CURRENT_SYNC_PREFS_VERSION;
+    return constructPrefsPath(product, version, tokenServerURI);
+  }
+
+  public String getReadingListPrefsPath() throws GeneralSecurityException, UnsupportedEncodingException {
+    final String product = GlobalConstants.BROWSER_INTENT_PACKAGE + ".reading";
+    final long version = CURRENT_RL_PREFS_VERSION;
+    return constructPrefsPath(product, version, "");
+  }
+
+  public SharedPreferences getSyncPrefs() throws UnsupportedEncodingException, GeneralSecurityException {
+    return context.getSharedPreferences(getSyncPrefsPath(), Utils.SHARED_PREFERENCES_MODE);
+  }
+
+  public SharedPreferences getReadingListPrefs() throws UnsupportedEncodingException, GeneralSecurityException {
+    return context.getSharedPreferences(getReadingListPrefsPath(), Utils.SHARED_PREFERENCES_MODE);
+  }
+
+  /**
+   * Extract a JSON dictionary of the string values associated to this account.
+   * <p>
+   * <b>For debugging use only!</b> The contents of this JSON object completely
+   * determine the user's Firefox Account status and yield access to whatever
+   * user data the device has access to.
+   *
+   * @return JSON-object of Strings.
+   */
+  public ExtendedJSONObject toJSONObject() {
+    ExtendedJSONObject o = unbundle();
+    o.put("email", account.name);
+    try {
+      o.put("emailUTF8", Utils.byte2Hex(account.name.getBytes("UTF-8")));
+    } catch (UnsupportedEncodingException e) {
+      // Ignore.
+    }
+    o.put("fxaDeviceId", getDeviceId());
+    o.put("fxaDeviceRegistrationVersion", getDeviceRegistrationVersion());
+    return o;
+  }
+
+  public static AndroidFxAccount addAndroidAccount(
+      Context context,
+      String email,
+      String profile,
+      String idpServerURI,
+      String tokenServerURI,
+      String profileServerURI,
+      State state,
+      final Map<String, Boolean> authoritiesToSyncAutomaticallyMap)
+          throws UnsupportedEncodingException, GeneralSecurityException, URISyntaxException {
+    return addAndroidAccount(context, email, profile, idpServerURI, tokenServerURI, profileServerURI, state,
+        authoritiesToSyncAutomaticallyMap,
+        CURRENT_ACCOUNT_VERSION, false, null);
+  }
+
+  public static AndroidFxAccount addAndroidAccount(
+      Context context,
+      String email,
+      String profile,
+      String idpServerURI,
+      String tokenServerURI,
+      String profileServerURI,
+      State state,
+      final Map<String, Boolean> authoritiesToSyncAutomaticallyMap,
+      final int accountVersion,
+      final boolean fromPickle,
+      ExtendedJSONObject bundle)
+          throws UnsupportedEncodingException, GeneralSecurityException, URISyntaxException {
+    if (email == null) {
+      throw new IllegalArgumentException("email must not be null");
+    }
+    if (profile == null) {
+      throw new IllegalArgumentException("profile must not be null");
+    }
+    if (idpServerURI == null) {
+      throw new IllegalArgumentException("idpServerURI must not be null");
+    }
+    if (tokenServerURI == null) {
+      throw new IllegalArgumentException("tokenServerURI must not be null");
+    }
+    if (profileServerURI == null) {
+      throw new IllegalArgumentException("profileServerURI must not be null");
+    }
+    if (state == null) {
+      throw new IllegalArgumentException("state must not be null");
+    }
+
+    // TODO: Add migration code.
+    if (accountVersion != CURRENT_ACCOUNT_VERSION) {
+      throw new IllegalStateException("Could not create account of version " + accountVersion +
+          ". Current version is " + CURRENT_ACCOUNT_VERSION + ".");
+    }
+
+    // Android has internal restrictions that require all values in this
+    // bundle to be strings. *sigh*
+    Bundle userdata = new Bundle();
+    userdata.putString(ACCOUNT_KEY_ACCOUNT_VERSION, "" + CURRENT_ACCOUNT_VERSION);
+    userdata.putString(ACCOUNT_KEY_IDP_SERVER, idpServerURI);
+    userdata.putString(ACCOUNT_KEY_TOKEN_SERVER, tokenServerURI);
+    userdata.putString(ACCOUNT_KEY_PROFILE_SERVER, profileServerURI);
+    userdata.putString(ACCOUNT_KEY_PROFILE, profile);
+
+    if (bundle == null) {
+      bundle = new ExtendedJSONObject();
+      // TODO: How to upgrade?
+      bundle.put(BUNDLE_KEY_BUNDLE_VERSION, CURRENT_BUNDLE_VERSION);
+    }
+    bundle.put(BUNDLE_KEY_STATE_LABEL, state.getStateLabel().name());
+    bundle.put(BUNDLE_KEY_STATE, state.toJSONObject().toJSONString());
+
+    userdata.putString(ACCOUNT_KEY_DESCRIPTOR, bundle.toJSONString());
+
+    Account account = new Account(email, FxAccountConstants.ACCOUNT_TYPE);
+    AccountManager accountManager = AccountManager.get(context);
+    // We don't set an Android password, because we don't want to persist the
+    // password (or anything else as powerful as the password). Instead, we
+    // internally manage a sessionToken with a remotely owned lifecycle.
+    boolean added = accountManager.addAccountExplicitly(account, null, userdata);
+    if (!added) {
+      return null;
+    }
+
+    // Try to work around an intermittent issue described at
+    // http://stackoverflow.com/a/11698139.  What happens is that tests that
+    // delete and re-create the same account frequently will find the account
+    // missing all or some of the userdata bundle, possibly due to an Android
+    // AccountManager caching bug.
+    for (String key : userdata.keySet()) {
+      accountManager.setUserData(account, key, userdata.getString(key));
+    }
+
+    AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+
+    if (!fromPickle) {
+      fxAccount.clearSyncPrefs();
+    }
+
+    fxAccount.setAuthoritiesToSyncAutomaticallyMap(authoritiesToSyncAutomaticallyMap);
+
+    return fxAccount;
+  }
+
+  public void clearSyncPrefs() throws UnsupportedEncodingException, GeneralSecurityException {
+    getSyncPrefs().edit().clear().commit();
+  }
+
+  public void setAuthoritiesToSyncAutomaticallyMap(Map<String, Boolean> authoritiesToSyncAutomaticallyMap) {
+    if (authoritiesToSyncAutomaticallyMap == null) {
+      throw new IllegalArgumentException("authoritiesToSyncAutomaticallyMap must not be null");
+    }
+
+    for (String authority : DEFAULT_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP.keySet()) {
+      boolean authorityEnabled = DEFAULT_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP.get(authority);
+      final Boolean enabled = authoritiesToSyncAutomaticallyMap.get(authority);
+      if (enabled != null) {
+        authorityEnabled = enabled.booleanValue();
+      }
+      // Accounts are always capable of being synced ...
+      ContentResolver.setIsSyncable(account, authority, 1);
+      // ... but not always automatically synced.
+      ContentResolver.setSyncAutomatically(account, authority, authorityEnabled);
+    }
+  }
+
+  public Map<String, Boolean> getAuthoritiesToSyncAutomaticallyMap() {
+    final Map<String, Boolean> authoritiesToSync = new HashMap<>();
+    for (String authority : DEFAULT_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP.keySet()) {
+      final boolean enabled = ContentResolver.getSyncAutomatically(account, authority);
+      authoritiesToSync.put(authority, enabled);
+    }
+    return authoritiesToSync;
+  }
+
+  /**
+   * Is a sync currently in progress?
+   *
+   * @return true if Android is currently syncing the underlying Android Account.
+   */
+  public boolean isCurrentlySyncing() {
+    boolean active = false;
+    for (String authority : AndroidFxAccount.DEFAULT_AUTHORITIES_TO_SYNC_AUTOMATICALLY_MAP.keySet()) {
+      active |= ContentResolver.isSyncActive(account, authority);
+    }
+    return active;
+  }
+
+  /**
+   * Request an immediate sync.  Use this to sync as soon as possible in response to user action.
+   *
+   * @param stagesToSync stage names to sync; can be null to sync <b>all</b> known stages.
+   * @param stagesToSkip stage names to skip; can be null to skip <b>no</b> known stages.
+   */
+  public void requestImmediateSync(String[] stagesToSync, String[] stagesToSkip) {
+    FirefoxAccounts.requestImmediateSync(getAndroidAccount(), stagesToSync, stagesToSkip);
+  }
+
+  /**
+   * Request an eventual sync.  Use this to request the system queue a sync for some time in the
+   * future.
+   *
+   * @param stagesToSync stage names to sync; can be null to sync <b>all</b> known stages.
+   * @param stagesToSkip stage names to skip; can be null to skip <b>no</b> known stages.
+   */
+  public void requestEventualSync(String[] stagesToSync, String[] stagesToSkip) {
+    FirefoxAccounts.requestEventualSync(getAndroidAccount(), stagesToSync, stagesToSkip);
+  }
+
+  public synchronized void setState(State state) {
+    if (state == null) {
+      throw new IllegalArgumentException("state must not be null");
+    }
+    Logger.info(LOG_TAG, "Moving account named like " + getObfuscatedEmail() +
+        " to state " + state.getStateLabel().toString());
+    updateBundleValues(
+        BUNDLE_KEY_STATE_LABEL, state.getStateLabel().name(),
+        BUNDLE_KEY_STATE, state.toJSONObject().toJSONString());
+    broadcastAccountStateChangedIntent();
+  }
+
+  protected void broadcastAccountStateChangedIntent() {
+    final Intent intent = new Intent(FxAccountConstants.ACCOUNT_STATE_CHANGED_ACTION);
+    intent.putExtra(Constants.JSON_KEY_ACCOUNT, account.name);
+    LocalBroadcastManager.getInstance(context).sendBroadcast(intent);
+  }
+
+  public synchronized State getState() {
+    String stateLabelString = getBundleData(BUNDLE_KEY_STATE_LABEL);
+    String stateString = getBundleData(BUNDLE_KEY_STATE);
+    if (stateLabelString == null || stateString == null) {
+      throw new IllegalStateException("stateLabelString and stateString must not be null, but: " +
+          "(stateLabelString == null) = " + (stateLabelString == null) +
+          " and (stateString == null) = " + (stateString == null));
+    }
+
+    try {
+      StateLabel stateLabel = StateLabel.valueOf(stateLabelString);
+      Logger.debug(LOG_TAG, "Account is in state " + stateLabel);
+      return StateFactory.fromJSONObject(stateLabel, new ExtendedJSONObject(stateString));
+    } catch (Exception e) {
+      throw new IllegalStateException("could not get state", e);
+    }
+  }
+
+  public byte[] getSessionToken() throws InvalidFxAState {
+    State state = getState();
+    StateLabel stateLabel = state.getStateLabel();
+    if (stateLabel == StateLabel.Cohabiting || stateLabel == StateLabel.Married) {
+      TokensAndKeysState tokensAndKeysState = (TokensAndKeysState) state;
+      return tokensAndKeysState.getSessionToken();
+    }
+    throw new InvalidFxAState("Cannot get sessionToken: not in a TokensAndKeysState state");
+  }
+
+  public static class InvalidFxAState extends Exception {
+    private static final long serialVersionUID = -8537626959811195978L;
+
+    public InvalidFxAState(String message) {
+      super(message);
+    }
+  }
+
+  /**
+   * <b>For debugging only!</b>
+   */
+  public void dump() {
+    if (!FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+      return;
+    }
+    ExtendedJSONObject o = toJSONObject();
+    ArrayList<String> list = new ArrayList<String>(o.keySet());
+    Collections.sort(list);
+    for (String key : list) {
+      FxAccountUtils.pii(LOG_TAG, key + ": " + o.get(key));
+    }
+  }
+
+  /**
+   * Return the Firefox Account's local email address.
+   * <p>
+   * It is important to note that this is the local email address, and not
+   * necessarily the normalized remote email address that the server expects.
+   *
+   * @return local email address.
+   */
+  public String getEmail() {
+    return account.name;
+  }
+
+  /**
+   * Return the Firefox Account's local email address, obfuscated.
+   * <p>
+   * Use this when logging.
+   *
+   * @return local email address, obfuscated.
+   */
+  public String getObfuscatedEmail() {
+    return Utils.obfuscateEmail(account.name);
+  }
+
+  /**
+   * Populate an intent used for starting FxAccountDeletedService service.
+   *
+   * @param intent Intent to populate with necessary extras
+   * @return <code>Intent</code> with a deleted action and account/OAuth information extras
+   */
+  public Intent populateDeletedAccountIntent(final Intent intent) {
+    final List<String> tokens = new ArrayList<>();
+
+    intent.putExtra(FxAccountConstants.ACCOUNT_DELETED_INTENT_VERSION_KEY,
+        Long.valueOf(FxAccountConstants.ACCOUNT_DELETED_INTENT_VERSION));
+    intent.putExtra(FxAccountConstants.ACCOUNT_DELETED_INTENT_ACCOUNT_KEY, account.name);
+    intent.putExtra(FxAccountConstants.ACCOUNT_DELETED_INTENT_ACCOUNT_PROFILE, getProfile());
+
+    // Get the tokens from AccountManager. Note: currently, only reading list service supports OAuth. The following logic will
+    // be extended in future to support OAuth for other services.
+    for (String tokenKey : KNOWN_OAUTH_TOKEN_TYPES) {
+      final String authToken = accountManager.peekAuthToken(account, tokenKey);
+      if (authToken != null) {
+        tokens.add(authToken);
+      }
+    }
+
+    // Update intent with tokens and service URI.
+    intent.putExtra(FxAccountConstants.ACCOUNT_OAUTH_SERVICE_ENDPOINT_KEY, getOAuthServerURI());
+    // Deleted broadcasts are package-private, so there's no security risk include the tokens in the extras
+    intent.putExtra(FxAccountConstants.ACCOUNT_DELETED_INTENT_ACCOUNT_AUTH_TOKENS, tokens.toArray(new String[tokens.size()]));
+    return intent;
+  }
+
+  /**
+   * Create an intent announcing that the profile JSON attached to this Firefox Account has been updated.
+   * <p>
+   * It is not guaranteed that the profile JSON has changed.
+   *
+   * @return <code>Intent</code> to broadcast.
+   */
+  private Intent makeProfileJSONUpdatedIntent() {
+    final Intent intent = new Intent();
+    intent.setAction(FxAccountConstants.ACCOUNT_PROFILE_JSON_UPDATED_ACTION);
+    return intent;
+  }
+
+  public void setLastSyncedTimestamp(long now) {
+    try {
+      getSyncPrefs().edit().putLong(PREF_KEY_LAST_SYNCED_TIMESTAMP, now).commit();
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception setting last synced time; ignoring.", e);
+    }
+  }
+
+  public long getLastSyncedTimestamp() {
+    final long neverSynced = -1L;
+    try {
+      return getSyncPrefs().getLong(PREF_KEY_LAST_SYNCED_TIMESTAMP, neverSynced);
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception getting last synced time; ignoring.", e);
+      return neverSynced;
+    }
+  }
+
+  // Debug only!  This is dangerous!
+  public void unsafeTransitionToDefaultEndpoints() {
+    unsafeTransitionToStageEndpoints(
+        FxAccountConstants.DEFAULT_AUTH_SERVER_ENDPOINT,
+        FxAccountConstants.DEFAULT_TOKEN_SERVER_ENDPOINT,
+        FxAccountConstants.DEFAULT_PROFILE_SERVER_ENDPOINT);
+    }
+
+  // Debug only!  This is dangerous!
+  public void unsafeTransitionToStageEndpoints() {
+    unsafeTransitionToStageEndpoints(
+        FxAccountConstants.STAGE_AUTH_SERVER_ENDPOINT,
+        FxAccountConstants.STAGE_TOKEN_SERVER_ENDPOINT,
+        FxAccountConstants.STAGE_PROFILE_SERVER_ENDPOINT);
+  }
+
+  protected void unsafeTransitionToStageEndpoints(String authServerEndpoint, String tokenServerEndpoint, String profileServerEndpoint) {
+    try {
+      getReadingListPrefs().edit().clear().commit();
+    } catch (UnsupportedEncodingException | GeneralSecurityException e) {
+      // Ignore.
+    }
+    try {
+      getSyncPrefs().edit().clear().commit();
+    } catch (UnsupportedEncodingException | GeneralSecurityException e) {
+      // Ignore.
+    }
+    State state = getState();
+    setState(state.makeSeparatedState());
+    accountManager.setUserData(account, ACCOUNT_KEY_IDP_SERVER, authServerEndpoint);
+    accountManager.setUserData(account, ACCOUNT_KEY_TOKEN_SERVER, tokenServerEndpoint);
+    accountManager.setUserData(account, ACCOUNT_KEY_PROFILE_SERVER, profileServerEndpoint);
+    ContentResolver.setIsSyncable(account, BrowserContract.READING_LIST_AUTHORITY, 1);
+  }
+
+  /**
+   * Returns the current profile JSON if available, or null.
+   *
+   * @return profile JSON object.
+   */
+  public ExtendedJSONObject getProfileJSON() {
+    final String profileString = getBundleData(BUNDLE_KEY_PROFILE_JSON);
+    if (profileString == null) {
+      return null;
+    }
+
+    try {
+      return new ExtendedJSONObject(profileString);
+    } catch (Exception e) {
+      Logger.error(LOG_TAG, "Failed to parse profile JSON; ignoring and returning null.", e);
+    }
+    return null;
+  }
+
+  /**
+   * Fetch the profile JSON associated to the underlying Firefox Account from the server and update the local store.
+   * <p>
+   * The LocalBroadcastManager is used to notify the receivers asynchronously after a successful fetch.
+   */
+  public void fetchProfileJSON() {
+    ThreadUtils.postToBackgroundThread(new Runnable() {
+      @Override
+      public void run() {
+        // Fetch profile information from server.
+        String authToken;
+        try {
+          authToken = accountManager.blockingGetAuthToken(account, AndroidFxAccount.PROFILE_OAUTH_TOKEN_TYPE, true);
+          if (authToken == null) {
+            throw new RuntimeException("Couldn't get oauth token!  Aborting profile fetch.");
+          }
+        } catch (Exception e) {
+          Logger.error(LOG_TAG, "Error fetching profile information; ignoring.", e);
+          return;
+        }
+
+        Logger.info(LOG_TAG, "Intent service launched to fetch profile.");
+        final Intent intent = new Intent(context, FxAccountProfileService.class);
+        intent.putExtra(FxAccountProfileService.KEY_AUTH_TOKEN, authToken);
+        intent.putExtra(FxAccountProfileService.KEY_PROFILE_SERVER_URI, getProfileServerURI());
+        intent.putExtra(FxAccountProfileService.KEY_RESULT_RECEIVER, new ProfileResultReceiver(new Handler()));
+        context.startService(intent);
+      }
+    });
+  }
+
+  @Nullable
+  public synchronized String getDeviceId() {
+    return accountManager.getUserData(account, ACCOUNT_KEY_DEVICE_ID);
+  }
+
+  @NonNull
+  public synchronized int getDeviceRegistrationVersion() {
+    String versionStr = accountManager.getUserData(account, ACCOUNT_KEY_DEVICE_REGISTRATION_VERSION);
+    if (TextUtils.isEmpty(versionStr)) {
+      return 0;
+    } else {
+      try {
+        return Integer.parseInt(versionStr);
+      } catch (NumberFormatException ex) {
+        return 0;
+      }
+    }
+  }
+
+  public synchronized void setDeviceId(String id) {
+    accountManager.setUserData(account, ACCOUNT_KEY_DEVICE_ID, id);
+  }
+
+  public synchronized void setDeviceRegistrationVersion(int deviceRegistrationVersion) {
+    accountManager.setUserData(account, ACCOUNT_KEY_DEVICE_REGISTRATION_VERSION,
+        Integer.toString(deviceRegistrationVersion));
+  }
+
+  public synchronized void resetDeviceRegistrationVersion() {
+    setDeviceRegistrationVersion(0);
+  }
+
+  public synchronized void setFxAUserData(String id, int deviceRegistrationVersion) {
+    accountManager.setUserData(account, ACCOUNT_KEY_DEVICE_ID, id);
+    accountManager.setUserData(account, ACCOUNT_KEY_DEVICE_REGISTRATION_VERSION,
+        Integer.toString(deviceRegistrationVersion));
+  }
+
+  @SuppressLint("ParcelCreator") // The CREATOR field is defined in the super class.
+  private class ProfileResultReceiver extends ResultReceiver {
+    public ProfileResultReceiver(Handler handler) {
+      super(handler);
+    }
+
+    @Override
+    protected void onReceiveResult(int resultCode, Bundle bundle) {
+      super.onReceiveResult(resultCode, bundle);
+      switch (resultCode) {
+        case Activity.RESULT_OK:
+          final String resultData = bundle.getString(FxAccountProfileService.KEY_RESULT_STRING);
+          updateBundleValues(BUNDLE_KEY_PROFILE_JSON, resultData);
+          Logger.info(LOG_TAG, "Profile JSON fetch succeeeded!");
+          FxAccountUtils.pii(LOG_TAG, "Profile JSON fetch returned: " + resultData);
+          LocalBroadcastManager.getInstance(context).sendBroadcast(makeProfileJSONUpdatedIntent());
+          break;
+        case Activity.RESULT_CANCELED:
+          Logger.warn(LOG_TAG, "Failed to fetch profile JSON; ignoring.");
+          break;
+        default:
+          Logger.warn(LOG_TAG, "Invalid result code received; ignoring.");
+          break;
+      }
+    }
+  }
+
+  /**
+   * Take the lock to own updating any Firefox Account's internal state.
+   *
+   * We use a <code>Semaphore</code> rather than a <code>ReentrantLock</code>
+   * because the callback that needs to release the lock may not be invoked on
+   * the thread that initially acquired the lock. Be aware!
+   */
+  protected static final Semaphore sLock = new Semaphore(1, true /* fair */);
+
+  // Which consumer took the lock?
+  // Synchronized by this.
+  protected String lockTag = null;
+
+  // Are we locked?  (It's not easy to determine who took the lock dynamically,
+  // so we maintain this flag internally.)
+  // Synchronized by this.
+  protected boolean locked = false;
+
+  // Block until we can take the shared state lock.
+  public synchronized void acquireSharedAccountStateLock(final String tag) throws InterruptedException {
+    final long id = Thread.currentThread().getId();
+    this.lockTag = tag;
+    Log.d(Logger.DEFAULT_LOG_TAG, "Thread with tag and thread id acquiring lock: " + lockTag + ", " + id + " ...");
+    sLock.acquire();
+    locked = true;
+    Log.d(Logger.DEFAULT_LOG_TAG, "Thread with tag and thread id acquiring lock: " + lockTag + ", " + id + " ... ACQUIRED");
+  }
+
+  // If we hold the shared state lock, release it.  Otherwise, ignore the request.
+  public synchronized void releaseSharedAccountStateLock() {
+    final long id = Thread.currentThread().getId();
+    Log.d(Logger.DEFAULT_LOG_TAG, "Thread with tag and thread id releasing lock: " + lockTag + ", " + id + " ...");
+    if (locked) {
+      sLock.release();
+      locked = false;
+      Log.d(Logger.DEFAULT_LOG_TAG, "Thread with tag and thread id releasing lock: " + lockTag + ", " + id + " ... RELEASED");
+    } else {
+      Log.d(Logger.DEFAULT_LOG_TAG, "Thread with tag and thread id releasing lock: " + lockTag + ", " + id + " ... NOT LOCKED");
+    }
+  }
+
+  @Override
+  protected synchronized void finalize() {
+    if (locked) {
+      // Should never happen, but...
+      sLock.release();
+      locked = false;
+      final long id = Thread.currentThread().getId();
+      Log.e(Logger.DEFAULT_LOG_TAG, "Thread with tag and thread id releasing lock: " + lockTag + ", " + id + " ... RELEASED DURING FINALIZE");
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxADefaultLoginStateMachineDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxADefaultLoginStateMachineDelegate.java
new file mode 100644
index 000000000..ff3122322
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxADefaultLoginStateMachineDelegate.java
@@ -0,0 +1,84 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.authenticator;
+
+import java.security.NoSuchAlgorithmException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountClient;
+import org.mozilla.gecko.background.fxa.FxAccountClient20;
+import org.mozilla.gecko.browserid.BrowserIDKeyPair;
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.LoginStateMachineDelegate;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.Transition;
+import org.mozilla.gecko.fxa.login.Married;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.fxa.login.State.StateLabel;
+import org.mozilla.gecko.fxa.login.StateFactory;
+import org.mozilla.gecko.fxa.sync.FxAccountNotificationManager;
+import org.mozilla.gecko.fxa.sync.FxAccountSyncAdapter;
+
+import android.content.Context;
+
+public abstract class FxADefaultLoginStateMachineDelegate implements LoginStateMachineDelegate {
+  protected final static String LOG_TAG = LoginStateMachineDelegate.class.getSimpleName();
+
+  protected final Context context;
+  protected final AndroidFxAccount fxAccount;
+  protected final Executor executor;
+  protected final FxAccountClient client;
+
+  public FxADefaultLoginStateMachineDelegate(Context context, AndroidFxAccount fxAccount) {
+    this.context = context;
+    this.fxAccount = fxAccount;
+    this.executor = Executors.newSingleThreadExecutor();
+    this.client = new FxAccountClient20(fxAccount.getAccountServerURI(), executor);
+  }
+
+  abstract public void handleNotMarried(State notMarried);
+  abstract public void handleMarried(Married married);
+
+  @Override
+  public FxAccountClient getClient() {
+    return client;
+  }
+
+  @Override
+  public long getCertificateDurationInMilliseconds() {
+    return 12 * 60 * 60 * 1000;
+  }
+
+  @Override
+  public long getAssertionDurationInMilliseconds() {
+    return 15 * 60 * 1000;
+  }
+
+  @Override
+  public BrowserIDKeyPair generateKeyPair() throws NoSuchAlgorithmException {
+    return StateFactory.generateKeyPair();
+  }
+
+  @Override
+  public void handleTransition(Transition transition, State state) {
+    Logger.info(LOG_TAG, "handleTransition: " + transition + " to " + state.getStateLabel());
+  }
+
+  @Override
+  public void handleFinal(State state) {
+    Logger.info(LOG_TAG, "handleFinal: in " + state.getStateLabel());
+    fxAccount.setState(state);
+    // Update any notifications displayed.
+    final FxAccountNotificationManager notificationManager = new FxAccountNotificationManager(FxAccountSyncAdapter.NOTIFICATION_ID);
+    notificationManager.update(context, fxAccount);
+
+    if (state.getStateLabel() != StateLabel.Married) {
+      handleNotMarried(state);
+      return;
+    } else {
+      handleMarried((Married) state);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountAuthenticator.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountAuthenticator.java
new file mode 100644
index 000000000..259b1cb88
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountAuthenticator.java
@@ -0,0 +1,385 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.authenticator;
+
+import android.accounts.AbstractAccountAuthenticator;
+import android.accounts.Account;
+import android.accounts.AccountAuthenticatorResponse;
+import android.accounts.AccountManager;
+import android.accounts.NetworkErrorException;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountClient;
+import org.mozilla.gecko.background.fxa.FxAccountClient20;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountAbstractClient.RequestDelegate;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountAbstractClientException.FxAccountAbstractClientRemoteException;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountOAuthClient10;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountOAuthClient10.AuthorizationResponse;
+import org.mozilla.gecko.browserid.BrowserIDKeyPair;
+import org.mozilla.gecko.browserid.JSONWebTokenUtils;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine;
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.LoginStateMachineDelegate;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.Transition;
+import org.mozilla.gecko.fxa.login.Married;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.fxa.login.State.StateLabel;
+import org.mozilla.gecko.fxa.login.StateFactory;
+import org.mozilla.gecko.fxa.receivers.FxAccountDeletedService;
+import org.mozilla.gecko.fxa.sync.FxAccountNotificationManager;
+import org.mozilla.gecko.fxa.sync.FxAccountSyncAdapter;
+import org.mozilla.gecko.util.ThreadUtils;
+
+import java.security.NoSuchAlgorithmException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+
+public class FxAccountAuthenticator extends AbstractAccountAuthenticator {
+  public static final String LOG_TAG = FxAccountAuthenticator.class.getSimpleName();
+  public static final int UNKNOWN_ERROR_CODE = 999;
+
+  protected final Context context;
+  protected final AccountManager accountManager;
+
+  public FxAccountAuthenticator(Context context) {
+    super(context);
+    this.context = context;
+    this.accountManager = AccountManager.get(context);
+  }
+
+  @Override
+  public Bundle addAccount(AccountAuthenticatorResponse response,
+      String accountType, String authTokenType, String[] requiredFeatures,
+      Bundle options)
+          throws NetworkErrorException {
+    Logger.debug(LOG_TAG, "addAccount");
+
+    // The data associated to each Account should be invalidated when we change
+    // the set of Firefox Accounts on the system.
+    AndroidFxAccount.invalidateCaches();
+
+    final Bundle res = new Bundle();
+
+    if (!FxAccountConstants.ACCOUNT_TYPE.equals(accountType)) {
+      res.putInt(AccountManager.KEY_ERROR_CODE, -1);
+      res.putString(AccountManager.KEY_ERROR_MESSAGE, "Not adding unknown account type.");
+      return res;
+    }
+
+    final Intent intent = new Intent(FxAccountConstants.ACTION_FXA_GET_STARTED);
+    res.putParcelable(AccountManager.KEY_INTENT, intent);
+    return res;
+  }
+
+  @Override
+  public Bundle confirmCredentials(AccountAuthenticatorResponse response, Account account, Bundle options)
+      throws NetworkErrorException {
+    Logger.debug(LOG_TAG, "confirmCredentials");
+
+    return null;
+  }
+
+  @Override
+  public Bundle editProperties(AccountAuthenticatorResponse response, String accountType) {
+    Logger.debug(LOG_TAG, "editProperties");
+
+    return null;
+  }
+
+  protected static class Responder {
+    final AccountAuthenticatorResponse response;
+    final AndroidFxAccount fxAccount;
+
+    public Responder(AccountAuthenticatorResponse response, AndroidFxAccount fxAccount) {
+      this.response = response;
+      this.fxAccount = fxAccount;
+    }
+
+    public void fail(Exception e) {
+      Logger.warn(LOG_TAG, "Responding with error!", e);
+      fxAccount.releaseSharedAccountStateLock();
+      final Bundle result = new Bundle();
+      result.putInt(AccountManager.KEY_ERROR_CODE, UNKNOWN_ERROR_CODE);
+      result.putString(AccountManager.KEY_ERROR_MESSAGE, e.toString());
+      response.onResult(result);
+    }
+
+    public void succeed(String authToken) {
+      Logger.info(LOG_TAG, "Responding with success!");
+      fxAccount.releaseSharedAccountStateLock();
+      final Bundle result = new Bundle();
+      result.putString(AccountManager.KEY_ACCOUNT_NAME, fxAccount.account.name);
+      result.putString(AccountManager.KEY_ACCOUNT_TYPE, fxAccount.account.type);
+      result.putString(AccountManager.KEY_AUTHTOKEN, authToken);
+      response.onResult(result);
+    }
+  }
+
+  public abstract static class FxADefaultLoginStateMachineDelegate implements LoginStateMachineDelegate {
+    protected final Context context;
+    protected final AndroidFxAccount fxAccount;
+    protected final Executor executor;
+    protected final FxAccountClient client;
+
+    public FxADefaultLoginStateMachineDelegate(Context context, AndroidFxAccount fxAccount) {
+      this.context = context;
+      this.fxAccount = fxAccount;
+      this.executor = Executors.newSingleThreadExecutor();
+      this.client = new FxAccountClient20(fxAccount.getAccountServerURI(), executor);
+    }
+
+    @Override
+    public FxAccountClient getClient() {
+      return client;
+    }
+
+    @Override
+    public long getCertificateDurationInMilliseconds() {
+      return 12 * 60 * 60 * 1000;
+    }
+
+    @Override
+    public long getAssertionDurationInMilliseconds() {
+      return 15 * 60 * 1000;
+    }
+
+    @Override
+    public BrowserIDKeyPair generateKeyPair() throws NoSuchAlgorithmException {
+      return StateFactory.generateKeyPair();
+    }
+
+    @Override
+    public void handleTransition(Transition transition, State state) {
+      Logger.info(LOG_TAG, "handleTransition: " + transition + " to " + state.getStateLabel());
+    }
+
+    abstract public void handleNotMarried(State notMarried);
+    abstract public void handleMarried(Married married);
+
+    @Override
+    public void handleFinal(State state) {
+      Logger.info(LOG_TAG, "handleFinal: in " + state.getStateLabel());
+      fxAccount.setState(state);
+      // Update any notifications displayed.
+      final FxAccountNotificationManager notificationManager = new FxAccountNotificationManager(FxAccountSyncAdapter.NOTIFICATION_ID);
+      notificationManager.update(context, fxAccount);
+
+      if (state.getStateLabel() != StateLabel.Married) {
+        handleNotMarried(state);
+        return;
+      } else {
+        handleMarried((Married) state);
+      }
+    }
+  }
+
+  protected void getOAuthToken(final AccountAuthenticatorResponse response, final AndroidFxAccount fxAccount, final String scope) throws NetworkErrorException {
+    Logger.info(LOG_TAG, "Fetching oauth token with scope: " + scope);
+
+    final Responder responder = new Responder(response, fxAccount);
+    final String oauthServerUri = fxAccount.getOAuthServerURI();
+
+    final String audience;
+    try {
+      audience = FxAccountUtils.getAudienceForURL(oauthServerUri); // The assertion gets traded in for an oauth bearer token.
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception fetching oauth token.", e);
+      responder.fail(e);
+      return;
+    }
+
+    final FxAccountLoginStateMachine stateMachine = new FxAccountLoginStateMachine();
+
+    stateMachine.advance(fxAccount.getState(), StateLabel.Married, new FxADefaultLoginStateMachineDelegate(context, fxAccount) {
+      @Override
+      public void handleNotMarried(State state) {
+        final String message = "Cannot fetch oauth token from state: " + state.getStateLabel();
+        Logger.warn(LOG_TAG, message);
+        responder.fail(new RuntimeException(message));
+      }
+
+      @Override
+      public void handleMarried(final Married married) {
+        final String assertion;
+        try {
+          assertion = married.generateAssertion(audience, JSONWebTokenUtils.DEFAULT_ASSERTION_ISSUER);
+          if (FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+            JSONWebTokenUtils.dumpAssertion(assertion);
+          }
+        } catch (Exception e) {
+          Logger.warn(LOG_TAG, "Got exception fetching oauth token.", e);
+          responder.fail(e);
+          return;
+        }
+
+        final FxAccountOAuthClient10 oauthClient = new FxAccountOAuthClient10(oauthServerUri, executor);
+        Logger.debug(LOG_TAG, "OAuth fetch for scope: " + scope);
+        oauthClient.authorization(FxAccountConstants.OAUTH_CLIENT_ID_FENNEC, assertion, null, scope, new RequestDelegate<FxAccountOAuthClient10.AuthorizationResponse>() {
+          @Override
+          public void handleSuccess(AuthorizationResponse result) {
+            Logger.debug(LOG_TAG, "OAuth success.");
+            FxAccountUtils.pii(LOG_TAG, "Fetched oauth token: " + result.access_token);
+            responder.succeed(result.access_token);
+          }
+
+          @Override
+          public void handleFailure(FxAccountAbstractClientRemoteException e) {
+            Logger.error(LOG_TAG, "OAuth failure.", e);
+            if (e.isInvalidAuthentication()) {
+              // We were married, generated an assertion, and our assertion was rejected by the
+              // oauth client. If it's a 401, we probably have a stale certificate.  If instead of
+              // a stale certificate we have bad credentials, the state machine will fail to sign
+              // our public key and drive us back to Separated.
+              fxAccount.setState(married.makeCohabitingState());
+            }
+            responder.fail(e);
+          }
+
+          @Override
+          public void handleError(Exception e) {
+            Logger.error(LOG_TAG, "OAuth error.", e);
+            responder.fail(e);
+          }
+        });
+      }
+    });
+  }
+
+  @Override
+  public Bundle getAuthToken(final AccountAuthenticatorResponse response,
+      final Account account, final String authTokenType, final Bundle options)
+          throws NetworkErrorException {
+    Logger.debug(LOG_TAG, "getAuthToken: " + authTokenType);
+
+    // If we have a cached authToken, hand it over.
+    final String cachedAuthToken = AccountManager.get(context).peekAuthToken(account, authTokenType);
+    if (cachedAuthToken != null && !cachedAuthToken.isEmpty()) {
+      Logger.info(LOG_TAG, "Return cached token.");
+      final Bundle result = new Bundle();
+      result.putString(AccountManager.KEY_ACCOUNT_NAME, account.name);
+      result.putString(AccountManager.KEY_ACCOUNT_TYPE, account.type);
+      result.putString(AccountManager.KEY_AUTHTOKEN, cachedAuthToken);
+      return result;
+    }
+
+    // If we're asked for an oauth::scope token, try to generate one.
+    final String oauthPrefix = "oauth::";
+    if (authTokenType != null && authTokenType.startsWith(oauthPrefix)) {
+      final String scope = authTokenType.substring(oauthPrefix.length());
+      final AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+      try {
+        fxAccount.acquireSharedAccountStateLock(LOG_TAG);
+      } catch (InterruptedException e) {
+        Logger.warn(LOG_TAG, "Could not acquire account state lock; return error bundle.");
+        final Bundle bundle = new Bundle();
+        bundle.putInt(AccountManager.KEY_ERROR_CODE, 1);
+        bundle.putString(AccountManager.KEY_ERROR_MESSAGE, "Could not acquire account state lock.");
+        return bundle;
+      }
+      getOAuthToken(response, fxAccount, scope);
+      return null;
+    }
+
+    // Otherwise, fail.
+    Logger.warn(LOG_TAG, "Returning error bundle for getAuthToken with unknown token type.");
+    final Bundle bundle = new Bundle();
+    bundle.putInt(AccountManager.KEY_ERROR_CODE, 2);
+    bundle.putString(AccountManager.KEY_ERROR_MESSAGE, "Unknown token type: " + authTokenType);
+    return bundle;
+  }
+
+  @Override
+  public String getAuthTokenLabel(String authTokenType) {
+    Logger.debug(LOG_TAG, "getAuthTokenLabel");
+
+    return null;
+  }
+
+  @Override
+  public Bundle hasFeatures(AccountAuthenticatorResponse response,
+      Account account, String[] features) throws NetworkErrorException {
+    Logger.debug(LOG_TAG, "hasFeatures");
+
+    return null;
+  }
+
+  @Override
+  public Bundle updateCredentials(AccountAuthenticatorResponse response,
+      Account account, String authTokenType, Bundle options)
+          throws NetworkErrorException {
+    Logger.debug(LOG_TAG, "updateCredentials");
+
+    return null;
+  }
+
+  /**
+   * If the account is going to be removed, broadcast an "account deleted"
+   * intent. This allows us to clean up the account.
+   * <p>
+   * It is preferable to receive Android's LOGIN_ACCOUNTS_CHANGED_ACTION broadcast
+   * than to create our own hacky broadcast here, but that doesn't include enough
+   * information about which Accounts changed to correctly identify whether a Sync
+   * account has been removed (when some Firefox channels are installed on the SD
+   * card). We can work around this by storing additional state but it's both messy
+   * and expensive because the broadcast is noisy.
+   * <p>
+   * Note that this is <b>not</b> called when an Android Account is blown away
+   * due to the SD card being unmounted.
+   */
+  @Override
+  public Bundle getAccountRemovalAllowed(final AccountAuthenticatorResponse response, Account account)
+      throws NetworkErrorException {
+    Bundle result = super.getAccountRemovalAllowed(response, account);
+
+    if (result == null ||
+        !result.containsKey(AccountManager.KEY_BOOLEAN_RESULT) ||
+        result.containsKey(AccountManager.KEY_INTENT)) {
+      return result;
+    }
+
+    final boolean removalAllowed = result.getBoolean(AccountManager.KEY_BOOLEAN_RESULT);
+    if (!removalAllowed) {
+      return result;
+    }
+
+    // Broadcast a message to all Firefox channels sharing this Android
+    // Account type telling that this Firefox account has been deleted.
+    //
+    // Broadcast intents protected with permissions are secure, so it's okay
+    // to include private information such as a password.
+    final AndroidFxAccount androidFxAccount = new AndroidFxAccount(context, account);
+
+    // Deleting the pickle file in a blocking manner will avoid race conditions that might happen when
+    // an account is unpickled while an FxAccount is being deleted.
+    // Also we have an assumption that this method is always called from a background thread, so we delete
+    // the pickle file directly without being afraid from a StrictMode violation.
+    ThreadUtils.assertNotOnUiThread();
+
+    final Intent serviceIntent = androidFxAccount.populateDeletedAccountIntent(
+            new Intent(context, FxAccountDeletedService.class)
+    );
+    Logger.info(LOG_TAG, "Account named " + account.name + " being removed; " +
+        "starting FxAccountDeletedService with action: " + serviceIntent.getAction() + ".");
+    context.startService(serviceIntent);
+
+    Logger.info(LOG_TAG, "Firefox account named " + account.name + " being removed; " +
+            "deleting saved pickle file '" + FxAccountConstants.ACCOUNT_PICKLE_FILENAME + "'.");
+    deletePickle();
+
+    return result;
+  }
+
+  private void deletePickle() {
+    try {
+      AccountPickler.deletePickle(context, FxAccountConstants.ACCOUNT_PICKLE_FILENAME);
+    } catch (Exception e) {
+      // This should never happen, but we really don't want to die in a background thread.
+      Logger.warn(LOG_TAG, "Got exception deleting saved pickle file; ignoring.", e);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountAuthenticatorService.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountAuthenticatorService.java
new file mode 100644
index 000000000..d138e6c45
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountAuthenticatorService.java
@@ -0,0 +1,55 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.authenticator;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+import android.app.Service;
+import android.content.Intent;
+import android.os.IBinder;
+
+public class FxAccountAuthenticatorService extends Service {
+  public static final String LOG_TAG = FxAccountAuthenticatorService.class.getSimpleName();
+
+  // Lazily initialized by <code>getAuthenticator</code>.
+  protected FxAccountAuthenticator accountAuthenticator;
+
+  protected synchronized FxAccountAuthenticator getAuthenticator() {
+    if (accountAuthenticator == null) {
+      accountAuthenticator = new FxAccountAuthenticator(this);
+    }
+
+    return accountAuthenticator;
+  }
+
+  @Override
+  public void onCreate() {
+    Logger.debug(LOG_TAG, "onCreate");
+
+    accountAuthenticator = getAuthenticator();
+  }
+
+  @Override
+  public IBinder onBind(Intent intent) {
+    Logger.debug(LOG_TAG, "onBind");
+
+    if (intent == null) {
+      // Should never happen, but can -- Bug 1025937.
+      return null;
+    }
+
+    if (!android.accounts.AccountManager.ACTION_AUTHENTICATOR_INTENT.equals(intent.getAction())) {
+      return null;
+    }
+
+    final FxAccountAuthenticator authenticator = getAuthenticator();
+    if (authenticator == null) {
+      // Should never happen.
+      return null;
+    }
+
+    return authenticator.getIBinder();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountLoginDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountLoginDelegate.java
new file mode 100644
index 000000000..71006e79d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountLoginDelegate.java
@@ -0,0 +1,26 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.authenticator;
+
+/**
+ * Abstraction around things that might need to be signalled to the user via UI,
+ * such as:
+ * <ul>
+ * <li>account not yet verified;</li>
+ * <li>account password needs to be updated;</li>
+ * <li>account key management required or changed;</li>
+ * <li>auth protocol has changed and Firefox needs to be upgraded;</li>
+ * </ul>
+ * etc.
+ * <p>
+ * Consumers of this code should differentiate error classes based on the types
+ * of the exceptions thrown. Exceptions that do not have special meaning are of
+ * type <code>FxAccountLoginException</code> with an appropriate
+ * <code>cause</code> inner exception.
+ */
+public interface FxAccountLoginDelegate {
+  public void handleError(FxAccountLoginException e);
+  public void handleSuccess(String assertion);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountLoginException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountLoginException.java
new file mode 100644
index 000000000..56c0140b2
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/authenticator/FxAccountLoginException.java
@@ -0,0 +1,33 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.authenticator;
+
+public class FxAccountLoginException extends Exception {
+  public FxAccountLoginException(String string) {
+    super(string);
+  }
+
+  public FxAccountLoginException(Exception e) {
+    super(e);
+  }
+
+  private static final long serialVersionUID = 397685959625820798L;
+
+  public static class FxAccountLoginBadPasswordException extends FxAccountLoginException {
+    public FxAccountLoginBadPasswordException(String string) {
+      super(string);
+    }
+
+    private static final long serialVersionUID = 397685959625820799L;
+  }
+
+  public static class FxAccountLoginAccountNotVerifiedException extends FxAccountLoginException {
+    public FxAccountLoginAccountNotVerifiedException(String string) {
+      super(string);
+    }
+
+    private static final long serialVersionUID = 397685959625820800L;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/BaseRequestDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/BaseRequestDelegate.java
new file mode 100644
index 000000000..5d3e71ece
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/BaseRequestDelegate.java
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import org.mozilla.gecko.background.fxa.FxAccountClient20;
+import org.mozilla.gecko.background.fxa.FxAccountClientException.FxAccountClientRemoteException;
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.ExecuteDelegate;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.AccountNeedsVerification;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.LocalError;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.RemoteError;
+
+public abstract class BaseRequestDelegate<T> implements FxAccountClient20.RequestDelegate<T> {
+  protected final ExecuteDelegate delegate;
+  protected final State state;
+
+  public BaseRequestDelegate(State state, ExecuteDelegate delegate) {
+    this.delegate = delegate;
+    this.state = state;
+  }
+
+  @Override
+  public void handleFailure(FxAccountClientRemoteException e) {
+    // Order matters here: we don't want to ignore upgrade required responses
+    // even if the server tells us something else as well. We don't go directly
+    // to the Doghouse on upgrade required; we want the user to try to update
+    // their credentials, and then display UI telling them they need to upgrade.
+    // Then they go to the Doghouse.
+    if (e.isUpgradeRequired()) {
+      delegate.handleTransition(new RemoteError(e), new Separated(state.email, state.uid, state.verified));
+      return;
+    }
+    if (e.isInvalidAuthentication()) {
+      delegate.handleTransition(new RemoteError(e), new Separated(state.email, state.uid, state.verified));
+      return;
+    }
+    if (e.isUnverified()) {
+      delegate.handleTransition(new AccountNeedsVerification(), state);
+      return;
+    }
+    delegate.handleTransition(new RemoteError(e), state);
+  }
+
+  @Override
+  public void handleError(Exception e) {
+    delegate.handleTransition(new LocalError(e), state);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Cohabiting.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Cohabiting.java
new file mode 100644
index 000000000..dd3477a79
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Cohabiting.java
@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.browserid.BrowserIDKeyPair;
+import org.mozilla.gecko.browserid.JSONWebTokenUtils;
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.ExecuteDelegate;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.LogMessage;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+public class Cohabiting extends TokensAndKeysState {
+  private static final String LOG_TAG = Cohabiting.class.getSimpleName();
+
+  public Cohabiting(String email, String uid, byte[] sessionToken, byte[] kA, byte[] kB, BrowserIDKeyPair keyPair) {
+    super(StateLabel.Cohabiting, email, uid, sessionToken, kA, kB, keyPair);
+  }
+
+  public Married withCertificate(String certificate) {
+    return new Married(email, uid, sessionToken, kA, kB, keyPair, certificate);
+  }
+
+  @Override
+  public void execute(final ExecuteDelegate delegate) {
+    delegate.getClient().sign(sessionToken, keyPair.getPublic().toJSONObject(), delegate.getCertificateDurationInMilliseconds(),
+        new BaseRequestDelegate<String>(this, delegate) {
+      @Override
+      public void handleSuccess(String certificate) {
+        if (FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+          try {
+            FxAccountUtils.pii(LOG_TAG, "Fetched certificate: " + certificate);
+            ExtendedJSONObject c = JSONWebTokenUtils.parseCertificate(certificate);
+            if (c != null) {
+              FxAccountUtils.pii(LOG_TAG, "Header   : " + c.getObject("header"));
+              FxAccountUtils.pii(LOG_TAG, "Payload  : " + c.getObject("payload"));
+              FxAccountUtils.pii(LOG_TAG, "Signature: " + c.getString("signature"));
+            } else {
+              FxAccountUtils.pii(LOG_TAG, "Could not parse certificate!");
+            }
+          } catch (Exception e) {
+            FxAccountUtils.pii(LOG_TAG, "Could not parse certificate!");
+          }
+        }
+        delegate.handleTransition(new LogMessage("sign succeeded"), withCertificate(certificate));
+      }
+    });
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Doghouse.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Doghouse.java
new file mode 100644
index 000000000..57600577d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Doghouse.java
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.ExecuteDelegate;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.LogMessage;
+
+
+public class Doghouse extends State {
+  public Doghouse(String email, String uid, boolean verified) {
+    super(StateLabel.Doghouse, email, uid, verified);
+  }
+
+  @Override
+  public void execute(final ExecuteDelegate delegate) {
+    delegate.handleTransition(new LogMessage("Upgraded Firefox clients might know what to do here."), this);
+  }
+
+  @Override
+  public Action getNeededAction() {
+    return Action.NeedsUpgrade;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Engaged.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Engaged.java
new file mode 100644
index 000000000..f192cb58b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Engaged.java
@@ -0,0 +1,91 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import java.security.NoSuchAlgorithmException;
+
+import org.mozilla.gecko.background.fxa.FxAccountClient20.TwoKeys;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.browserid.BrowserIDKeyPair;
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.ExecuteDelegate;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.AccountVerified;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.LocalError;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.LogMessage;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.RemoteError;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.Transition;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.Utils;
+
+public class Engaged extends State {
+  private static final String LOG_TAG = Engaged.class.getSimpleName();
+
+  protected final byte[] sessionToken;
+  protected final byte[] keyFetchToken;
+  protected final byte[] unwrapkB;
+
+  public Engaged(String email, String uid, boolean verified, byte[] unwrapkB, byte[] sessionToken, byte[] keyFetchToken) {
+    super(StateLabel.Engaged, email, uid, verified);
+    Utils.throwIfNull(unwrapkB, sessionToken, keyFetchToken);
+    this.unwrapkB = unwrapkB;
+    this.sessionToken = sessionToken;
+    this.keyFetchToken = keyFetchToken;
+  }
+
+  @Override
+  public ExtendedJSONObject toJSONObject() {
+    ExtendedJSONObject o = super.toJSONObject();
+    // Fields are non-null by constructor.
+    o.put("unwrapkB", Utils.byte2Hex(unwrapkB));
+    o.put("sessionToken", Utils.byte2Hex(sessionToken));
+    o.put("keyFetchToken", Utils.byte2Hex(keyFetchToken));
+    return o;
+  }
+
+  @Override
+  public void execute(final ExecuteDelegate delegate) {
+    BrowserIDKeyPair theKeyPair;
+    try {
+      theKeyPair = delegate.generateKeyPair();
+    } catch (NoSuchAlgorithmException e) {
+      delegate.handleTransition(new LocalError(e), new Doghouse(email, uid, verified));
+      return;
+    }
+    final BrowserIDKeyPair keyPair = theKeyPair;
+
+    delegate.getClient().keys(keyFetchToken, new BaseRequestDelegate<TwoKeys>(this, delegate) {
+      @Override
+      public void handleSuccess(TwoKeys result) {
+        byte[] kB;
+        try {
+          kB = FxAccountUtils.unwrapkB(unwrapkB, result.wrapkB);
+          if (FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+            FxAccountUtils.pii(LOG_TAG, "Fetched kA: " + Utils.byte2Hex(result.kA));
+            FxAccountUtils.pii(LOG_TAG, "And wrapkB: " + Utils.byte2Hex(result.wrapkB));
+            FxAccountUtils.pii(LOG_TAG, "Giving kB : " + Utils.byte2Hex(kB));
+          }
+        } catch (Exception e) {
+          delegate.handleTransition(new RemoteError(e), new Separated(email, uid, verified));
+          return;
+        }
+        Transition transition = verified
+            ? new LogMessage("keys succeeded")
+            : new AccountVerified();
+        delegate.handleTransition(transition, new Cohabiting(email, uid, sessionToken, result.kA, kB, keyPair));
+      }
+    });
+  }
+
+  @Override
+  public Action getNeededAction() {
+    if (!verified) {
+      return Action.NeedsVerification;
+    }
+    return Action.None;
+  }
+
+  public byte[] getSessionToken() {
+    return sessionToken;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/FxAccountLoginStateMachine.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/FxAccountLoginStateMachine.java
new file mode 100644
index 000000000..34e507541
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/FxAccountLoginStateMachine.java
@@ -0,0 +1,84 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import java.security.NoSuchAlgorithmException;
+import java.util.EnumSet;
+import java.util.Set;
+
+import org.mozilla.gecko.background.fxa.FxAccountClient;
+import org.mozilla.gecko.browserid.BrowserIDKeyPair;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.Transition;
+import org.mozilla.gecko.fxa.login.State.StateLabel;
+
+public class FxAccountLoginStateMachine {
+  public static final String LOG_TAG = FxAccountLoginStateMachine.class.getSimpleName();
+
+  public interface LoginStateMachineDelegate {
+    public FxAccountClient getClient();
+    public long getCertificateDurationInMilliseconds();
+    public long getAssertionDurationInMilliseconds();
+    public void handleTransition(Transition transition, State state);
+    public void handleFinal(State state);
+    public BrowserIDKeyPair generateKeyPair() throws NoSuchAlgorithmException;
+  }
+
+  public static class ExecuteDelegate {
+    protected final LoginStateMachineDelegate delegate;
+    protected final StateLabel desiredStateLabel;
+    // It's as difficult to detect arbitrary cycles as repeated states.
+    protected final Set<StateLabel> stateLabelsSeen = EnumSet.noneOf(StateLabel.class);
+
+    protected ExecuteDelegate(StateLabel initialStateLabel, StateLabel desiredStateLabel, LoginStateMachineDelegate delegate) {
+      this.delegate = delegate;
+      this.desiredStateLabel = desiredStateLabel;
+      this.stateLabelsSeen.add(initialStateLabel);
+    }
+
+    public FxAccountClient getClient() {
+      return delegate.getClient();
+    }
+
+    public long getCertificateDurationInMilliseconds() {
+      return delegate.getCertificateDurationInMilliseconds();
+    }
+
+    public long getAssertionDurationInMilliseconds() {
+      return delegate.getAssertionDurationInMilliseconds();
+    }
+
+    public BrowserIDKeyPair generateKeyPair() throws NoSuchAlgorithmException {
+      return delegate.generateKeyPair();
+    }
+
+    public void handleTransition(Transition transition, State state) {
+      // Always trigger the transition callback.
+      delegate.handleTransition(transition, state);
+
+      // Possibly trigger the final callback. We trigger if we're at our desired
+      // state, or if we've seen this state before.
+      StateLabel stateLabel = state.getStateLabel();
+      if (stateLabel == desiredStateLabel || stateLabelsSeen.contains(stateLabel)) {
+        delegate.handleFinal(state);
+        return;
+      }
+
+      // If this wasn't the last state, leave a bread crumb and move on to the
+      // next state.
+      stateLabelsSeen.add(stateLabel);
+      state.execute(this);
+    }
+  }
+
+  public void advance(State initialState, final StateLabel desiredStateLabel, final LoginStateMachineDelegate delegate) {
+    if (initialState.getStateLabel() == desiredStateLabel) {
+      // We're already where we want to be!
+      delegate.handleFinal(initialState);
+      return;
+    }
+    ExecuteDelegate executeDelegate = new ExecuteDelegate(initialState.getStateLabel(), desiredStateLabel, delegate);
+    initialState.execute(executeDelegate);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/FxAccountLoginTransition.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/FxAccountLoginTransition.java
new file mode 100644
index 000000000..683217853
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/FxAccountLoginTransition.java
@@ -0,0 +1,68 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+
+public class FxAccountLoginTransition {
+  public interface Transition {
+  }
+
+  public static class LogMessage implements Transition {
+    public final String detailMessage;
+
+    public LogMessage(String detailMessage) {
+      this.detailMessage = detailMessage;
+    }
+
+    @Override
+    public String toString() {
+      return getClass().getSimpleName() + (this.detailMessage == null ? "" : "('" + this.detailMessage + "')");
+    }
+  }
+
+  public static class AccountNeedsVerification extends LogMessage {
+    public AccountNeedsVerification() {
+      super(null);
+    }
+  }
+
+  public static class AccountVerified extends LogMessage {
+    public AccountVerified() {
+      super(null);
+    }
+  }
+
+  public static class PasswordRequired extends LogMessage {
+    public PasswordRequired() {
+      super(null);
+    }
+  }
+
+  public static class LocalError implements Transition {
+    public final Exception e;
+
+    public LocalError(Exception e) {
+      this.e = e;
+    }
+
+    @Override
+    public String toString() {
+      return "Log(" + this.e + ")";
+    }
+  }
+
+  public static class RemoteError implements Transition {
+    public final Exception e;
+
+    public RemoteError(Exception e) {
+      this.e = e;
+    }
+
+    @Override
+    public String toString() {
+      return "Log(" + (this.e == null ? "null" : this.e) + ")";
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Married.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Married.java
new file mode 100644
index 000000000..1ec7b4051
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Married.java
@@ -0,0 +1,117 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.browserid.BrowserIDKeyPair;
+import org.mozilla.gecko.browserid.JSONWebTokenUtils;
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.ExecuteDelegate;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.LogMessage;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+
+public class Married extends TokensAndKeysState {
+  private static final String LOG_TAG = Married.class.getSimpleName();
+
+  protected final String certificate;
+  protected final String clientState;
+
+  public Married(String email, String uid, byte[] sessionToken, byte[] kA, byte[] kB, BrowserIDKeyPair keyPair, String certificate) {
+    super(StateLabel.Married, email, uid, sessionToken, kA, kB, keyPair);
+    Utils.throwIfNull(certificate);
+    this.certificate = certificate;
+    try {
+      this.clientState = FxAccountUtils.computeClientState(kB);
+    } catch (NoSuchAlgorithmException e) {
+      // This should never occur.
+      throw new IllegalStateException("Unable to compute client state from kB.");
+    }
+  }
+
+  @Override
+  public ExtendedJSONObject toJSONObject() {
+    ExtendedJSONObject o = super.toJSONObject();
+    // Fields are non-null by constructor.
+    o.put("certificate", certificate);
+    return o;
+  }
+
+  @Override
+  public void execute(final ExecuteDelegate delegate) {
+    delegate.handleTransition(new LogMessage("staying married"), this);
+  }
+
+  public String generateAssertion(String audience, String issuer) throws NonObjectJSONException, IOException, GeneralSecurityException {
+    // We generate assertions with no iat and an exp after 2050 to avoid
+    // invalid-timestamp errors from the token server.
+    final long expiresAt = JSONWebTokenUtils.DEFAULT_FUTURE_EXPIRES_AT_IN_MILLISECONDS;
+    String assertion = JSONWebTokenUtils.createAssertion(keyPair.getPrivate(), certificate, audience, issuer, null, expiresAt);
+    if (!FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+      return assertion;
+    }
+
+    try {
+      FxAccountUtils.pii(LOG_TAG, "Generated assertion: " + assertion);
+      ExtendedJSONObject a = JSONWebTokenUtils.parseAssertion(assertion);
+      if (a != null) {
+        FxAccountUtils.pii(LOG_TAG, "aHeader   : " + a.getObject("header"));
+        FxAccountUtils.pii(LOG_TAG, "aPayload  : " + a.getObject("payload"));
+        FxAccountUtils.pii(LOG_TAG, "aSignature: " + a.getString("signature"));
+        String certificate = a.getString("certificate");
+        if (certificate != null) {
+          ExtendedJSONObject c = JSONWebTokenUtils.parseCertificate(certificate);
+          FxAccountUtils.pii(LOG_TAG, "cHeader   : " + c.getObject("header"));
+          FxAccountUtils.pii(LOG_TAG, "cPayload  : " + c.getObject("payload"));
+          FxAccountUtils.pii(LOG_TAG, "cSignature: " + c.getString("signature"));
+          // Print the relevant timestamps in sorted order with labels.
+          HashMap<Long, String> map = new HashMap<Long, String>();
+          map.put(a.getObject("payload").getLong("iat"), "aiat");
+          map.put(a.getObject("payload").getLong("exp"), "aexp");
+          map.put(c.getObject("payload").getLong("iat"), "ciat");
+          map.put(c.getObject("payload").getLong("exp"), "cexp");
+          ArrayList<Long> values = new ArrayList<Long>(map.keySet());
+          Collections.sort(values);
+          for (Long value : values) {
+            FxAccountUtils.pii(LOG_TAG, map.get(value) + ": " + value);
+          }
+        } else {
+          FxAccountUtils.pii(LOG_TAG, "Could not parse certificate!");
+        }
+      } else {
+        FxAccountUtils.pii(LOG_TAG, "Could not parse assertion!");
+      }
+    } catch (Exception e) {
+      FxAccountUtils.pii(LOG_TAG, "Got exception dumping assertion debug info.");
+    }
+    return assertion;
+  }
+
+  public KeyBundle getSyncKeyBundle() throws InvalidKeyException, NoSuchAlgorithmException, UnsupportedEncodingException {
+    // TODO Document this choice for deriving from kB.
+    return FxAccountUtils.generateSyncKeyBundle(kB);
+  }
+
+  public String getClientState() {
+    if (FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+      FxAccountUtils.pii(LOG_TAG, "Client state: " + this.clientState);
+    }
+    return this.clientState;
+  }
+
+  public Cohabiting makeCohabitingState() {
+    return new Cohabiting(email, uid, sessionToken, kA, kB, keyPair);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/MigratedFromSync11.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/MigratedFromSync11.java
new file mode 100644
index 000000000..c30ac2ff7
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/MigratedFromSync11.java
@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.ExecuteDelegate;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.PasswordRequired;
+
+public class MigratedFromSync11 extends State {
+  public final String password;
+
+  public MigratedFromSync11(String email, String uid, boolean verified, String password) {
+    super(StateLabel.MigratedFromSync11, email, uid, verified);
+    // Null password is allowed.
+    this.password = password;
+  }
+
+  @Override
+  public void execute(final ExecuteDelegate delegate) {
+    delegate.handleTransition(new PasswordRequired(), this);
+  }
+
+  @Override
+  public Action getNeededAction() {
+    return Action.NeedsFinishMigrating;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Separated.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Separated.java
new file mode 100644
index 000000000..bda620df9
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/Separated.java
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.ExecuteDelegate;
+import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.PasswordRequired;
+
+
+public class Separated extends State {
+  public Separated(String email, String uid, boolean verified) {
+    super(StateLabel.Separated, email, uid, verified);
+  }
+
+  @Override
+  public void execute(final ExecuteDelegate delegate) {
+    delegate.handleTransition(new PasswordRequired(), this);
+  }
+
+  @Override
+  public Action getNeededAction() {
+    return Action.NeedsPassword;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/State.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/State.java
new file mode 100644
index 000000000..797011ec2
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/State.java
@@ -0,0 +1,72 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine.ExecuteDelegate;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.Utils;
+
+public abstract class State {
+  public static final long CURRENT_VERSION = 3L;
+
+  public enum StateLabel {
+    Engaged,
+    Cohabiting,
+    Married,
+    Separated,
+    Doghouse,
+    MigratedFromSync11,
+  }
+
+  public enum Action {
+    NeedsUpgrade,
+    NeedsPassword,
+    NeedsVerification,
+    NeedsFinishMigrating,
+    None,
+  }
+
+  protected final StateLabel stateLabel;
+  public final String email;
+  public final String uid;
+  public final boolean verified;
+
+  public State(StateLabel stateLabel, String email, String uid, boolean verified) {
+    Utils.throwIfNull(email, uid);
+    this.stateLabel = stateLabel;
+    this.email = email;
+    this.uid = uid;
+    this.verified = verified;
+  }
+
+  public StateLabel getStateLabel() {
+    return this.stateLabel;
+  }
+
+  public ExtendedJSONObject toJSONObject() {
+    ExtendedJSONObject o = new ExtendedJSONObject();
+    o.put("version", State.CURRENT_VERSION);
+    o.put("email", email);
+    o.put("uid", uid);
+    o.put("verified", verified);
+    return o;
+  }
+
+  public State makeSeparatedState() {
+    return new Separated(email, uid, verified);
+  }
+
+  public State makeDoghouseState() {
+    return new Doghouse(email, uid, verified);
+  }
+
+  public State makeMigratedFromSync11State(String password) {
+    return new MigratedFromSync11(email, uid, verified, password);
+  }
+
+  public abstract void execute(ExecuteDelegate delegate);
+
+  public abstract Action getNeededAction();
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/StateFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/StateFactory.java
new file mode 100644
index 000000000..a98f2fb27
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/StateFactory.java
@@ -0,0 +1,206 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.browserid.BrowserIDKeyPair;
+import org.mozilla.gecko.browserid.DSACryptoImplementation;
+import org.mozilla.gecko.browserid.RSACryptoImplementation;
+import org.mozilla.gecko.fxa.login.State.StateLabel;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+import org.mozilla.gecko.sync.Utils;
+
+/**
+ * Create {@link State} instances from serialized representations.
+ * <p>
+ * Version 1 recognizes 5 state labels (Engaged, Cohabiting, Married, Separated,
+ * Doghouse). In the Cohabiting and Married states, the associated key pairs are
+ * always RSA key pairs.
+ * <p>
+ * Version 2 is identical to version 1, except that in the Cohabiting and
+ * Married states, the associated keypairs are always DSA key pairs.
+ */
+public class StateFactory {
+  private static final String LOG_TAG = StateFactory.class.getSimpleName();
+
+  private static final int KEY_PAIR_SIZE_IN_BITS_V1 = 1024;
+
+  public static BrowserIDKeyPair generateKeyPair() throws NoSuchAlgorithmException {
+    // New key pairs are always DSA.
+    return DSACryptoImplementation.generateKeyPair(KEY_PAIR_SIZE_IN_BITS_V1);
+  }
+
+  protected static BrowserIDKeyPair keyPairFromJSONObjectV1(ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    // V1 key pairs are RSA.
+    return RSACryptoImplementation.fromJSONObject(o);
+  }
+
+  protected static BrowserIDKeyPair keyPairFromJSONObjectV2(ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    // V2 key pairs are DSA.
+    return DSACryptoImplementation.fromJSONObject(o);
+  }
+
+  public static State fromJSONObject(StateLabel stateLabel, ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException, NonObjectJSONException {
+    Long version = o.getLong("version");
+    if (version == null) {
+      throw new IllegalStateException("version must not be null");
+    }
+
+    final int v = version.intValue();
+    if (v == 3) {
+      // The most common case is the most recent version.
+      return fromJSONObjectV3(stateLabel, o);
+    }
+    if (v == 2) {
+      return fromJSONObjectV2(stateLabel, o);
+    }
+    if (v == 1) {
+      final State state = fromJSONObjectV1(stateLabel, o);
+      return migrateV1toV2(stateLabel, state);
+    }
+    throw new IllegalStateException("version must be in {1, 2}");
+  }
+
+  protected static State fromJSONObjectV1(StateLabel stateLabel, ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException, NonObjectJSONException {
+    switch (stateLabel) {
+    case Engaged:
+      return new Engaged(
+          o.getString("email"),
+          o.getString("uid"),
+          o.getBoolean("verified"),
+          Utils.hex2Byte(o.getString("unwrapkB")),
+          Utils.hex2Byte(o.getString("sessionToken")),
+          Utils.hex2Byte(o.getString("keyFetchToken")));
+    case Cohabiting:
+      return new Cohabiting(
+          o.getString("email"),
+          o.getString("uid"),
+          Utils.hex2Byte(o.getString("sessionToken")),
+          Utils.hex2Byte(o.getString("kA")),
+          Utils.hex2Byte(o.getString("kB")),
+          keyPairFromJSONObjectV1(o.getObject("keyPair")));
+    case Married:
+      return new Married(
+          o.getString("email"),
+          o.getString("uid"),
+          Utils.hex2Byte(o.getString("sessionToken")),
+          Utils.hex2Byte(o.getString("kA")),
+          Utils.hex2Byte(o.getString("kB")),
+          keyPairFromJSONObjectV1(o.getObject("keyPair")),
+          o.getString("certificate"));
+    case Separated:
+      return new Separated(
+          o.getString("email"),
+          o.getString("uid"),
+          o.getBoolean("verified"));
+    case Doghouse:
+      return new Doghouse(
+          o.getString("email"),
+          o.getString("uid"),
+          o.getBoolean("verified"));
+    default:
+      throw new IllegalStateException("unrecognized state label: " + stateLabel);
+    }
+  }
+
+  /**
+   * Exactly the same as {@link fromJSONObjectV1}, except that all key pairs are DSA key pairs.
+   */
+  protected static State fromJSONObjectV2(StateLabel stateLabel, ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException, NonObjectJSONException {
+    switch (stateLabel) {
+    case Cohabiting:
+      return new Cohabiting(
+          o.getString("email"),
+          o.getString("uid"),
+          Utils.hex2Byte(o.getString("sessionToken")),
+          Utils.hex2Byte(o.getString("kA")),
+          Utils.hex2Byte(o.getString("kB")),
+          keyPairFromJSONObjectV2(o.getObject("keyPair")));
+    case Married:
+      return new Married(
+          o.getString("email"),
+          o.getString("uid"),
+          Utils.hex2Byte(o.getString("sessionToken")),
+          Utils.hex2Byte(o.getString("kA")),
+          Utils.hex2Byte(o.getString("kB")),
+          keyPairFromJSONObjectV2(o.getObject("keyPair")),
+          o.getString("certificate"));
+    default:
+      return fromJSONObjectV1(stateLabel, o);
+    }
+  }
+
+  /**
+   * Exactly the same as {@link fromJSONObjectV2}, except that there's a new
+   * MigratedFromSyncV11 state.
+   */
+  protected static State fromJSONObjectV3(StateLabel stateLabel, ExtendedJSONObject o) throws InvalidKeySpecException, NoSuchAlgorithmException, NonObjectJSONException {
+    switch (stateLabel) {
+    case MigratedFromSync11:
+      return new MigratedFromSync11(
+          o.getString("email"),
+          o.getString("uid"),
+          o.getBoolean("verified"),
+          o.getString("password"));
+    default:
+      return fromJSONObjectV2(stateLabel, o);
+    }
+  }
+
+  protected static void logMigration(State from, State to) {
+    if (!FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+      return;
+    }
+    try {
+      FxAccountUtils.pii(LOG_TAG, "V1 persisted state is: " + from.toJSONObject().toJSONString());
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Error producing JSON representation of V1 state.", e);
+    }
+    FxAccountUtils.pii(LOG_TAG, "Generated new V2 state: " + to.toJSONObject().toJSONString());
+  }
+
+  protected static State migrateV1toV2(StateLabel stateLabel, State state) throws NoSuchAlgorithmException {
+    if (state == null) {
+      // This should never happen, but let's be careful.
+      Logger.error(LOG_TAG, "Got null state in migrateV1toV2; returning null.");
+      return state;
+    }
+
+    Logger.info(LOG_TAG, "Migrating V1 persisted State to V2; stateLabel: " + stateLabel);
+
+    // In V1, we use an RSA keyPair. In V2, we use a DSA keyPair. Only
+    // Cohabiting and Married states have a persisted keyPair at all; all
+    // other states need no conversion at all.
+    switch (stateLabel) {
+    case Cohabiting: {
+      // In the Cohabiting state, we can just generate a new key pair and move on.
+      final Cohabiting cohabiting = (Cohabiting) state;
+      final BrowserIDKeyPair keyPair = generateKeyPair();
+      final State migrated = new Cohabiting(cohabiting.email, cohabiting.uid, cohabiting.sessionToken, cohabiting.kA, cohabiting.kB, keyPair);
+      logMigration(cohabiting, migrated);
+      return migrated;
+    }
+    case Married: {
+      // In the Married state, we cannot only change the key pair: the stored
+      // certificate signs the public key of the now obsolete key pair. We
+      // regress to the Cohabiting state; the next time we sync, we should
+      // advance back to Married.
+      final Married married = (Married) state;
+      final BrowserIDKeyPair keyPair = generateKeyPair();
+      final State migrated = new Cohabiting(married.email, married.uid, married.sessionToken, married.kA, married.kB, keyPair);
+      logMigration(married, migrated);
+      return migrated;
+    }
+    default:
+      // Otherwise, V1 and V2 states are identical.
+      return state;
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/TokensAndKeysState.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/TokensAndKeysState.java
new file mode 100644
index 000000000..b5121a4d4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/login/TokensAndKeysState.java
@@ -0,0 +1,45 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.login;
+
+import org.mozilla.gecko.browserid.BrowserIDKeyPair;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.Utils;
+
+public abstract class TokensAndKeysState extends State {
+  protected final byte[] sessionToken;
+  protected final byte[] kA;
+  protected final byte[] kB;
+  protected final BrowserIDKeyPair keyPair;
+
+  public TokensAndKeysState(StateLabel stateLabel, String email, String uid, byte[] sessionToken, byte[] kA, byte[] kB, BrowserIDKeyPair keyPair) {
+    super(stateLabel, email, uid, true);
+    Utils.throwIfNull(sessionToken, kA, kB, keyPair);
+    this.sessionToken = sessionToken;
+    this.kA = kA;
+    this.kB = kB;
+    this.keyPair = keyPair;
+  }
+
+  @Override
+  public ExtendedJSONObject toJSONObject() {
+    ExtendedJSONObject o = super.toJSONObject();
+    // Fields are non-null by constructor.
+    o.put("sessionToken", Utils.byte2Hex(sessionToken));
+    o.put("kA", Utils.byte2Hex(kA));
+    o.put("kB", Utils.byte2Hex(kB));
+    o.put("keyPair", keyPair.toJSONObject());
+    return o;
+  }
+
+  public byte[] getSessionToken() {
+    return sessionToken;
+  }
+
+  @Override
+  public Action getNeededAction() {
+    return Action.None;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/receivers/FxAccountDeletedService.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/receivers/FxAccountDeletedService.java
new file mode 100644
index 000000000..60a63a5e1
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/receivers/FxAccountDeletedService.java
@@ -0,0 +1,154 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.receivers;
+
+import android.app.IntentService;
+import android.content.Context;
+import android.content.Intent;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountAbstractClient;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountAbstractClientException.FxAccountAbstractClientRemoteException;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountOAuthClient10;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.fxa.sync.FxAccountNotificationManager;
+import org.mozilla.gecko.fxa.sync.FxAccountSyncAdapter;
+import org.mozilla.gecko.sync.repositories.android.ClientsDatabase;
+import org.mozilla.gecko.sync.repositories.android.FennecTabsRepository;
+
+import java.util.concurrent.Executor;
+
+/**
+ * A background service to clean up after a Firefox Account is deleted.
+ * <p>
+ * Note that we specifically handle deleting the pickle file using a Service and a
+ * BroadcastReceiver, rather than a background thread, to allow channels sharing a Firefox account
+ * to delete their respective pickle files (since, if one remains, the account will be restored
+ * when that channel is used).
+ */
+public class FxAccountDeletedService extends IntentService {
+  public static final String LOG_TAG = FxAccountDeletedService.class.getSimpleName();
+
+  public FxAccountDeletedService() {
+    super(LOG_TAG);
+  }
+
+  @Override
+  protected void onHandleIntent(final Intent intent) {
+    // We have an in-memory accounts cache which we use for a variety of tasks; it needs to be cleared.
+    // It should be fine to invalidate it before doing anything else, as the tasks below do not rely
+    // on this data.
+    AndroidFxAccount.invalidateCaches();
+
+    // Intent can, in theory, be null. Bug 1025937.
+    if (intent == null) {
+      Logger.debug(LOG_TAG, "Short-circuiting on null intent.");
+      return;
+    }
+
+    final Context context = this;
+
+    long intentVersion = intent.getLongExtra(
+        FxAccountConstants.ACCOUNT_DELETED_INTENT_VERSION_KEY, 0);
+    long expectedVersion = FxAccountConstants.ACCOUNT_DELETED_INTENT_VERSION;
+    if (intentVersion != expectedVersion) {
+      Logger.warn(LOG_TAG, "Intent malformed: version " + intentVersion + " given but " +
+          "version " + expectedVersion + "expected. Not cleaning up after deleted Account.");
+      return;
+    }
+
+    // Android Account name, not Sync encoded account name.
+    final String accountName = intent.getStringExtra(
+        FxAccountConstants.ACCOUNT_DELETED_INTENT_ACCOUNT_KEY);
+    if (accountName == null) {
+      Logger.warn(LOG_TAG, "Intent malformed: no account name given. Not cleaning up after " +
+          "deleted Account.");
+      return;
+    }
+
+
+    // Fire up gecko and unsubscribe push
+    final Intent geckoIntent = new Intent();
+    geckoIntent.setAction("create-services");
+    geckoIntent.setClassName(context, "org.mozilla.gecko.GeckoService");
+    geckoIntent.putExtra("category", "android-push-service");
+    geckoIntent.putExtra("data", "android-fxa-unsubscribe");
+    final AndroidFxAccount fxAccount = AndroidFxAccount.fromContext(context);
+    geckoIntent.putExtra("org.mozilla.gecko.intent.PROFILE_NAME",
+            intent.getStringExtra(FxAccountConstants.ACCOUNT_DELETED_INTENT_ACCOUNT_PROFILE));
+    context.startService(geckoIntent);
+
+    // Delete client database and non-local tabs.
+    Logger.info(LOG_TAG, "Deleting the entire Fennec clients database and non-local tabs");
+    FennecTabsRepository.deleteNonLocalClientsAndTabs(context);
+
+
+    // Clear Firefox Sync client tables.
+    try {
+      Logger.info(LOG_TAG, "Deleting the Firefox Sync clients database.");
+      ClientsDatabase db = null;
+      try {
+        db = new ClientsDatabase(context);
+        db.wipeClientsTable();
+        db.wipeCommandsTable();
+      } finally {
+        if (db != null) {
+          db.close();
+        }
+      }
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception deleting the Firefox Sync clients database; ignoring.", e);
+    }
+
+    // Remove any displayed notifications.
+    new FxAccountNotificationManager(FxAccountSyncAdapter.NOTIFICATION_ID).clear(context);
+
+    // Bug 1147275: Delete cached oauth tokens. There's no way to query all
+    // oauth tokens from Android, so this is tricky to do comprehensively. We
+    // can query, individually, for specific oauth tokens to delete, however.
+    final String oauthServerURI = intent.getStringExtra(FxAccountConstants.ACCOUNT_OAUTH_SERVICE_ENDPOINT_KEY);
+    final String[] tokens = intent.getStringArrayExtra(FxAccountConstants.ACCOUNT_DELETED_INTENT_ACCOUNT_AUTH_TOKENS);
+    if (oauthServerURI != null && tokens != null) {
+      final Executor directExecutor = new Executor() {
+        @Override
+        public void execute(Runnable runnable) {
+          runnable.run();
+        }
+      };
+
+      final FxAccountOAuthClient10 oauthClient = new FxAccountOAuthClient10(oauthServerURI, directExecutor);
+
+      for (String token : tokens) {
+        if (token == null) {
+          Logger.error(LOG_TAG, "Cached OAuth token is null; should never happen.  Ignoring.");
+          continue;
+        }
+        try {
+          oauthClient.deleteToken(token, new FxAccountAbstractClient.RequestDelegate<Void>() {
+            @Override
+            public void handleSuccess(Void result) {
+              Logger.info(LOG_TAG, "Successfully deleted cached OAuth token.");
+            }
+
+            @Override
+            public void handleError(Exception e) {
+              Logger.error(LOG_TAG, "Failed to delete cached OAuth token; ignoring.", e);
+            }
+
+            @Override
+            public void handleFailure(FxAccountAbstractClientRemoteException e) {
+              Logger.error(LOG_TAG, "Exception during cached OAuth token deletion; ignoring.", e);
+            }
+          });
+        } catch (Exception e) {
+          Logger.error(LOG_TAG, "Exception during cached OAuth token deletion; ignoring.", e);
+        }
+      }
+    } else {
+      Logger.error(LOG_TAG, "Cached OAuth server URI is null or cached OAuth tokens are null; ignoring.");
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/receivers/FxAccountUpgradeReceiver.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/receivers/FxAccountUpgradeReceiver.java
new file mode 100644
index 000000000..ad81e0488
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/receivers/FxAccountUpgradeReceiver.java
@@ -0,0 +1,133 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.receivers;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.fxa.FirefoxAccounts;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.fxa.login.State.StateLabel;
+import org.mozilla.gecko.sync.Utils;
+
+import android.accounts.Account;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+
+/**
+ * A receiver that takes action when our Android package is upgraded (replaced).
+ */
+public class FxAccountUpgradeReceiver extends BroadcastReceiver {
+  private static final String LOG_TAG = FxAccountUpgradeReceiver.class.getSimpleName();
+
+  /**
+   * Produce a list of Runnable instances to be executed sequentially on
+   * upgrade.
+   * <p>
+   * Each Runnable will be executed sequentially on a background thread. Any
+   * unchecked Exception thrown will be caught and ignored.
+   *
+   * @param context Android context.
+   * @return list of Runnable instances.
+   */
+  protected List<Runnable> onUpgradeRunnables(Context context) {
+    List<Runnable> runnables = new LinkedList<Runnable>();
+    runnables.add(new MaybeUnpickleRunnable(context));
+    // Recovering accounts that are in the Doghouse should happen *after* we
+    // unpickle any accounts saved to disk.
+    runnables.add(new AdvanceFromDoghouseRunnable(context));
+    return runnables;
+  }
+
+  @Override
+  public void onReceive(final Context context, Intent intent) {
+    Logger.setThreadLogTag(FxAccountConstants.GLOBAL_LOG_TAG);
+    Logger.info(LOG_TAG, "Upgrade broadcast received.");
+
+    // Iterate Runnable instances one at a time.
+    final Executor executor = Executors.newSingleThreadExecutor();
+    for (final Runnable runnable : onUpgradeRunnables(context)) {
+      executor.execute(new Runnable() {
+        @Override
+        public void run() {
+          try {
+            runnable.run();
+          } catch (Exception e) {
+            // We really don't want to throw on a background thread, so we
+            // catch, log, and move on.
+            Logger.error(LOG_TAG, "Got exception executing background upgrade Runnable; ignoring.", e);
+          }
+        }
+      });
+    }
+  }
+
+  /**
+   * A Runnable that tries to unpickle any pickled Firefox Accounts.
+   */
+  protected static class MaybeUnpickleRunnable implements Runnable {
+    protected final Context context;
+
+    public MaybeUnpickleRunnable(Context context) {
+      this.context = context;
+    }
+
+    @Override
+    public void run() {
+      // Querying the accounts will unpickle any pickled Firefox Account.
+      Logger.info(LOG_TAG, "Trying to unpickle any pickled Firefox Account.");
+      FirefoxAccounts.getFirefoxAccounts(context);
+    }
+  }
+
+  /**
+   * A Runnable that tries to advance existing Firefox Accounts that are in the
+   * Doghouse state to the Separated state.
+   * <p>
+   * This is our main deprecation-and-upgrade mechanism: in some way, the
+   * Account gets moved to the Doghouse state. If possible, an upgraded version
+   * of the package advances to Separated, prompting the user to re-connect the
+   * Account.
+   */
+  protected static class AdvanceFromDoghouseRunnable implements Runnable {
+    protected final Context context;
+
+    public AdvanceFromDoghouseRunnable(Context context) {
+      this.context = context;
+    }
+
+    @Override
+    public void run() {
+      final Account[] accounts = FirefoxAccounts.getFirefoxAccounts(context);
+      Logger.info(LOG_TAG, "Trying to advance " + accounts.length + " existing Firefox Accounts from the Doghouse to Separated (if necessary).");
+      for (Account account : accounts) {
+        try {
+          final AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+          // For great debugging.
+          if (FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+            fxAccount.dump();
+          }
+          State state = fxAccount.getState();
+          if (state == null || state.getStateLabel() != StateLabel.Doghouse) {
+            Logger.debug(LOG_TAG, "Account named like " + Utils.obfuscateEmail(account.name) + " is not in the Doghouse; skipping.");
+            continue;
+          }
+          Logger.debug(LOG_TAG, "Account named like " + Utils.obfuscateEmail(account.name) + " is in the Doghouse; advancing to Separated.");
+          fxAccount.setState(state.makeSeparatedState());
+        } catch (Exception e) {
+          Logger.warn(LOG_TAG, "Got exception trying to advance account named like " + Utils.obfuscateEmail(account.name) +
+              " from Doghouse to Separated state; ignoring.", e);
+        }
+      }
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountNotificationManager.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountNotificationManager.java
new file mode 100644
index 000000000..b44da76fc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountNotificationManager.java
@@ -0,0 +1,114 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.sync;
+
+import android.app.NotificationManager;
+import android.app.PendingIntent;
+import android.content.Context;
+import android.content.Intent;
+import android.support.v4.app.NotificationCompat;
+import android.support.v4.app.NotificationCompat.Builder;
+import org.mozilla.gecko.Locales;
+import org.mozilla.gecko.R;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.common.telemetry.TelemetryWrapper;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.fxa.activities.FxAccountWebFlowActivity;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.fxa.login.State.Action;
+import org.mozilla.gecko.sync.telemetry.TelemetryContract;
+
+/**
+ * Abstraction that manages notifications shown or hidden for a Firefox Account.
+ * <p>
+ * In future, we anticipate this tracking things like:
+ * <ul>
+ * <li>new engines to offer to Sync;</li>
+ * <li>service interruption updates;</li>
+ * <li>messages from other clients.</li>
+ * </ul>
+ */
+public class FxAccountNotificationManager {
+  private static final String LOG_TAG = FxAccountNotificationManager.class.getSimpleName();
+
+  protected final int notificationId;
+
+  // We're lazy about updating our locale info, because most syncs don't notify.
+  private volatile boolean localeUpdated;
+
+  public FxAccountNotificationManager(int notificationId) {
+    this.notificationId = notificationId;
+  }
+
+  /**
+   * Remove all Firefox Account related notifications from the notification manager.
+   *
+   * @param context
+   *          Android context.
+   */
+  public void clear(Context context) {
+    final NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+    notificationManager.cancel(notificationId);
+  }
+
+  /**
+   * Reflect new Firefox Account state to the notification manager: show or hide
+   * notifications reflecting the state of a Firefox Account.
+   *
+   * @param context
+   *          Android context.
+   * @param fxAccount
+   *          Firefox Account to reflect to the notification manager.
+   */
+  public void update(Context context, AndroidFxAccount fxAccount) {
+    final NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+
+    final State state = fxAccount.getState();
+    final Action action = state.getNeededAction();
+    if (action == Action.None) {
+      Logger.info(LOG_TAG, "State " + state.getStateLabel() + " needs no action; cancelling any existing notification.");
+      notificationManager.cancel(notificationId);
+      return;
+    }
+
+    if (!localeUpdated) {
+      localeUpdated = true;
+      Locales.getLocaleManager().getAndApplyPersistedLocale(context);
+    }
+
+    final String title;
+    final String text;
+    final Intent notificationIntent;
+    if (action == Action.NeedsFinishMigrating) {
+      TelemetryWrapper.addToHistogram(TelemetryContract.SYNC11_MIGRATION_NOTIFICATIONS_OFFERED, 1);
+
+      title = context.getResources().getString(R.string.fxaccount_sync_finish_migrating_notification_title);
+      text = context.getResources().getString(R.string.fxaccount_sync_finish_migrating_notification_text, state.email);
+      notificationIntent = new Intent(FxAccountConstants.ACTION_FXA_FINISH_MIGRATING);
+    } else {
+      title = context.getResources().getString(R.string.fxaccount_sync_sign_in_error_notification_title);
+      text = context.getResources().getString(R.string.fxaccount_sync_sign_in_error_notification_text, state.email);
+      notificationIntent = new Intent(FxAccountConstants.ACTION_FXA_STATUS);
+    }
+
+    notificationIntent.putExtra(FxAccountWebFlowActivity.EXTRA_ENDPOINT, FxAccountConstants.ENDPOINT_NOTIFICATION);
+
+    Logger.info(LOG_TAG, "State " + state.getStateLabel() + " needs action; offering notification with title: " + title);
+    FxAccountUtils.pii(LOG_TAG, "And text: " + text);
+
+    final PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, notificationIntent, 0);
+
+    final Builder builder = new NotificationCompat.Builder(context);
+    builder
+    .setContentTitle(title)
+    .setContentText(text)
+    .setSmallIcon(R.drawable.ic_status_logo)
+    .setAutoCancel(true)
+    .setContentIntent(pendingIntent);
+    notificationManager.notify(notificationId, builder.build());
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountProfileService.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountProfileService.java
new file mode 100644
index 000000000..7f03eff1c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountProfileService.java
@@ -0,0 +1,107 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.sync;
+
+import android.accounts.AccountManager;
+import android.app.Activity;
+import android.app.IntentService;
+import android.content.Intent;
+import android.os.Bundle;
+import android.os.ResultReceiver;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountAbstractClient;
+import org.mozilla.gecko.background.fxa.oauth.FxAccountAbstractClientException;
+import org.mozilla.gecko.background.fxa.profile.FxAccountProfileClient10;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+
+public class FxAccountProfileService extends IntentService {
+  private static final String LOG_TAG = "FxAccountProfileService";
+  private static final Executor EXECUTOR_SERVICE = Executors.newSingleThreadExecutor();
+  public static final String KEY_AUTH_TOKEN = "auth_token";
+  public static final String KEY_PROFILE_SERVER_URI = "profileServerURI";
+  public static final String KEY_RESULT_RECEIVER = "resultReceiver";
+  public static final String KEY_RESULT_STRING = "RESULT_STRING";
+
+  public FxAccountProfileService() {
+    super("FxAccountProfileService");
+  }
+
+  @Override
+  protected void onHandleIntent(Intent intent) {
+    final String authToken = intent.getStringExtra(KEY_AUTH_TOKEN);
+    final String profileServerURI = intent.getStringExtra(KEY_PROFILE_SERVER_URI);
+    final ResultReceiver resultReceiver = intent.getParcelableExtra(KEY_RESULT_RECEIVER);
+
+    if (resultReceiver == null) {
+      Logger.warn(LOG_TAG, "Result receiver must not be null; ignoring intent.");
+      return;
+    }
+
+    if (authToken == null || authToken.length() == 0) {
+      Logger.warn(LOG_TAG, "Invalid Auth Token");
+      sendResult("Invalid Auth Token", resultReceiver, Activity.RESULT_CANCELED);
+      return;
+    }
+
+    if (profileServerURI == null || profileServerURI.length() == 0) {
+      Logger.warn(LOG_TAG, "Invalid profile Server Endpoint");
+      sendResult("Invalid profile Server Endpoint", resultReceiver, Activity.RESULT_CANCELED);
+      return;
+    }
+
+    // This delegate fetches the profile avatar json.
+    FxAccountProfileClient10.RequestDelegate<ExtendedJSONObject> delegate = new FxAccountAbstractClient.RequestDelegate<ExtendedJSONObject>() {
+      @Override
+      public void handleError(Exception e) {
+        Logger.error(LOG_TAG, "Error fetching Account profile.", e);
+        sendResult("Error fetching Account profile.", resultReceiver, Activity.RESULT_CANCELED);
+      }
+
+      @Override
+      public void handleFailure(FxAccountAbstractClientException.FxAccountAbstractClientRemoteException e) {
+        Logger.warn(LOG_TAG, "Failed to fetch Account profile.", e);
+
+        if (e.isInvalidAuthentication()) {
+          // The profile server rejected the cached oauth token! Invalidate it.
+          // A new token will be generated upon next request.
+          Logger.info(LOG_TAG, "Invalidating oauth token after 401!");
+          AccountManager.get(FxAccountProfileService.this).invalidateAuthToken(FxAccountConstants.ACCOUNT_TYPE, authToken);
+        }
+
+        sendResult("Failed to fetch Account profile.", resultReceiver, Activity.RESULT_CANCELED);
+      }
+
+      @Override
+      public void handleSuccess(ExtendedJSONObject result) {
+        if (result != null){
+          FxAccountUtils.pii(LOG_TAG, "Profile server return profile: " + result.toJSONString());
+          sendResult(result.toJSONString(), resultReceiver, Activity.RESULT_OK);
+        }
+      }
+    };
+
+    FxAccountProfileClient10 client = new FxAccountProfileClient10(profileServerURI, EXECUTOR_SERVICE);
+    try {
+      client.profile(authToken, delegate);
+    } catch (Exception e) {
+      Logger.error(LOG_TAG, "Got exception fetching profile.", e);
+      delegate.handleError(e);
+    }
+  }
+
+  private void sendResult(final String result, final ResultReceiver resultReceiver, final int code) {
+    if (resultReceiver != null) {
+      final Bundle bundle = new Bundle();
+      bundle.putString(KEY_RESULT_STRING, result);
+      resultReceiver.send(code, bundle);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSchedulePolicy.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSchedulePolicy.java
new file mode 100644
index 000000000..708686e72
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSchedulePolicy.java
@@ -0,0 +1,178 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.sync;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.fxa.login.State.Action;
+import org.mozilla.gecko.sync.BackoffHandler;
+
+import android.accounts.Account;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.os.Bundle;
+
+public class FxAccountSchedulePolicy implements SchedulePolicy {
+  private static final String LOG_TAG = "FxAccountSchedulePolicy";
+
+  // Our poll intervals are used to trigger automatic background syncs
+  // in the absence of user activity.
+  //
+  // We also receive sync requests as a result of network tickles, so
+  // these intervals are long, with the exception of the rapid polling
+  // while we wait for verification: if we're waiting for the user to
+  // click on a verification link, we sync very often in order to detect
+  // a change in state.
+  //
+  // In the case of unverified -> unverified (no transition), this should be
+  // very close to a single HTTP request (with the SyncAdapter overhead, of
+  // course, but that's not wildly different from alarm manager overhead).
+  //
+  // The /account/status endpoint is HAWK authed by sessionToken, so we still
+  // have to do some crypto no matter what.
+
+  // TODO: only do this for a while...
+  public static final long POLL_INTERVAL_PENDING_VERIFICATION = 60;         // 1 minute.
+
+  // If we're in some kind of error state, there's no point trying often.
+  // This is not the same as a server-imposed backoff, which will be
+  // reflected dynamically.
+  public static final long POLL_INTERVAL_ERROR_STATE_SEC = 24 * 60 * 60;    // 24 hours.
+
+  // If we're the only device, just sync once or twice a day in case that
+  // changes.
+  public static final long POLL_INTERVAL_SINGLE_DEVICE_SEC = 18 * 60 * 60;  // 18 hours.
+
+  // And if we know there are other devices, let's sync often enough that
+  // we'll be more likely to be caught up (even if not completely) by the
+  // time you next use this device. This is also achieved via Android's
+  // network tickles.
+  public static final long POLL_INTERVAL_MULTI_DEVICE_SEC = 12 * 60 * 60;   // 12 hours.
+
+  // This is used solely as an optimization for backoff handling, so it's not
+  // persisted.
+  private static volatile long POLL_INTERVAL_CURRENT_SEC = POLL_INTERVAL_SINGLE_DEVICE_SEC;
+
+  // Never sync more frequently than this, unless forced.
+  // This is to avoid overly-frequent syncs during active browsing.
+  public static final long RATE_LIMIT_FUNDAMENTAL_SEC = 90;                 // 90 seconds.
+
+  /**
+   * We are prompted to sync by several inputs:
+   * * Periodic syncs that we schedule at long intervals. See the POLL constants.
+   * * Network-tickle-based syncs that Android starts.
+   * * Upload-only syncs that are caused by local database writes.
+   *
+   * We rate-limit periodic and network-sourced events with this constant.
+   * We rate limit <b>both</b> with {@link FxAccountSchedulePolicy#RATE_LIMIT_FUNDAMENTAL_SEC}.
+   */
+  public static final long RATE_LIMIT_BACKGROUND_SEC = 60 * 60;             // 1 hour.
+
+  private final AndroidFxAccount account;
+  private final Context context;
+
+  public FxAccountSchedulePolicy(Context context, AndroidFxAccount account) {
+    this.account = account;
+    this.context = context;
+  }
+
+  /**
+   * Return a millisecond timestamp in the future, offset from the current
+   * time by the provided amount.
+   * @param millis the duration by which to delay
+   * @return a timestamp.
+   */
+  private static long delay(long millis) {
+    return System.currentTimeMillis() + millis;
+  }
+
+  /**
+   * Updates the existing system periodic sync interval to the specified duration.
+   *
+   * @param intervalSeconds the requested period, which Android will vary by up to 4%.
+   */
+  protected void requestPeriodicSync(final long intervalSeconds) {
+    final String authority = BrowserContract.AUTHORITY;
+    final Account account = this.account.getAndroidAccount();
+    this.context.getContentResolver();
+    Logger.info(LOG_TAG, "Scheduling periodic sync for " + intervalSeconds + ".");
+    ContentResolver.addPeriodicSync(account, authority, Bundle.EMPTY, intervalSeconds);
+    POLL_INTERVAL_CURRENT_SEC = intervalSeconds;
+  }
+
+  @Override
+  public void onSuccessfulSync(int otherClientsCount) {
+    this.account.setLastSyncedTimestamp(System.currentTimeMillis());
+    // This undoes the change made in observeBackoffMillis -- once we hit backoff we'll
+    // periodically sync at the backoff duration, but as soon as we succeed we'll switch
+    // into the client-count-dependent interval.
+    long interval = (otherClientsCount > 0) ? POLL_INTERVAL_MULTI_DEVICE_SEC : POLL_INTERVAL_SINGLE_DEVICE_SEC;
+    requestPeriodicSync(interval);
+  }
+
+  @Override
+  public void onHandleFinal(Action needed) {
+    switch (needed) {
+    case NeedsPassword:
+    case NeedsUpgrade:
+    case NeedsFinishMigrating:
+      requestPeriodicSync(POLL_INTERVAL_ERROR_STATE_SEC);
+      break;
+    case NeedsVerification:
+      requestPeriodicSync(POLL_INTERVAL_PENDING_VERIFICATION);
+      break;
+    case None:
+      // No action needed: we'll set the periodic sync interval
+      // when the sync finishes, via the SessionCallback.
+      break;
+    }
+  }
+
+  @Override
+  public void onUpgradeRequired() {
+    // TODO: this shouldn't occur in FxA, but when we upgrade we
+    // need to reduce the interval again.
+    requestPeriodicSync(POLL_INTERVAL_ERROR_STATE_SEC);
+  }
+
+  @Override
+  public void onUnauthorized() {
+    // TODO: this shouldn't occur in FxA, but when we fix our credentials
+    // we need to reduce the interval again.
+    requestPeriodicSync(POLL_INTERVAL_ERROR_STATE_SEC);
+  }
+
+  @Override
+  public void configureBackoffMillisOnBackoff(BackoffHandler backoffHandler, long backoffMillis, boolean onlyExtend) {
+    if (onlyExtend) {
+      backoffHandler.extendEarliestNextRequest(delay(backoffMillis));
+    } else {
+      backoffHandler.setEarliestNextRequest(delay(backoffMillis));
+    }
+
+    // Yes, we might be part-way through the interval, in which case the backoff
+    // code will do its job. But we certainly don't want to reduce the interval
+    // if we're given a small backoff instruction.
+    // We'll reset the poll interval next time we sync without a backoff instruction.
+    if (backoffMillis > (POLL_INTERVAL_CURRENT_SEC * 1000)) {
+      // Slightly inflate the backoff duration to ensure that a fuzzed
+      // periodic sync doesn't occur before our backoff has passed. Android
+      // 19+ default to a 4% fuzz factor.
+      requestPeriodicSync((long) Math.ceil((1.05 * backoffMillis) / 1000));
+    }
+  }
+
+  /**
+   * Accepts two {@link BackoffHandler} instances as input. These are used
+   * respectively to track fundamental rate limiting, and to separately
+   * rate-limit periodic and network-tickled syncs.
+   */
+  @Override
+  public void configureBackoffMillisBeforeSyncing(BackoffHandler fundamentalRateHandler, BackoffHandler backgroundRateHandler) {
+    fundamentalRateHandler.setEarliestNextRequest(delay(RATE_LIMIT_FUNDAMENTAL_SEC * 1000));
+    backgroundRateHandler.setEarliestNextRequest(delay(RATE_LIMIT_BACKGROUND_SEC * 1000));
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncAdapter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncAdapter.java
new file mode 100644
index 000000000..30990cf7f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncAdapter.java
@@ -0,0 +1,568 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.sync;
+
+import android.accounts.Account;
+import android.content.AbstractThreadedSyncAdapter;
+import android.content.ContentProviderClient;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.content.SyncResult;
+import android.os.Bundle;
+import android.os.SystemClock;
+import android.text.TextUtils;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.common.telemetry.TelemetryWrapper;
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.background.fxa.SkewHandler;
+import org.mozilla.gecko.browserid.JSONWebTokenUtils;
+import org.mozilla.gecko.fxa.FirefoxAccounts;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.fxa.FxAccountDeviceRegistrator;
+import org.mozilla.gecko.fxa.authenticator.AccountPickler;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.fxa.authenticator.FxADefaultLoginStateMachineDelegate;
+import org.mozilla.gecko.fxa.authenticator.FxAccountAuthenticator;
+import org.mozilla.gecko.fxa.login.FxAccountLoginStateMachine;
+import org.mozilla.gecko.fxa.login.Married;
+import org.mozilla.gecko.fxa.login.State;
+import org.mozilla.gecko.fxa.login.State.StateLabel;
+import org.mozilla.gecko.fxa.sync.FxAccountSyncDelegate.Result;
+import org.mozilla.gecko.sync.BackoffHandler;
+import org.mozilla.gecko.sync.GlobalSession;
+import org.mozilla.gecko.sync.PrefsBackoffHandler;
+import org.mozilla.gecko.sync.SharedPreferencesClientsDataDelegate;
+import org.mozilla.gecko.sync.SyncConfiguration;
+import org.mozilla.gecko.sync.ThreadPool;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.delegates.GlobalSessionCallback;
+import org.mozilla.gecko.sync.delegates.ClientsDataDelegate;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.HawkAuthHeaderProvider;
+import org.mozilla.gecko.sync.stage.GlobalSyncStage.Stage;
+import org.mozilla.gecko.sync.telemetry.TelemetryContract;
+import org.mozilla.gecko.tokenserver.TokenServerClient;
+import org.mozilla.gecko.tokenserver.TokenServerClientDelegate;
+import org.mozilla.gecko.tokenserver.TokenServerException;
+import org.mozilla.gecko.tokenserver.TokenServerToken;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.LinkedBlockingQueue;
+
+public class FxAccountSyncAdapter extends AbstractThreadedSyncAdapter {
+  private static final String LOG_TAG = FxAccountSyncAdapter.class.getSimpleName();
+
+  public static final int NOTIFICATION_ID = LOG_TAG.hashCode();
+
+  // Tracks the last seen storage hostname for backoff purposes.
+  private static final String PREF_BACKOFF_STORAGE_HOST = "backoffStorageHost";
+
+  // Used to do cheap in-memory rate limiting. Don't sync again if we
+  // successfully synced within this duration.
+  private static final int MINIMUM_SYNC_DELAY_MILLIS = 15 * 1000;        // 15 seconds.
+  private volatile long lastSyncRealtimeMillis;
+
+  protected final ExecutorService executor;
+  protected final FxAccountNotificationManager notificationManager;
+
+  public FxAccountSyncAdapter(Context context, boolean autoInitialize) {
+    super(context, autoInitialize);
+    this.executor = Executors.newSingleThreadExecutor();
+    this.notificationManager = new FxAccountNotificationManager(NOTIFICATION_ID);
+  }
+
+  protected static class SyncDelegate extends FxAccountSyncDelegate {
+    @Override
+    public void handleSuccess() {
+      Logger.info(LOG_TAG, "Sync succeeded.");
+      super.handleSuccess();
+      TelemetryWrapper.addToHistogram(TelemetryContract.SYNC_COMPLETED, 1);
+    }
+
+    @Override
+    public void handleError(Exception e) {
+      Logger.error(LOG_TAG, "Got exception syncing.", e);
+      super.handleError(e);
+      TelemetryWrapper.addToHistogram(TelemetryContract.SYNC_FAILED, 1);
+    }
+
+    @Override
+    public void handleCannotSync(State finalState) {
+      Logger.warn(LOG_TAG, "Cannot sync from state: " + finalState.getStateLabel());
+      super.handleCannotSync(finalState);
+    }
+
+    @Override
+    public void postponeSync(long millis) {
+      if (millis <= 0) {
+        Logger.debug(LOG_TAG, "Asked to postpone sync, but zero delay.");
+      }
+      super.postponeSync(millis);
+    }
+
+    @Override
+    public void rejectSync() {
+      super.rejectSync();
+    }
+
+    protected final Collection<String> stageNamesToSync;
+
+    public SyncDelegate(BlockingQueue<Result> latch, SyncResult syncResult, AndroidFxAccount fxAccount, Collection<String> stageNamesToSync) {
+      super(latch, syncResult);
+      this.stageNamesToSync = Collections.unmodifiableCollection(stageNamesToSync);
+    }
+
+    public Collection<String> getStageNamesToSync() {
+      return this.stageNamesToSync;
+    }
+  }
+
+  protected static class SessionCallback implements GlobalSessionCallback {
+    protected final SyncDelegate syncDelegate;
+    protected final SchedulePolicy schedulePolicy;
+    protected volatile BackoffHandler storageBackoffHandler;
+
+    public SessionCallback(SyncDelegate syncDelegate, SchedulePolicy schedulePolicy) {
+      this.syncDelegate = syncDelegate;
+      this.schedulePolicy = schedulePolicy;
+    }
+
+    public void setBackoffHandler(BackoffHandler backoffHandler) {
+      this.storageBackoffHandler = backoffHandler;
+    }
+
+    @Override
+    public boolean shouldBackOffStorage() {
+      return storageBackoffHandler.delayMilliseconds() > 0;
+    }
+
+    @Override
+    public void requestBackoff(long backoffMillis) {
+      final boolean onlyExtend = true;      // Because we trust what the storage server says.
+      schedulePolicy.configureBackoffMillisOnBackoff(storageBackoffHandler, backoffMillis, onlyExtend);
+    }
+
+    @Override
+    public void informUpgradeRequiredResponse(GlobalSession session) {
+      schedulePolicy.onUpgradeRequired();
+    }
+
+    @Override
+    public void informUnauthorizedResponse(GlobalSession globalSession, URI oldClusterURL) {
+      schedulePolicy.onUnauthorized();
+    }
+
+    @Override
+    public void informMigrated(GlobalSession globalSession) {
+      // It's not possible to migrate a Firefox Account to another Account type
+      // yet. Yell loudly but otherwise ignore.
+      Logger.error(LOG_TAG,
+          "Firefox Account informMigrated called, but it's not yet possible to migrate.  " +
+          "Ignoring even though something is terribly wrong.");
+    }
+
+    @Override
+    public void handleStageCompleted(Stage currentState, GlobalSession globalSession) {
+    }
+
+    @Override
+    public void handleSuccess(GlobalSession globalSession) {
+      Logger.info(LOG_TAG, "Global session succeeded.");
+
+      // Get the number of clients, so we can schedule the sync interval accordingly.
+      try {
+        int otherClientsCount = globalSession.getClientsDelegate().getClientsCount();
+        Logger.debug(LOG_TAG, "" + otherClientsCount + " other client(s).");
+        this.schedulePolicy.onSuccessfulSync(otherClientsCount);
+      } finally {
+        // Continue with the usual success flow.
+        syncDelegate.handleSuccess();
+      }
+    }
+
+    @Override
+    public void handleError(GlobalSession globalSession, Exception e) {
+      Logger.warn(LOG_TAG, "Global session failed."); // Exception will be dumped by delegate below.
+      syncDelegate.handleError(e);
+      // TODO: should we reduce the periodic sync interval?
+    }
+
+    @Override
+    public void handleAborted(GlobalSession globalSession, String reason) {
+      Logger.warn(LOG_TAG, "Global session aborted: " + reason);
+      syncDelegate.handleError(null);
+      // TODO: should we reduce the periodic sync interval?
+    }
+  };
+
+  /**
+   * Return true if the provided {@link BackoffHandler} isn't reporting that we're in
+   * a backoff state, or the provided {@link Bundle} contains flags that indicate
+   * we should force a sync.
+   */
+  private boolean shouldPerformSync(final BackoffHandler backoffHandler, final String kind, final Bundle extras) {
+    final long delay = backoffHandler.delayMilliseconds();
+    if (delay <= 0) {
+      return true;
+    }
+
+    if (extras == null) {
+      return false;
+    }
+
+    final boolean forced = extras.getBoolean(ContentResolver.SYNC_EXTRAS_IGNORE_BACKOFF, false);
+    if (forced) {
+      Logger.info(LOG_TAG, "Forced sync (" + kind + "): overruling remaining backoff of " + delay + "ms.");
+    } else {
+      Logger.info(LOG_TAG, "Not syncing (" + kind + "): must wait another " + delay + "ms.");
+    }
+    return forced;
+  }
+
+  protected void syncWithAssertion(final String audience,
+                                   final String assertion,
+                                   final URI tokenServerEndpointURI,
+                                   final BackoffHandler tokenBackoffHandler,
+                                   final SharedPreferences sharedPrefs,
+                                   final KeyBundle syncKeyBundle,
+                                   final String clientState,
+                                   final SessionCallback callback,
+                                   final Bundle extras,
+                                   final AndroidFxAccount fxAccount) {
+    final TokenServerClientDelegate delegate = new TokenServerClientDelegate() {
+      private boolean didReceiveBackoff = false;
+
+      @Override
+      public String getUserAgent() {
+        return FxAccountConstants.USER_AGENT;
+      }
+
+      @Override
+      public void handleSuccess(final TokenServerToken token) {
+        FxAccountUtils.pii(LOG_TAG, "Got token! uid is " + token.uid + " and endpoint is " + token.endpoint + ".");
+        fxAccount.releaseSharedAccountStateLock();
+
+        if (!didReceiveBackoff) {
+          // We must be OK to touch this token server.
+          tokenBackoffHandler.setEarliestNextRequest(0L);
+        }
+
+        final URI storageServerURI;
+        try {
+          storageServerURI = new URI(token.endpoint);
+        } catch (URISyntaxException e) {
+          handleError(e);
+          return;
+        }
+        final String storageHostname = storageServerURI.getHost();
+
+        // We back off on a per-host basis. When we have an endpoint URI from a token, we
+        // can check on the backoff status for that host.
+        // If we're supposed to be backing off, we abort the not-yet-started session.
+        final BackoffHandler storageBackoffHandler = new PrefsBackoffHandler(sharedPrefs, "sync.storage");
+        callback.setBackoffHandler(storageBackoffHandler);
+
+        String lastStorageHost = sharedPrefs.getString(PREF_BACKOFF_STORAGE_HOST, null);
+        final boolean storageHostIsUnchanged = lastStorageHost != null &&
+                                               lastStorageHost.equalsIgnoreCase(storageHostname);
+        if (storageHostIsUnchanged) {
+          Logger.debug(LOG_TAG, "Storage host is unchanged.");
+          if (!shouldPerformSync(storageBackoffHandler, "storage", extras)) {
+            Logger.info(LOG_TAG, "Not syncing: storage server requested backoff.");
+            callback.handleAborted(null, "Storage backoff");
+            return;
+          }
+        } else {
+          Logger.debug(LOG_TAG, "Received new storage host.");
+        }
+
+        // Invalidate the previous backoff, because our storage host has changed,
+        // or we never had one at all, or we're OK to sync.
+        storageBackoffHandler.setEarliestNextRequest(0L);
+
+        GlobalSession globalSession = null;
+        try {
+          final ClientsDataDelegate clientsDataDelegate = new SharedPreferencesClientsDataDelegate(sharedPrefs, getContext());
+          if (FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+            FxAccountUtils.pii(LOG_TAG, "Client device name is: '" + clientsDataDelegate.getClientName() + "'.");
+            FxAccountUtils.pii(LOG_TAG, "Client device data last modified: " + clientsDataDelegate.getLastModifiedTimestamp());
+          }
+
+          // We compute skew over time using SkewHandler. This yields an unchanging
+          // skew adjustment that the HawkAuthHeaderProvider uses to adjust its
+          // timestamps. Eventually we might want this to adapt within the scope of a
+          // global session.
+          final SkewHandler storageServerSkewHandler = SkewHandler.getSkewHandlerForHostname(storageHostname);
+          final long storageServerSkew = storageServerSkewHandler.getSkewInSeconds();
+          // We expect Sync to upload large sets of records. Calculating the
+          // payload verification hash for these record sets could be expensive,
+          // so we explicitly do not send payload verification hashes to the
+          // Sync storage endpoint.
+          final boolean includePayloadVerificationHash = false;
+          final AuthHeaderProvider authHeaderProvider = new HawkAuthHeaderProvider(token.id, token.key.getBytes("UTF-8"), includePayloadVerificationHash, storageServerSkew);
+
+          final Context context = getContext();
+          final SyncConfiguration syncConfig = new SyncConfiguration(token.uid, authHeaderProvider, sharedPrefs, syncKeyBundle);
+
+          Collection<String> knownStageNames = SyncConfiguration.validEngineNames();
+          syncConfig.stagesToSync = Utils.getStagesToSyncFromBundle(knownStageNames, extras);
+          syncConfig.setClusterURL(storageServerURI);
+
+          globalSession = new GlobalSession(syncConfig, callback, context, clientsDataDelegate);
+          globalSession.start();
+        } catch (Exception e) {
+          callback.handleError(globalSession, e);
+          return;
+        }
+      }
+
+      @Override
+      public void handleFailure(TokenServerException e) {
+        Logger.error(LOG_TAG, "Failed to get token.", e);
+        try {
+          // We should only get here *after* we're locked into the married state.
+          State state = fxAccount.getState();
+          if (state.getStateLabel() == StateLabel.Married) {
+            Married married = (Married) state;
+            fxAccount.setState(married.makeCohabitingState());
+          }
+        } finally {
+          fxAccount.releaseSharedAccountStateLock();
+        }
+        callback.handleError(null, e);
+      }
+
+      @Override
+      public void handleError(Exception e) {
+        Logger.error(LOG_TAG, "Failed to get token.", e);
+        fxAccount.releaseSharedAccountStateLock();
+        callback.handleError(null, e);
+      }
+
+      @Override
+      public void handleBackoff(int backoffSeconds) {
+        // This is the token server telling us to back off.
+        Logger.info(LOG_TAG, "Token server requesting backoff of " + backoffSeconds + "s. Backoff handler: " + tokenBackoffHandler);
+        didReceiveBackoff = true;
+
+        // If we've already stored a backoff, overrule it: we only use the server
+        // value for token server scheduling.
+        tokenBackoffHandler.setEarliestNextRequest(delay(backoffSeconds * 1000));
+      }
+
+      private long delay(long delay) {
+        return System.currentTimeMillis() + delay;
+      }
+    };
+
+    TokenServerClient tokenServerclient = new TokenServerClient(tokenServerEndpointURI, executor);
+    tokenServerclient.getTokenFromBrowserIDAssertion(assertion, true, clientState, delegate);
+  }
+
+  /**
+   * A trivial Sync implementation that does not cache client keys,
+   * certificates, or tokens.
+   *
+   * This should be replaced with a full {@link FxAccountAuthenticator}-based
+   * token implementation.
+   */
+  @Override
+  public void onPerformSync(final Account account, final Bundle extras, final String authority, ContentProviderClient provider, final SyncResult syncResult) {
+    Logger.setThreadLogTag(FxAccountConstants.GLOBAL_LOG_TAG);
+    Logger.resetLogging();
+
+    final Context context = getContext();
+    final AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+
+    Logger.info(LOG_TAG, "Syncing FxAccount" +
+        " account named like " + Utils.obfuscateEmail(account.name) +
+        " for authority " + authority +
+        " with instance " + this + ".");
+
+    Logger.info(LOG_TAG, "Account last synced at: " + fxAccount.getLastSyncedTimestamp());
+
+    if (FxAccountUtils.LOG_PERSONAL_INFORMATION) {
+      fxAccount.dump();
+    }
+
+    FirefoxAccounts.logSyncOptions(extras);
+
+    if (this.lastSyncRealtimeMillis > 0L &&
+        (this.lastSyncRealtimeMillis + MINIMUM_SYNC_DELAY_MILLIS) > SystemClock.elapsedRealtime() &&
+            !extras.getBoolean(ContentResolver.SYNC_EXTRAS_IGNORE_BACKOFF, false)) {
+      Logger.info(LOG_TAG, "Not syncing FxAccount " + Utils.obfuscateEmail(account.name) +
+                           ": minimum interval not met.");
+      TelemetryWrapper.addToHistogram(TelemetryContract.SYNC_FAILED_BACKOFF, 1);
+      return;
+    }
+
+    // Pickle in a background thread to avoid strict mode warnings.
+    ThreadPool.run(new Runnable() {
+      @Override
+      public void run() {
+        try {
+          AccountPickler.pickle(fxAccount, FxAccountConstants.ACCOUNT_PICKLE_FILENAME);
+        } catch (Exception e) {
+          // Should never happen, but we really don't want to die in a background thread.
+          Logger.warn(LOG_TAG, "Got exception pickling current account details; ignoring.", e);
+        }
+      }
+    });
+
+    final BlockingQueue<Result> latch = new LinkedBlockingQueue<>(1);
+
+    Collection<String> knownStageNames = SyncConfiguration.validEngineNames();
+    Collection<String> stageNamesToSync = Utils.getStagesToSyncFromBundle(knownStageNames, extras);
+
+    final SyncDelegate syncDelegate = new SyncDelegate(latch, syncResult, fxAccount, stageNamesToSync);
+
+    try {
+      // This will be the same chunk of SharedPreferences that we pass through to GlobalSession/SyncConfiguration.
+      final SharedPreferences sharedPrefs = fxAccount.getSyncPrefs();
+
+      final BackoffHandler backgroundBackoffHandler = new PrefsBackoffHandler(sharedPrefs, "background");
+      final BackoffHandler rateLimitBackoffHandler = new PrefsBackoffHandler(sharedPrefs, "rate");
+
+      // If this sync was triggered by user action, this will be true.
+      final boolean isImmediate = (extras != null) &&
+                                  (extras.getBoolean(ContentResolver.SYNC_EXTRAS_UPLOAD, false) ||
+                                   extras.getBoolean(ContentResolver.SYNC_EXTRAS_IGNORE_BACKOFF, false));
+
+      // If it's not an immediate sync, it must be either periodic or tickled.
+      // Check our background rate limiter.
+      if (!isImmediate) {
+        if (!shouldPerformSync(backgroundBackoffHandler, "background", extras)) {
+          syncDelegate.rejectSync();
+          return;
+        }
+      }
+
+      // Regardless, let's make sure we're not syncing too often.
+      if (!shouldPerformSync(rateLimitBackoffHandler, "rate", extras)) {
+        syncDelegate.postponeSync(rateLimitBackoffHandler.delayMilliseconds());
+        return;
+      }
+
+      final SchedulePolicy schedulePolicy = new FxAccountSchedulePolicy(context, fxAccount);
+
+      // Set a small scheduled 'backoff' to rate-limit the next sync,
+      // and extend the background delay even further into the future.
+      schedulePolicy.configureBackoffMillisBeforeSyncing(rateLimitBackoffHandler, backgroundBackoffHandler);
+
+      final String tokenServerEndpoint = fxAccount.getTokenServerURI();
+      final URI tokenServerEndpointURI = new URI(tokenServerEndpoint);
+      final String audience = FxAccountUtils.getAudienceForURL(tokenServerEndpoint);
+
+      try {
+        // The clock starts... now!
+        fxAccount.acquireSharedAccountStateLock(FxAccountSyncAdapter.LOG_TAG);
+      } catch (InterruptedException e) {
+        // OK, skip this sync.
+        syncDelegate.handleError(e);
+        return;
+      }
+
+      final State state;
+      try {
+        state = fxAccount.getState();
+      } catch (Exception e) {
+        fxAccount.releaseSharedAccountStateLock();
+        syncDelegate.handleError(e);
+        return;
+      }
+
+      TelemetryWrapper.addToHistogram(TelemetryContract.SYNC_STARTED, 1);
+
+      final FxAccountLoginStateMachine stateMachine = new FxAccountLoginStateMachine();
+      stateMachine.advance(state, StateLabel.Married, new FxADefaultLoginStateMachineDelegate(context, fxAccount) {
+        @Override
+        public void handleNotMarried(State notMarried) {
+          Logger.info(LOG_TAG, "handleNotMarried: in " + notMarried.getStateLabel());
+          schedulePolicy.onHandleFinal(notMarried.getNeededAction());
+          syncDelegate.handleCannotSync(notMarried);
+        }
+
+        private boolean shouldRequestToken(final BackoffHandler tokenBackoffHandler, final Bundle extras) {
+          return shouldPerformSync(tokenBackoffHandler, "token", extras);
+        }
+
+        @Override
+        public void handleMarried(Married married) {
+          schedulePolicy.onHandleFinal(married.getNeededAction());
+          Logger.info(LOG_TAG, "handleMarried: in " + married.getStateLabel());
+
+          try {
+            final String assertion = married.generateAssertion(audience, JSONWebTokenUtils.DEFAULT_ASSERTION_ISSUER);
+
+            /*
+             * At this point we're in the correct state to sync, and we're ready to fetch
+             * a token and do some work.
+             *
+             * But first we need to do two things:
+             * 1. Check to see whether we're in a backoff situation for the token server.
+             *    If we are, but we're not forcing a sync, then we go no further.
+             * 2. Clear an existing backoff (if we're syncing it doesn't matter, and if
+             *    we're forcing we'll get a new backoff if things are still bad).
+             *
+             * Note that we don't check the storage backoff before the token dance: the token
+             * server tells us which server we're syncing to!
+             *
+             * That logic lives in the TokenServerClientDelegate elsewhere in this file.
+             */
+
+            // Strictly speaking this backoff check could be done prior to walking through
+            // the login state machine, allowing us to short-circuit sooner.
+            // We don't expect many token server backoffs, and most users will be sitting
+            // in the Married state, so instead we simply do this here, once.
+            final BackoffHandler tokenBackoffHandler = new PrefsBackoffHandler(sharedPrefs, "token");
+            if (!shouldRequestToken(tokenBackoffHandler, extras)) {
+              Logger.info(LOG_TAG, "Not syncing (token server).");
+              syncDelegate.postponeSync(tokenBackoffHandler.delayMilliseconds());
+              return;
+            }
+
+            final SessionCallback sessionCallback = new SessionCallback(syncDelegate, schedulePolicy);
+            final KeyBundle syncKeyBundle = married.getSyncKeyBundle();
+            final String clientState = married.getClientState();
+            syncWithAssertion(audience, assertion, tokenServerEndpointURI, tokenBackoffHandler, sharedPrefs, syncKeyBundle, clientState, sessionCallback, extras, fxAccount);
+
+            // Register the device if necessary (asynchronous, in another thread)
+            if (fxAccount.getDeviceRegistrationVersion() != FxAccountDeviceRegistrator.DEVICE_REGISTRATION_VERSION
+                || TextUtils.isEmpty(fxAccount.getDeviceId())) {
+              FxAccountDeviceRegistrator.register(context);
+            }
+
+            // Force fetch the profile avatar information. (asynchronous, in another thread)
+            Logger.info(LOG_TAG, "Fetching profile avatar information.");
+            fxAccount.fetchProfileJSON();
+          } catch (Exception e) {
+            syncDelegate.handleError(e);
+            return;
+          }
+        }
+      });
+
+      latch.take();
+    } catch (Exception e) {
+      Logger.error(LOG_TAG, "Got error syncing.", e);
+      syncDelegate.handleError(e);
+    } finally {
+      fxAccount.releaseSharedAccountStateLock();
+    }
+
+    Logger.info(LOG_TAG, "Syncing done.");
+    lastSyncRealtimeMillis = SystemClock.elapsedRealtime();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncDelegate.java
new file mode 100644
index 000000000..71148f66c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncDelegate.java
@@ -0,0 +1,110 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.sync;
+
+import java.util.concurrent.BlockingQueue;
+
+import org.mozilla.gecko.fxa.login.State;
+
+import android.content.SyncResult;
+
+public class FxAccountSyncDelegate {
+  public enum Result {
+    Success,
+    Error,
+    Postponed,
+    Rejected,
+  }
+
+  protected final BlockingQueue<Result> latch;
+  protected final SyncResult syncResult;
+
+  public FxAccountSyncDelegate(BlockingQueue<Result> latch, SyncResult syncResult) {
+    if (latch == null) {
+      throw new IllegalArgumentException("latch must not be null");
+    }
+    if (syncResult == null) {
+      throw new IllegalArgumentException("syncResult must not be null");
+    }
+    this.latch = latch;
+    this.syncResult = syncResult;
+  }
+
+  /**
+   * No error!  Say that we made progress.
+   */
+  protected void setSyncResultSuccess() {
+    syncResult.stats.numUpdates += 1;
+  }
+
+  /**
+   * Soft error. Say that we made progress, so that Android will sync us again
+   * after exponential backoff.
+   */
+  protected void setSyncResultSoftError() {
+    syncResult.stats.numUpdates += 1;
+    syncResult.stats.numIoExceptions += 1;
+  }
+
+  /**
+   * Hard error. We don't want Android to sync us again, even if we make
+   * progress, until the user intervenes.
+   */
+  protected void setSyncResultHardError() {
+    syncResult.stats.numAuthExceptions += 1;
+  }
+
+  public void handleSuccess() {
+    setSyncResultSuccess();
+    latch.offer(Result.Success);
+  }
+
+  public void handleError(Exception e) {
+    setSyncResultSoftError();
+    latch.offer(Result.Error);
+  }
+
+  /**
+   * When the login machine terminates, we might not be in the
+   * <code>Married</code> state, and therefore we can't sync. This method
+   * messages as much to the user.
+   * <p>
+   * To avoid stopping us syncing altogether, we set a soft error rather than
+   * a hard error. In future, we would like to set a hard error if we are in,
+   * for example, the <code>Separated</code> state, and then have some user
+   * initiated activity mark the Android account as ready to sync again. This
+   * is tricky, though, so we play it safe for now.
+   *
+   * @param finalState
+   *          that login machine ended in.
+   */
+  public void handleCannotSync(State finalState) {
+    setSyncResultSoftError();
+    latch.offer(Result.Error);
+  }
+
+  public void postponeSync(long millis) {
+    if (millis > 0) {
+      // delayUntil is broken: https://code.google.com/p/android/issues/detail?id=65669
+      // So we don't bother doing this. Instead, we rely on the periodic sync
+      // we schedule, and the backoff handler for the rest.
+      /*
+      Logger.warn(LOG_TAG, "Postponing sync by " + millis + "ms.");
+      syncResult.delayUntil = millis / 1000;
+       */
+    }
+    setSyncResultSoftError();
+    latch.offer(Result.Postponed);
+  }
+
+  /**
+   * Simply don't sync, without setting any error flags.
+   * This is the appropriate behavior when a routine backoff has not yet
+   * been met.
+   */
+  public void rejectSync() {
+    latch.offer(Result.Rejected);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncService.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncService.java
new file mode 100644
index 000000000..59c06ca97
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncService.java
@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.sync;
+
+import android.app.Service;
+import android.content.Intent;
+import android.os.IBinder;
+
+public class FxAccountSyncService extends Service {
+  private static final Object syncAdapterLock = new Object();
+  private static FxAccountSyncAdapter syncAdapter;
+
+  @Override
+  public void onCreate() {
+    synchronized (syncAdapterLock) {
+      if (syncAdapter == null) {
+        syncAdapter = new FxAccountSyncAdapter(getApplicationContext(), true);
+      }
+    }
+  }
+
+  @Override
+  public IBinder onBind(Intent intent) {
+    return syncAdapter.getSyncAdapterBinder();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncStatusHelper.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncStatusHelper.java
new file mode 100644
index 000000000..ca64d4f87
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/FxAccountSyncStatusHelper.java
@@ -0,0 +1,113 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.sync;
+
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.WeakHashMap;
+
+import org.mozilla.gecko.fxa.SyncStatusListener;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.util.ThreadUtils;
+
+import android.content.ContentResolver;
+import android.content.SyncStatusObserver;
+
+/**
+ * Abstract away some details of Android's SyncStatusObserver.
+ * <p>
+ * Provides a simplified sync started/sync finished delegate.
+ */
+public class FxAccountSyncStatusHelper implements SyncStatusObserver {
+  @SuppressWarnings("unused")
+  private static final String LOG_TAG = FxAccountSyncStatusHelper.class.getSimpleName();
+
+  protected static FxAccountSyncStatusHelper sInstance;
+
+  public synchronized static FxAccountSyncStatusHelper getInstance() {
+    if (sInstance == null) {
+      sInstance = new FxAccountSyncStatusHelper();
+    }
+    return sInstance;
+  }
+
+  // Used to unregister this as a listener.
+  protected Object handle;
+
+  // Maps delegates to whether their underlying Android account was syncing the
+  // last time we observed a status change.
+  protected Map<SyncStatusListener, Boolean> delegates = new WeakHashMap<SyncStatusListener, Boolean>();
+
+  @Override
+  public synchronized void onStatusChanged(int which) {
+    for (Entry<SyncStatusListener, Boolean> entry : delegates.entrySet()) {
+      final SyncStatusListener delegate = entry.getKey();
+      final AndroidFxAccount fxAccount = new AndroidFxAccount(delegate.getContext(), delegate.getAccount());
+      final boolean active = fxAccount.isCurrentlySyncing();
+      // Remember for later.
+      boolean wasActiveLastTime = entry.getValue();
+      // It's okay to update the value of an entry while iterating the entrySet.
+      entry.setValue(active);
+
+      if (active && !wasActiveLastTime) {
+        // We've started a sync.
+        ThreadUtils.postToUiThread(new Runnable() {
+          @Override
+          public void run() {
+            delegate.onSyncStarted();
+          }
+        });
+      }
+
+      if (!active && wasActiveLastTime) {
+        // We've finished a sync.
+        ThreadUtils.postToUiThread(new Runnable() {
+          @Override
+          public void run() {
+            delegate.onSyncFinished();
+          }
+        });
+      }
+    }
+  }
+
+  protected void addListener() {
+    final int mask = ContentResolver.SYNC_OBSERVER_TYPE_ACTIVE;
+    if (this.handle != null) {
+      throw new IllegalStateException("Already registered this as an observer?");
+    }
+    this.handle = ContentResolver.addStatusChangeListener(mask, this);
+  }
+
+  protected void removeListener() {
+    Object handle = this.handle;
+    this.handle = null;
+    if (handle != null) {
+      ContentResolver.removeStatusChangeListener(handle);
+    }
+  }
+
+  public synchronized void startObserving(SyncStatusListener delegate) {
+    if (delegate == null) {
+      throw new IllegalArgumentException("delegate must not be null");
+    }
+    if (delegates.containsKey(delegate)) {
+      return;
+    }
+    // If we are the first delegate to the party, start listening.
+    if (delegates.isEmpty()) {
+      addListener();
+    }
+    delegates.put(delegate, Boolean.FALSE);
+  }
+
+  public synchronized void stopObserving(SyncStatusListener delegate) {
+    delegates.remove(delegate);
+    // If we are the last delegate leaving the party, stop listening.
+    if (delegates.isEmpty()) {
+      removeListener();
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/SchedulePolicy.java b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/SchedulePolicy.java
new file mode 100644
index 000000000..809191f5e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/fxa/sync/SchedulePolicy.java
@@ -0,0 +1,43 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.fxa.sync;
+
+import org.mozilla.gecko.fxa.login.State.Action;
+import org.mozilla.gecko.sync.BackoffHandler;
+
+public interface SchedulePolicy {
+  /**
+   * Call this with the number of other clients syncing to the account.
+   */
+  public abstract void onSuccessfulSync(int otherClientsCount);
+  public abstract void onHandleFinal(Action needed);
+  public abstract void onUpgradeRequired();
+  public abstract void onUnauthorized();
+
+  /**
+   * Before a sync we typically wish to adjust our backoff policy. This cleans
+   * the slate prior to encountering a new backoff, and also functions as a rate
+   * limiter.
+   *
+   * The {@link SchedulePolicy} acts as a controller for the {@link BackoffHandler}.
+   * As a result of calling these two methods, the {@link BackoffHandler} will be
+   * mutated, and additional side-effects (such as scheduling periodic syncs) can
+   * occur.
+   *
+   * @param rateHandler the backoff handler to configure for basic rate limiting.
+   * @param backgroundHandler the backoff handler to configure for background operations.
+   */
+  public abstract void configureBackoffMillisBeforeSyncing(BackoffHandler rateHandler, BackoffHandler backgroundHandler);
+
+  /**
+   * We received an explicit backoff instruction, typically from a server.
+   *
+   * @param onlyExtend
+   *          if <code>true</code>, the backoff handler will be asked to update
+   *          its backoff only if the provided value is greater than the current
+   *          backoff.
+   */
+  public abstract void configureBackoffMillisOnBackoff(BackoffHandler backoffHandler, long backoffMillis, boolean onlyExtend);
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/push/RegisterUserAgentResponse.java b/mobile/android/services/src/main/java/org/mozilla/gecko/push/RegisterUserAgentResponse.java
new file mode 100644
index 000000000..3bbb7e8b4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/push/RegisterUserAgentResponse.java
@@ -0,0 +1,19 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.push;
+
+/**
+ * Thin container for a register User-Agent response.
+ */
+public class RegisterUserAgentResponse {
+    public final String uaid;
+    public final String secret;
+
+    public RegisterUserAgentResponse(String uaid, String secret) {
+        this.uaid = uaid;
+        this.secret = secret;
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/push/SubscribeChannelResponse.java b/mobile/android/services/src/main/java/org/mozilla/gecko/push/SubscribeChannelResponse.java
new file mode 100644
index 000000000..009a7f838
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/push/SubscribeChannelResponse.java
@@ -0,0 +1,19 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.push;
+
+/**
+ * Thin container for a subscribe channel response.
+ */
+public class SubscribeChannelResponse {
+    public final String channelID;
+    public final String endpoint;
+
+    public SubscribeChannelResponse(String channelID, String endpoint) {
+        this.channelID = channelID;
+        this.endpoint = endpoint;
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/push/autopush/AutopushClient.java b/mobile/android/services/src/main/java/org/mozilla/gecko/push/autopush/AutopushClient.java
new file mode 100644
index 000000000..8edd92f9e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/push/autopush/AutopushClient.java
@@ -0,0 +1,410 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.push.autopush;
+
+import android.text.TextUtils;
+
+import org.mozilla.gecko.Locales;
+import org.mozilla.gecko.fxa.FxAccountConstants;
+import org.mozilla.gecko.push.RegisterUserAgentResponse;
+import org.mozilla.gecko.push.SubscribeChannelResponse;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.BaseResource;
+import org.mozilla.gecko.sync.net.BaseResourceDelegate;
+import org.mozilla.gecko.sync.net.BearerAuthHeaderProvider;
+import org.mozilla.gecko.sync.net.Resource;
+import org.mozilla.gecko.sync.net.SyncResponse;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.security.GeneralSecurityException;
+import java.util.Locale;
+import java.util.concurrent.Executor;
+
+import ch.boye.httpclientandroidlib.HttpEntity;
+import ch.boye.httpclientandroidlib.HttpHeaders;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.ClientProtocolException;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+
+
+/**
+ * Interact with the autopush endpoint HTTP API.
+ * <p/>
+ * The API is a Mozilla-proprietary interface, and not even specified to Mozilla's usual ad-hoc standards.
+ * This client is written against a work-in-progress, un-deployed upstream commit.
+ */
+public class AutopushClient {
+    protected static final String LOG_TAG = AutopushClient.class.getSimpleName();
+
+    protected static final String ACCEPT_HEADER = "application/json;charset=utf-8";
+    protected static final String TYPE = "gcm";
+
+    protected static final String JSON_KEY_UAID = "uaid";
+    protected static final String JSON_KEY_SECRET = "secret";
+    protected static final String JSON_KEY_CHANNEL_ID = "channelID";
+    protected static final String JSON_KEY_ENDPOINT = "endpoint";
+
+    protected static final String[] REGISTER_USER_AGENT_RESPONSE_REQUIRED_STRING_FIELDS = new String[] { JSON_KEY_UAID, JSON_KEY_SECRET, JSON_KEY_CHANNEL_ID, JSON_KEY_ENDPOINT };
+    protected static final String[] REGISTER_CHANNEL_RESPONSE_REQUIRED_STRING_FIELDS = new String[] { JSON_KEY_CHANNEL_ID, JSON_KEY_ENDPOINT };
+
+    public static final String JSON_KEY_CODE = "code";
+    public static final String JSON_KEY_ERRNO = "errno";
+    public static final String JSON_KEY_ERROR = "error";
+    public static final String JSON_KEY_MESSAGE = "message";
+
+    protected static final String[] requiredErrorStringFields = { JSON_KEY_ERROR, JSON_KEY_MESSAGE };
+    protected static final String[] requiredErrorLongFields = { JSON_KEY_CODE, JSON_KEY_ERRNO };
+
+    /**
+     * The server's URI.
+     * <p>
+     * We assume throughout that this ends with a trailing slash (and guarantee as
+     * much in the constructor).
+     */
+    public final String serverURI;
+
+    protected final Executor executor;
+
+    public AutopushClient(String serverURI, Executor executor) {
+        if (serverURI == null) {
+            throw new IllegalArgumentException("Must provide a server URI.");
+        }
+        if (executor == null) {
+            throw new IllegalArgumentException("Must provide a non-null executor.");
+        }
+        this.serverURI = serverURI.endsWith("/") ? serverURI : serverURI + "/";
+        if (!this.serverURI.endsWith("/")) {
+            throw new IllegalArgumentException("Constructed serverURI must end with a trailing slash: " + this.serverURI);
+        }
+        this.executor = executor;
+    }
+
+    /**
+     * A legal autopush server URL includes a sender ID embedded into it.  Extract it.
+     *
+     * @return a non-null non-empty sender ID.
+     * @throws AutopushClientException on failure.
+     */
+    public String getSenderIDFromServerURI() throws AutopushClientException {
+        // Turn "https://updates-autopush-dev.stage.mozaws.net/v1/gcm/829133274407/" into "829133274407".
+        final String[] parts = serverURI.split("/", -1); // The -1 keeps the trailing empty part.
+        if (parts.length < 3) {
+            throw new AutopushClientException("Could not get sender ID from autopush server URI: " + serverURI);
+        }
+        if (!TextUtils.isEmpty(parts[parts.length - 1])) {
+            // We guarantee a trailing slash, so we should always have an empty part at the tail.
+            throw new AutopushClientException("Could not get sender ID from autopush server URI: " + serverURI);
+        }
+        if (!TextUtils.equals("gcm", parts[parts.length - 3])) {
+            // We should always have /gcm/senderID/.
+            throw new AutopushClientException("Could not get sender ID from autopush server URI: " + serverURI);
+        }
+        final String senderID = parts[parts.length - 2];
+        if (TextUtils.isEmpty(senderID)) {
+            // Something is horribly wrong -- we have /gcm//.  Abort.
+            throw new AutopushClientException("Could not get sender ID from autopush server URI: " + serverURI);
+        }
+        return senderID;
+    }
+
+    /**
+     * Process a typed value extracted from a successful response (in an
+     * endpoint-dependent way).
+     */
+    public interface RequestDelegate<T> {
+        void handleError(Exception e);
+        void handleFailure(AutopushClientException e);
+        void handleSuccess(T result);
+    }
+
+    /**
+     * Intepret a response from the autopush server.
+     * <p>
+     * Throw an appropriate exception on errors; otherwise, return the response's
+     * status code.
+     *
+     * @return response's HTTP status code.
+     * @throws AutopushClientException
+     */
+    public static int validateResponse(HttpResponse response) throws AutopushClientException {
+        final int status = response.getStatusLine().getStatusCode();
+        if (200 <= status && status <= 299) {
+            return status;
+        }
+        long code;
+        long errno;
+        String error;
+        String message;
+        String info;
+        ExtendedJSONObject body;
+        try {
+            body = new SyncStorageResponse(response).jsonObjectBody();
+            // TODO: The service doesn't do the right thing yet :(
+            // body.throwIfFieldsMissingOrMisTyped(requiredErrorStringFields, String.class);
+            body.throwIfFieldsMissingOrMisTyped(requiredErrorLongFields, Long.class);
+            // Would throw above if missing; the -1 defaults quiet NPE warnings.
+            code = body.getLong(JSON_KEY_CODE, -1);
+            errno = body.getLong(JSON_KEY_ERRNO, -1);
+            error = body.getString(JSON_KEY_ERROR);
+            message = body.getString(JSON_KEY_MESSAGE);
+        } catch (Exception e) {
+            throw new AutopushClientException.AutopushClientMalformedResponseException(response);
+        }
+        throw new AutopushClientException.AutopushClientRemoteException(response, code, errno, error, message, body);
+    }
+
+    protected <T> void invokeHandleError(final RequestDelegate<T> delegate, final Exception e) {
+        executor.execute(new Runnable() {
+            @Override
+            public void run() {
+                delegate.handleError(e);
+            }
+        });
+    }
+
+    protected <T> void post(BaseResource resource, final ExtendedJSONObject requestBody, final RequestDelegate<T> delegate) {
+        try {
+            if (requestBody == null) {
+                resource.post((HttpEntity) null);
+            } else {
+                resource.post(requestBody);
+            }
+        } catch (Exception e) {
+            invokeHandleError(delegate, e);
+            return;
+        }
+    }
+
+    /**
+     * Translate resource callbacks into request callbacks invoked on the provided
+     * executor.
+     * <p>
+     * Override <code>handleSuccess</code> to parse the body of the resource
+     * request and call the request callback. <code>handleSuccess</code> is
+     * invoked via the executor, so you don't need to delegate further.
+     */
+    protected abstract class ResourceDelegate<T> extends BaseResourceDelegate {
+        protected abstract void handleSuccess(final int status, HttpResponse response, final ExtendedJSONObject body);
+
+        protected final String secret;
+        protected final RequestDelegate<T> delegate;
+
+        /**
+         * Create a delegate for an un-authenticated resource.
+         */
+        public ResourceDelegate(final Resource resource, final String secret, final RequestDelegate<T> delegate) {
+            super(resource);
+            this.delegate = delegate;
+            this.secret = secret;
+        }
+
+        @Override
+        public AuthHeaderProvider getAuthHeaderProvider() {
+            if (secret != null) {
+                return new BearerAuthHeaderProvider(secret);
+            }
+            return null;
+        }
+
+        @Override
+        public String getUserAgent() {
+            return FxAccountConstants.USER_AGENT;
+        }
+
+        @Override
+        public void handleHttpResponse(HttpResponse response) {
+            try {
+                final int status = validateResponse(response);
+                invokeHandleSuccess(status, response);
+            } catch (AutopushClientException e) {
+                invokeHandleFailure(e);
+            }
+        }
+
+        protected void invokeHandleFailure(final AutopushClientException e) {
+            executor.execute(new Runnable() {
+                @Override
+                public void run() {
+                    delegate.handleFailure(e);
+                }
+            });
+        }
+
+        protected void invokeHandleSuccess(final int status, final HttpResponse response) {
+            executor.execute(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        ExtendedJSONObject body = new SyncResponse(response).jsonObjectBody();
+                        ResourceDelegate.this.handleSuccess(status, response, body);
+                    } catch (Exception e) {
+                        delegate.handleError(e);
+                    }
+                }
+            });
+        }
+
+        @Override
+        public void handleHttpProtocolException(final ClientProtocolException e) {
+            invokeHandleError(delegate, e);
+        }
+
+        @Override
+        public void handleHttpIOException(IOException e) {
+            invokeHandleError(delegate, e);
+        }
+
+        @Override
+        public void handleTransportException(GeneralSecurityException e) {
+            invokeHandleError(delegate, e);
+        }
+
+        @Override
+        public void addHeaders(HttpRequestBase request, DefaultHttpClient client) {
+            super.addHeaders(request, client);
+
+            // The basics.
+            final Locale locale = Locale.getDefault();
+            request.addHeader(HttpHeaders.ACCEPT_LANGUAGE, Locales.getLanguageTag(locale));
+            request.addHeader(HttpHeaders.ACCEPT, ACCEPT_HEADER);
+        }
+    }
+
+    public void registerUserAgent(final String token, RequestDelegate<RegisterUserAgentResponse> delegate) {
+        BaseResource resource;
+        try {
+            resource = new BaseResource(new URI(serverURI + "registration"));
+        } catch (URISyntaxException e) {
+            invokeHandleError(delegate, e);
+            return;
+        }
+
+        resource.delegate = new ResourceDelegate<RegisterUserAgentResponse>(resource, null, delegate) {
+            @Override
+            public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+                try {
+                    body.throwIfFieldsMissingOrMisTyped(REGISTER_USER_AGENT_RESPONSE_REQUIRED_STRING_FIELDS, String.class);
+                    final String uaid = body.getString(JSON_KEY_UAID);
+                    final String secret = body.getString(JSON_KEY_SECRET);
+                    delegate.handleSuccess(new RegisterUserAgentResponse(uaid, secret));
+                    return;
+                } catch (Exception e) {
+                    delegate.handleError(e);
+                    return;
+                }
+            }
+        };
+
+        final ExtendedJSONObject body = new ExtendedJSONObject();
+        body.put("type", TYPE);
+        body.put("token", token);
+
+        resource.post(body);
+    }
+
+    public void reregisterUserAgent(final String uaid, final String secret, final String token, RequestDelegate<Void> delegate) {
+        final BaseResource resource;
+        try {
+            resource = new BaseResource(new URI(serverURI + "registration/" + uaid));
+        } catch (Exception e) {
+            invokeHandleError(delegate, e);
+            return;
+        }
+
+        resource.delegate = new ResourceDelegate<Void>(resource, secret, delegate) {
+            @Override
+            public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+                try {
+                    delegate.handleSuccess(null);
+                    return;
+                } catch (Exception e) {
+                    delegate.handleError(e);
+                    return;
+                }
+            }
+        };
+
+        final ExtendedJSONObject body = new ExtendedJSONObject();
+        body.put("type", TYPE);
+        body.put("token", token);
+
+        resource.put(body);
+    }
+
+
+    public void subscribeChannel(final String uaid, final String secret, final String appServerKey, RequestDelegate<SubscribeChannelResponse> delegate) {
+        final BaseResource resource;
+        try {
+            resource = new BaseResource(new URI(serverURI + "registration/" + uaid + "/subscription"));
+        } catch (Exception e) {
+            invokeHandleError(delegate, e);
+            return;
+        }
+
+        resource.delegate = new ResourceDelegate<SubscribeChannelResponse>(resource, secret, delegate) {
+            @Override
+            public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+                try {
+                    body.throwIfFieldsMissingOrMisTyped(REGISTER_CHANNEL_RESPONSE_REQUIRED_STRING_FIELDS, String.class);
+                    final String channelID = body.getString(JSON_KEY_CHANNEL_ID);
+                    final String endpoint = body.getString(JSON_KEY_ENDPOINT);
+                    delegate.handleSuccess(new SubscribeChannelResponse(channelID, endpoint));
+                    return;
+                } catch (Exception e) {
+                    delegate.handleError(e);
+                    return;
+                }
+            }
+        };
+
+        final ExtendedJSONObject body = new ExtendedJSONObject();
+        body.put("key", appServerKey);
+        resource.post(body);
+    }
+
+    public void unsubscribeChannel(final String uaid, final String secret, final String channelID, RequestDelegate<Void> delegate) {
+        final BaseResource resource;
+        try {
+            resource = new BaseResource(new URI(serverURI + "registration/" + uaid + "/subscription/" + channelID));
+        } catch (Exception e) {
+            invokeHandleError(delegate, e);
+            return;
+        }
+
+        resource.delegate = new ResourceDelegate<Void>(resource, secret, delegate) {
+            @Override
+            public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+                delegate.handleSuccess(null);
+            }
+        };
+
+        resource.delete();
+    }
+
+    public void unregisterUserAgent(final String uaid, final String secret, RequestDelegate<Void> delegate) {
+        final BaseResource resource;
+        try {
+            resource = new BaseResource(new URI(serverURI + "registration/" + uaid));
+        } catch (Exception e) {
+            invokeHandleError(delegate, e);
+            return;
+        }
+
+        resource.delegate = new ResourceDelegate<Void>(resource, secret, delegate) {
+            @Override
+            public void handleSuccess(int status, HttpResponse response, ExtendedJSONObject body) {
+                delegate.handleSuccess(null);
+            }
+        };
+
+        resource.delete();
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/push/autopush/AutopushClientException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/push/autopush/AutopushClientException.java
new file mode 100644
index 000000000..e3fda7a45
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/push/autopush/AutopushClientException.java
@@ -0,0 +1,81 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.push.autopush;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.HttpStatus;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.HTTPFailureException;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+public class AutopushClientException extends Exception {
+    private static final long serialVersionUID = 7953459541558266500L;
+
+    public AutopushClientException(String detailMessage) {
+        super(detailMessage);
+    }
+
+    public AutopushClientException(Exception e) {
+        super(e);
+    }
+
+    public boolean isTransientError() {
+        return false;
+    }
+
+    public static class AutopushClientRemoteException extends AutopushClientException {
+        private static final long serialVersionUID = 2209313149952001000L;
+
+        public final HttpResponse response;
+        public final long httpStatusCode;
+        public final long apiErrorNumber;
+        public final String error;
+        public final String message;
+        public final ExtendedJSONObject body;
+
+        public AutopushClientRemoteException(HttpResponse response, long httpStatusCode, long apiErrorNumber, String error, String message, ExtendedJSONObject body) {
+            super(new HTTPFailureException(new SyncStorageResponse(response)));
+            if (body == null) {
+                throw new IllegalArgumentException("body must not be null");
+            }
+            this.response = response;
+            this.httpStatusCode = httpStatusCode;
+            this.apiErrorNumber = apiErrorNumber;
+            this.error = error;
+            this.message = message;
+            this.body = body;
+        }
+
+        @Override
+        public String toString() {
+            return "<AutopushClientRemoteException " + this.httpStatusCode + " [" + this.apiErrorNumber + "]: " + this.message + ">";
+        }
+
+        public boolean isInvalidAuthentication() {
+            return httpStatusCode == HttpStatus.SC_UNAUTHORIZED;
+        }
+
+        public boolean isNotFound() {
+            return httpStatusCode == HttpStatus.SC_NOT_FOUND;
+        }
+
+        public boolean isGone() {
+            return httpStatusCode == HttpStatus.SC_GONE;
+        }
+
+        @Override
+        public boolean isTransientError() {
+            return httpStatusCode >= 500;
+        }
+    }
+
+    public static class AutopushClientMalformedResponseException extends AutopushClientRemoteException {
+        private static final long serialVersionUID = 2209313149952001909L;
+
+        public AutopushClientMalformedResponseException(HttpResponse response) {
+            super(response, 0, 999, "Response malformed", "Response malformed", new ExtendedJSONObject());
+        }
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/AlreadySyncingException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/AlreadySyncingException.java
new file mode 100644
index 000000000..75eb5ad37
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/AlreadySyncingException.java
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import org.mozilla.gecko.sync.stage.GlobalSyncStage.Stage;
+
+import android.content.SyncResult;
+
+public class AlreadySyncingException extends SyncException {
+  Stage inState;
+  public AlreadySyncingException(Stage currentState) {
+    inState = currentState;
+  }
+
+  private static final long serialVersionUID = -5647548462539009893L;
+
+  @Override
+  public void updateStats(GlobalSession globalSession, SyncResult syncResult) {
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/BackoffHandler.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/BackoffHandler.java
new file mode 100644
index 000000000..abb880621
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/BackoffHandler.java
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+
+public interface BackoffHandler {
+  public long getEarliestNextRequest();
+
+  /**
+   * Provide a timestamp in millis before which we shouldn't sync again.
+   * Overrides any existing value.
+   *
+   * @param next
+   *          a timestamp in milliseconds.
+   */
+  public void setEarliestNextRequest(long next);
+
+  /**
+   * Provide a timestamp in millis before which we shouldn't sync again. Only
+   * change our persisted value if it's later than the existing time.
+   *
+   * @param next
+   *          a timestamp in milliseconds.
+   */
+  public void extendEarliestNextRequest(long next);
+
+  /**
+   * Return the number of milliseconds until we're allowed to sync again,
+   * or 0 if now is fine.
+   */
+  public long delayMilliseconds();
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/BadRequiredFieldJSONException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/BadRequiredFieldJSONException.java
new file mode 100644
index 000000000..3db93652d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/BadRequiredFieldJSONException.java
@@ -0,0 +1,5 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CollectionKeys.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CollectionKeys.java
new file mode 100644
index 000000000..1fd363bcb
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CollectionKeys.java
@@ -0,0 +1,199 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.json.simple.JSONArray;
+import org.mozilla.apache.commons.codec.binary.Base64;
+import org.mozilla.gecko.sync.crypto.CryptoException;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+
+public class CollectionKeys {
+  private KeyBundle                  defaultKeyBundle     = null;
+  private final HashMap<String, KeyBundle> collectionKeyBundles = new HashMap<String, KeyBundle>();
+
+  /**
+   * Randomly generate a basic CollectionKeys object.
+   * @throws CryptoException
+   */
+  public static CollectionKeys generateCollectionKeys() throws CryptoException {
+    CollectionKeys ck = new CollectionKeys();
+    ck.clear();
+    ck.defaultKeyBundle = KeyBundle.withRandomKeys();
+    // TODO: eventually we would like to keep per-collection keys, just generate
+    // new ones as appropriate.
+    return ck;
+  }
+
+  public KeyBundle defaultKeyBundle() throws NoCollectionKeysSetException {
+    if (this.defaultKeyBundle == null) {
+      throw new NoCollectionKeysSetException();
+    }
+    return this.defaultKeyBundle;
+  }
+
+  public boolean keyBundleForCollectionIsNotDefault(String collection) {
+    return collectionKeyBundles.containsKey(collection);
+  }
+
+  public KeyBundle keyBundleForCollection(String collection)
+      throws NoCollectionKeysSetException {
+    if (this.defaultKeyBundle == null) {
+      throw new NoCollectionKeysSetException();
+    }
+    if (keyBundleForCollectionIsNotDefault(collection)) {
+      return collectionKeyBundles.get(collection);
+    }
+    return this.defaultKeyBundle;
+  }
+
+  /**
+   * Take a pair of values in a JSON array, handing them off to KeyBundle to
+   * produce a usable keypair.
+   */
+  private static KeyBundle arrayToKeyBundle(JSONArray array) throws UnsupportedEncodingException {
+    String encKeyStr  = (String) array.get(0);
+    String hmacKeyStr = (String) array.get(1);
+    return KeyBundle.fromBase64EncodedKeys(encKeyStr, hmacKeyStr);
+  }
+
+  @SuppressWarnings("unchecked")
+  private static JSONArray keyBundleToArray(KeyBundle bundle) {
+    // Generate JSON.
+    JSONArray keysArray = new JSONArray();
+    keysArray.add(new String(Base64.encodeBase64(bundle.getEncryptionKey())));
+    keysArray.add(new String(Base64.encodeBase64(bundle.getHMACKey())));
+    return keysArray;
+  }
+
+  private ExtendedJSONObject asRecordContents() throws NoCollectionKeysSetException {
+    ExtendedJSONObject json = new ExtendedJSONObject();
+    json.put("id", "keys");
+    json.put("collection", "crypto");
+    json.put("default", keyBundleToArray(this.defaultKeyBundle()));
+    ExtendedJSONObject colls = new ExtendedJSONObject();
+    for (Entry<String, KeyBundle> collKey : collectionKeyBundles.entrySet()) {
+      colls.put(collKey.getKey(), keyBundleToArray(collKey.getValue()));
+    }
+    json.put("collections", colls);
+    return json;
+  }
+
+  public CryptoRecord asCryptoRecord() throws NoCollectionKeysSetException {
+    ExtendedJSONObject payload = this.asRecordContents();
+    CryptoRecord record = new CryptoRecord(payload);
+    record.collection = "crypto";
+    record.guid       = "keys";
+    record.deleted    = false;
+    return record;
+  }
+
+  /**
+   * Set my key bundle and collection keys with the given key bundle and data
+   * (possibly decrypted) from the given record.
+   *
+   * @param keys
+   *          A "crypto/keys" <code>CryptoRecord</code>, encrypted with
+   *          <code>syncKeyBundle</code> if <code>syncKeyBundle</code> is non-null.
+   * @param syncKeyBundle
+   *          If non-null, the sync key bundle to decrypt <code>keys</code> with.
+   */
+  public void setKeyPairsFromWBO(CryptoRecord keys, KeyBundle syncKeyBundle)
+      throws CryptoException, IOException, NonObjectJSONException {
+    if (keys == null) {
+      throw new IllegalArgumentException("cannot set key pairs from null record");
+    }
+    if (syncKeyBundle != null) {
+      keys.keyBundle = syncKeyBundle;
+      keys.decrypt();
+    }
+    ExtendedJSONObject cleartext = keys.payload;
+    KeyBundle defaultKey = arrayToKeyBundle((JSONArray) cleartext.get("default"));
+
+    ExtendedJSONObject collections = cleartext.getObject("collections");
+    HashMap<String, KeyBundle> collectionKeys = new HashMap<String, KeyBundle>();
+    for (Entry<String, Object> pair : collections.entrySet()) {
+      KeyBundle bundle = arrayToKeyBundle((JSONArray) pair.getValue());
+      collectionKeys.put(pair.getKey(), bundle);
+    }
+
+    this.collectionKeyBundles.clear();
+    this.collectionKeyBundles.putAll(collectionKeys);
+    this.defaultKeyBundle     = defaultKey;
+  }
+
+  public void setKeyBundleForCollection(String collection, KeyBundle keys) {
+    this.collectionKeyBundles.put(collection, keys);
+  }
+
+  public void setDefaultKeyBundle(KeyBundle keys) {
+    this.defaultKeyBundle = keys;
+  }
+
+  public void clear() {
+    this.defaultKeyBundle = null;
+    this.collectionKeyBundles.clear();
+  }
+
+  /**
+   * Return set of collections where key is either missing from one collection
+   * or not the same in both collections.
+   * <p>
+   * Does not check for different default keys.
+   */
+  public static Set<String> differences(CollectionKeys a, CollectionKeys b) {
+    Set<String> differences = new HashSet<String>();
+    Set<String> collections = new HashSet<String>(a.collectionKeyBundles.keySet());
+    collections.addAll(b.collectionKeyBundles.keySet());
+
+    // Iterate through one collection, collecting missing and differences.
+    for (String collection : collections) {
+      KeyBundle keyA;
+      KeyBundle keyB;
+      try {
+        keyA = a.keyBundleForCollection(collection); // Will return default key as appropriate.
+        keyB = b.keyBundleForCollection(collection); // Will return default key as appropriate.
+      } catch (NoCollectionKeysSetException e) {
+        differences.add(collection);
+        continue;
+      }
+      // keyA and keyB are not null at this point.
+      if (!keyA.equals(keyB)) {
+        differences.add(collection);
+      }
+    }
+
+    return differences;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (!(o instanceof CollectionKeys)) {
+      return false;
+    }
+    CollectionKeys other = (CollectionKeys) o;
+    try {
+      // It would be nice to use map equality here, but there can be map entries
+      // where the key is the default key that should compare equal to a missing
+      // map entry. Therefore, we always compute the set of differences.
+      return defaultKeyBundle().equals(other.defaultKeyBundle()) &&
+             CollectionKeys.differences(this, other).isEmpty();
+    } catch (NoCollectionKeysSetException e) {
+      // If either default key bundle is not set, we'll say the bundles are not equal.
+      return false;
+    }
+  }
+
+  @Override
+  public int hashCode() {
+    return super.hashCode();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CommandProcessor.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CommandProcessor.java
new file mode 100644
index 000000000..371603de5
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CommandProcessor.java
@@ -0,0 +1,261 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.android.ClientsDatabaseAccessor;
+import org.mozilla.gecko.sync.repositories.domain.ClientRecord;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Process commands received from Sync clients.
+ * <p>
+ * We need a command processor at two different times:
+ * <ol>
+ * <li>We execute commands during the "clients" engine stage of a Sync. Each
+ * command takes a <code>GlobalSession</code> instance as a parameter.</li>
+ * <li>We queue commands to be executed or propagated to other Sync clients
+ * during an activity completely unrelated to a sync</li>
+ * </ol>
+ * To provide a processor for both these time frames, we maintain a static
+ * long-lived singleton.
+ */
+public class CommandProcessor {
+  private static final String LOG_TAG = "Command";
+  private static final AtomicInteger currentId = new AtomicInteger();
+  protected ConcurrentHashMap<String, CommandRunner> commands = new ConcurrentHashMap<String, CommandRunner>();
+
+  private final static CommandProcessor processor = new CommandProcessor();
+
+  /**
+   * Get the global singleton command processor.
+   *
+   * @return the singleton processor.
+   */
+  public static CommandProcessor getProcessor() {
+    return processor;
+  }
+
+  public static class Command {
+    public final String commandType;
+    public final JSONArray args;
+    private List<String> argsList;
+
+    public Command(String commandType, JSONArray args) {
+      this.commandType = commandType;
+      this.args = args;
+    }
+
+    /**
+     * Get list of arguments as strings.  Individual arguments may be null.
+     *
+     * @return list of strings.
+     */
+    public synchronized List<String> getArgsList() {
+      if (argsList == null) {
+        ArrayList<String> argsList = new ArrayList<String>(args.size());
+
+        for (int i = 0; i < args.size(); i++) {
+          final Object arg = args.get(i);
+          if (arg == null) {
+            argsList.add(null);
+            continue;
+          }
+          argsList.add(arg.toString());
+        }
+        this.argsList = argsList;
+      }
+      return this.argsList;
+    }
+
+    @SuppressWarnings("unchecked")
+    public JSONObject asJSONObject() {
+      JSONObject out = new JSONObject();
+      out.put("command", this.commandType);
+      out.put("args", this.args);
+      return out;
+    }
+  }
+
+  /**
+   * Register a command.
+   * <p>
+   * Any existing registration is overwritten.
+   *
+   * @param commandType
+   *          the name of the command, i.e., "displayURI".
+   * @param command
+   *          the <code>CommandRunner</code> instance that should handle the
+   *          command.
+   */
+  public void registerCommand(String commandType, CommandRunner command) {
+    commands.put(commandType, command);
+  }
+
+  /**
+   * Process a command in the context of the given global session.
+   *
+   * @param session
+   *          the <code>GlobalSession</code> instance currently executing.
+   * @param unparsedCommand
+   *          command as a <code>ExtendedJSONObject</code> instance.
+   */
+  public void processCommand(final GlobalSession session, ExtendedJSONObject unparsedCommand) {
+    Command command = parseCommand(unparsedCommand);
+    if (command == null) {
+      Logger.debug(LOG_TAG, "Invalid command: " + unparsedCommand + " will not be processed.");
+      return;
+    }
+
+    CommandRunner executableCommand = commands.get(command.commandType);
+    if (executableCommand == null) {
+      Logger.debug(LOG_TAG, "Command \"" + command.commandType + "\" not registered and will not be processed.");
+      return;
+    }
+
+    executableCommand.executeCommand(session, command.getArgsList());
+  }
+
+  /**
+   * Parse a JSON command into a ParsedCommand object for easier handling.
+   *
+   * @param unparsedCommand - command as ExtendedJSONObject
+   * @return - null if command is invalid, else return ParsedCommand with
+   *           no null attributes.
+   */
+  protected static Command parseCommand(ExtendedJSONObject unparsedCommand) {
+    String type = (String) unparsedCommand.get("command");
+    if (type == null) {
+      return null;
+    }
+
+    try {
+      JSONArray unparsedArgs = unparsedCommand.getArray("args");
+      if (unparsedArgs == null) {
+        return null;
+      }
+
+      return new Command(type, unparsedArgs);
+    } catch (NonArrayJSONException e) {
+      Logger.debug(LOG_TAG, "Unable to parse args array. Invalid command");
+      return null;
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  public void sendURIToClientForDisplay(String uri, String clientID, String title, String sender, Context context) {
+    Logger.info(LOG_TAG, "Sending URI to client " + clientID + ".");
+    if (Logger.LOG_PERSONAL_INFORMATION) {
+      Logger.pii(LOG_TAG, "URI is " + uri + "; title is '" + title + "'.");
+    }
+
+    final JSONArray args = new JSONArray();
+    args.add(uri);
+    args.add(sender);
+    args.add(title);
+
+    final Command displayURICommand = new Command("displayURI", args);
+    this.sendCommand(clientID, displayURICommand, context);
+  }
+
+  /**
+   * Validates and sends a command to a client or all clients.
+   *
+   * Calling this does not actually sync the command data to the server. If the
+   * client already has the command/args pair, it won't receive a duplicate
+   * command.
+   *
+   * @param clientID
+   *        Client ID to send command to. If null, send to all remote
+   *        clients.
+   * @param command
+   *        Command to invoke on remote clients
+   */
+  public void sendCommand(String clientID, Command command, Context context) {
+    Logger.debug(LOG_TAG, "In sendCommand.");
+
+    CommandRunner commandData = commands.get(command.commandType);
+
+    // Don't send commands that we don't know about.
+    if (commandData == null) {
+      Logger.error(LOG_TAG, "Unknown command to send: " + command);
+      return;
+    }
+
+    // Don't send a command with the wrong number of arguments.
+    if (!commandData.argumentsAreValid(command.getArgsList())) {
+      Logger.error(LOG_TAG, "Expected " + commandData.argCount + " args for '" +
+                   command + "', but got " + command.args);
+      return;
+    }
+
+    if (clientID != null) {
+      this.sendCommandToClient(clientID, command, context);
+      return;
+    }
+
+    ClientsDatabaseAccessor db = new ClientsDatabaseAccessor(context);
+    try {
+      Map<String, ClientRecord> clientMap = db.fetchAllClients();
+      for (ClientRecord client : clientMap.values()) {
+        this.sendCommandToClient(client.guid, command, context);
+      }
+    } catch (NullCursorException e) {
+      Logger.error(LOG_TAG, "NullCursorException when fetching all GUIDs");
+    } finally {
+      db.close();
+    }
+  }
+
+  protected void sendCommandToClient(String clientID, Command command, Context context) {
+    Logger.info(LOG_TAG, "Sending " + command.commandType + " to " + clientID);
+
+    ClientsDatabaseAccessor db = new ClientsDatabaseAccessor(context);
+    try {
+      db.store(clientID, command);
+    } catch (NullCursorException e) {
+      Logger.error(LOG_TAG, "NullCursorException: Unable to send command.");
+    } finally {
+      db.close();
+    }
+  }
+
+  public static void displayURI(final List<String> args, final Context context) {
+    // We trust the client sender that these exist.
+    final String uri = args.get(0);
+    final String clientId = args.get(1);
+    Logger.pii(LOG_TAG, "Received a URI for display: " + uri + " from " + clientId);
+
+    if (uri == null) {
+      Logger.pii(LOG_TAG, "URI is null – ignoring");
+      return;
+    }
+
+    String title = null;
+    if (args.size() == 3) {
+      title = args.get(2);
+    }
+
+    final Intent sendTabNotificationIntent = new Intent();
+    sendTabNotificationIntent.setClassName(context, BrowserContract.TAB_RECEIVED_SERVICE_CLASS_NAME);
+    sendTabNotificationIntent.setData(Uri.parse(uri));
+    sendTabNotificationIntent.putExtra(Intent.EXTRA_TITLE, title);
+    sendTabNotificationIntent.putExtra(BrowserContract.EXTRA_CLIENT_GUID, clientId);
+    final ComponentName componentName = context.startService(sendTabNotificationIntent);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CommandRunner.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CommandRunner.java
new file mode 100644
index 000000000..c7a0f1762
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CommandRunner.java
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.util.List;
+
+public abstract class CommandRunner {
+  public final int argCount;
+
+  public CommandRunner(int argCount) {
+    this.argCount = argCount;
+  }
+
+  public abstract void executeCommand(GlobalSession session, List<String> args);
+
+  public boolean argumentsAreValid(List<String> args) {
+    return args != null &&
+           args.size() == argCount;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CredentialException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CredentialException.java
new file mode 100644
index 000000000..f9004e14c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CredentialException.java
@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.SyncResult;
+
+/**
+ * There was a problem with the Sync account's credentials: bad username,
+ * missing password, malformed sync key, etc.
+ */
+public abstract class CredentialException extends SyncException {
+  private static final long serialVersionUID = 833010553314100538L;
+
+  public CredentialException() {
+    super();
+  }
+
+  public CredentialException(final Throwable e) {
+    super(e);
+  }
+
+  @Override
+  public void updateStats(GlobalSession globalSession, SyncResult syncResult) {
+    syncResult.stats.numAuthExceptions += 1;
+  }
+
+  /**
+   * No credentials at all.
+   */
+  public static class MissingAllCredentialsException extends CredentialException {
+    private static final long serialVersionUID = 3763937096217604611L;
+
+    public MissingAllCredentialsException() {
+      super();
+    }
+
+    public MissingAllCredentialsException(final Throwable e) {
+      super(e);
+    }
+  }
+
+  /**
+   * Some credential is missing.
+   */
+  public static class MissingCredentialException extends CredentialException {
+    private static final long serialVersionUID = -7543031216547596248L;
+
+    public final String missingCredential;
+
+    public MissingCredentialException(final String missingCredential) {
+      this.missingCredential = missingCredential;
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CryptoRecord.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CryptoRecord.java
new file mode 100644
index 000000000..65563d344
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/CryptoRecord.java
@@ -0,0 +1,255 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+
+import org.json.simple.JSONObject;
+import org.mozilla.apache.commons.codec.binary.Base64;
+import org.mozilla.gecko.sync.crypto.CryptoException;
+import org.mozilla.gecko.sync.crypto.CryptoInfo;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.crypto.MissingCryptoInputException;
+import org.mozilla.gecko.sync.crypto.NoKeyBundleException;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+import org.mozilla.gecko.sync.repositories.domain.RecordParseException;
+
+/**
+ * A Sync crypto record has:
+ *
+ * <ul>
+ * <li>a collection of fields which are not encrypted (id and collection);</il>
+ * <li>a set of metadata fields (index, modified, ttl);</il>
+ * <li>a payload, which is encrypted and decrypted on request.</il>
+ * </ul>
+ *
+ * The payload flips between being a blob of JSON with hmac/IV/ciphertext
+ * attributes and the cleartext itself.
+ *
+ * Until there's some benefit to the abstraction, we're simply going to call
+ * this <code>CryptoRecord</code>.
+ *
+ * <code>CryptoRecord</code> uses <code>CryptoInfo</code> to do the actual
+ * encryption and decryption.
+ */
+public class CryptoRecord extends Record {
+
+  // JSON related constants.
+  private static final String KEY_ID         = "id";
+  private static final String KEY_COLLECTION = "collection";
+  private static final String KEY_PAYLOAD    = "payload";
+  private static final String KEY_MODIFIED   = "modified";
+  private static final String KEY_SORTINDEX  = "sortindex";
+  private static final String KEY_TTL        = "ttl";
+  private static final String KEY_CIPHERTEXT = "ciphertext";
+  private static final String KEY_HMAC       = "hmac";
+  private static final String KEY_IV         = "IV";
+
+  /**
+   * Helper method for doing actual decryption.
+   *
+   * Input: JSONObject containing a valid payload (cipherText, IV, HMAC),
+   * KeyBundle with keys for decryption. Output: byte[] clearText
+   * @throws CryptoException
+   * @throws UnsupportedEncodingException
+   */
+  private static byte[] decryptPayload(ExtendedJSONObject payload, KeyBundle keybundle) throws CryptoException, UnsupportedEncodingException {
+    byte[] ciphertext = Base64.decodeBase64(((String) payload.get(KEY_CIPHERTEXT)).getBytes("UTF-8"));
+    byte[] iv         = Base64.decodeBase64(((String) payload.get(KEY_IV)).getBytes("UTF-8"));
+    byte[] hmac       = Utils.hex2Byte((String) payload.get(KEY_HMAC));
+
+    return CryptoInfo.decrypt(ciphertext, iv, hmac, keybundle).getMessage();
+  }
+
+  // The encrypted JSON body object.
+  // The decrypted JSON body object. Fields are copied from `body`.
+
+  public ExtendedJSONObject payload;
+  public KeyBundle   keyBundle;
+
+  /**
+   * Don't forget to set cleartext or body!
+   */
+  public CryptoRecord() {
+    super(null, null, 0, false);
+  }
+
+  public CryptoRecord(ExtendedJSONObject payload) {
+    super(null, null, 0, false);
+    if (payload == null) {
+      throw new IllegalArgumentException(
+          "No payload provided to CryptoRecord constructor.");
+    }
+    this.payload = payload;
+  }
+
+  public CryptoRecord(String jsonString) throws IOException, NonObjectJSONException {
+
+    this(new ExtendedJSONObject(jsonString));
+  }
+
+  /**
+   * Create a new CryptoRecord with the same metadata as an existing record.
+   *
+   * @param source
+   */
+  public CryptoRecord(Record source) {
+    super(source.guid, source.collection, source.lastModified, source.deleted);
+    this.ttl = source.ttl;
+  }
+
+  @Override
+  public Record copyWithIDs(String guid, long androidID) {
+    CryptoRecord out = new CryptoRecord(this);
+    out.guid         = guid;
+    out.androidID    = androidID;
+    out.sortIndex    = this.sortIndex;
+    out.ttl          = this.ttl;
+    out.payload      = (this.payload == null) ? null : new ExtendedJSONObject(this.payload.object);
+    out.keyBundle    = this.keyBundle;    // TODO: copy me?
+    return out;
+  }
+
+  /**
+   * Take a whole record as JSON -- i.e., something like
+   *
+   *   {"payload": "{...}", "id":"foobarbaz"}
+   *
+   * and turn it into a CryptoRecord object.
+   *
+   * @param jsonRecord
+   * @return
+   *        A CryptoRecord that encapsulates the provided record.
+   *
+   * @throws NonObjectJSONException
+   * @throws IOException
+   */
+  public static CryptoRecord fromJSONRecord(String jsonRecord)
+      throws NonObjectJSONException, IOException, RecordParseException {
+    byte[] bytes = jsonRecord.getBytes("UTF-8");
+    ExtendedJSONObject object = ExtendedJSONObject.parseUTF8AsJSONObject(bytes);
+
+    return CryptoRecord.fromJSONRecord(object);
+  }
+
+  // TODO: defensive programming.
+  public static CryptoRecord fromJSONRecord(ExtendedJSONObject jsonRecord)
+      throws IOException, NonObjectJSONException, RecordParseException {
+    String id                  = (String) jsonRecord.get(KEY_ID);
+    String collection          = (String) jsonRecord.get(KEY_COLLECTION);
+    String jsonEncodedPayload  = (String) jsonRecord.get(KEY_PAYLOAD);
+
+    ExtendedJSONObject payload = new ExtendedJSONObject(jsonEncodedPayload);
+
+    CryptoRecord record = new CryptoRecord(payload);
+    record.guid         = id;
+    record.collection   = collection;
+    if (jsonRecord.containsKey(KEY_MODIFIED)) {
+      Long timestamp = jsonRecord.getTimestamp(KEY_MODIFIED);
+      if (timestamp == null) {
+        throw new RecordParseException("timestamp could not be parsed");
+      }
+      record.lastModified = timestamp;
+    }
+    if (jsonRecord.containsKey(KEY_SORTINDEX)) {
+      // getLong tries to cast to Long, and might return null. We catch all
+      // exceptions, just to be safe.
+      try {
+        record.sortIndex = jsonRecord.getLong(KEY_SORTINDEX);
+      } catch (Exception e) {
+        throw new RecordParseException("timestamp could not be parsed");
+      }
+    }
+    if (jsonRecord.containsKey(KEY_TTL)) {
+      // TTLs are never returned by the sync server, so should never be true if
+      // the record was fetched.
+      try {
+        record.ttl = jsonRecord.getLong(KEY_TTL);
+      } catch (Exception e) {
+        throw new RecordParseException("TTL could not be parsed");
+      }
+    }
+    // TODO: deleted?
+    return record;
+  }
+
+  public void setKeyBundle(KeyBundle bundle) {
+    this.keyBundle = bundle;
+  }
+
+  public CryptoRecord decrypt() throws CryptoException, IOException, NonObjectJSONException {
+    if (keyBundle == null) {
+      throw new NoKeyBundleException();
+    }
+
+    // Check that payload contains all pieces for crypto.
+    if (!payload.containsKey(KEY_CIPHERTEXT) ||
+        !payload.containsKey(KEY_IV) ||
+        !payload.containsKey(KEY_HMAC)) {
+      throw new MissingCryptoInputException();
+    }
+
+    // There's no difference between handling the crypto/keys object and
+    // anything else; we just get this.keyBundle from a different source.
+    byte[] cleartext = decryptPayload(payload, keyBundle);
+    payload = ExtendedJSONObject.parseUTF8AsJSONObject(cleartext);
+    return this;
+  }
+
+  public CryptoRecord encrypt() throws CryptoException, UnsupportedEncodingException {
+    if (this.keyBundle == null) {
+      throw new NoKeyBundleException();
+    }
+    String cleartext = payload.toJSONString();
+    byte[] cleartextBytes = cleartext.getBytes("UTF-8");
+    CryptoInfo info = CryptoInfo.encrypt(cleartextBytes, keyBundle);
+    String message = new String(Base64.encodeBase64(info.getMessage()));
+    String iv      = new String(Base64.encodeBase64(info.getIV()));
+    String hmac    = Utils.byte2Hex(info.getHMAC());
+    ExtendedJSONObject ciphertext = new ExtendedJSONObject();
+    ciphertext.put(KEY_CIPHERTEXT, message);
+    ciphertext.put(KEY_HMAC, hmac);
+    ciphertext.put(KEY_IV, iv);
+    this.payload = ciphertext;
+    return this;
+  }
+
+  @Override
+  public void initFromEnvelope(CryptoRecord payload) {
+    throw new IllegalStateException("Can't do this with a CryptoRecord.");
+  }
+
+  @Override
+  public CryptoRecord getEnvelope() {
+    throw new IllegalStateException("Can't do this with a CryptoRecord.");
+  }
+
+  @Override
+  protected void populatePayload(ExtendedJSONObject payload) {
+    throw new IllegalStateException("Can't do this with a CryptoRecord.");
+  }
+
+  @Override
+  protected void initFromPayload(ExtendedJSONObject payload) {
+    throw new IllegalStateException("Can't do this with a CryptoRecord.");
+  }
+
+  // TODO: this only works with encrypted object, and has other limitations.
+  public JSONObject toJSONObject() {
+    ExtendedJSONObject o = new ExtendedJSONObject();
+    o.put(KEY_PAYLOAD, payload.toJSONString());
+    o.put(KEY_ID,      this.guid);
+    if (this.ttl > 0) {
+      o.put(KEY_TTL, this.ttl);
+    }
+    return o.object;
+  }
+
+  @Override
+  public String toJSONString() {
+    return toJSONObject().toJSONString();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/DelayedWorkTracker.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/DelayedWorkTracker.java
new file mode 100644
index 000000000..ddcb5411c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/DelayedWorkTracker.java
@@ -0,0 +1,69 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+/**
+ * A little class to allow us to maintain a count of extant
+ * things (in our case, callbacks that need to fire), and
+ * some work that we want done when that count hits 0.
+ *
+ * @author rnewman
+ *
+ */
+public class DelayedWorkTracker {
+  private static final String LOG_TAG = "DelayedWorkTracker";
+  protected Runnable workItem = null;
+  protected int outstandingCount = 0;
+
+  public int incrementOutstanding() {
+    Logger.trace(LOG_TAG, "Incrementing outstanding.");
+    synchronized(this) {
+      return ++outstandingCount;
+    }
+  }
+  public int decrementOutstanding() {
+    Logger.trace(LOG_TAG, "Decrementing outstanding.");
+    Runnable job = null;
+    int count;
+    synchronized(this) {
+      if ((count = --outstandingCount) == 0 &&
+          workItem != null) {
+        job = workItem;
+        workItem = null;
+      } else {
+        return count;
+      }
+    }
+    job.run();
+    // In case it's changed.
+    return getOutstandingOperations();
+  }
+  public int getOutstandingOperations() {
+    synchronized(this) {
+      return outstandingCount;
+    }
+  }
+  public void delayWorkItem(Runnable item) {
+    Logger.trace(LOG_TAG, "delayWorkItem.");
+    boolean runnableNow = false;
+    synchronized(this) {
+      Logger.trace(LOG_TAG, "outstandingCount: " + outstandingCount);
+      if (outstandingCount == 0) {
+        runnableNow = true;
+      } else {
+        if (workItem != null) {
+          throw new IllegalStateException("Work item already set!");
+        }
+        workItem = item;
+      }
+    }
+    if (runnableNow) {
+      Logger.trace(LOG_TAG, "Running item now.");
+      item.run();
+    }
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/EngineSettings.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/EngineSettings.java
new file mode 100644
index 000000000..035816088
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/EngineSettings.java
@@ -0,0 +1,31 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+public class EngineSettings {
+  public final String syncID;
+  public final int version;
+
+  public EngineSettings(final String syncID, final int version) {
+    this.syncID = syncID;
+    this.version = version;
+  }
+
+  public EngineSettings(ExtendedJSONObject object) {
+    try {
+      this.syncID = object.getString("syncID");
+      this.version = object.getIntegerSafely("version");
+    } catch (Exception e ) {
+      throw new IllegalArgumentException(e);
+    }
+  }
+
+  public ExtendedJSONObject toJSONObject() {
+    ExtendedJSONObject json = new ExtendedJSONObject();
+    json.put("syncID", syncID);
+    json.put("version", version);
+    return json;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/ExtendedJSONObject.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/ExtendedJSONObject.java
new file mode 100644
index 000000000..f5fac0009
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/ExtendedJSONObject.java
@@ -0,0 +1,426 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+import org.mozilla.apache.commons.codec.binary.Base64;
+import org.mozilla.gecko.sync.UnexpectedJSONException.BadRequiredFieldJSONException;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.io.StringReader;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+/**
+ * Extend JSONObject to do little things, like, y'know, accessing members.
+ *
+ * @author rnewman
+ *
+ */
+public class ExtendedJSONObject {
+
+  public JSONObject object;
+
+  /**
+   * Return a <code>JSONParser</code> instance for immediate use.
+   * <p>
+   * <code>JSONParser</code> is not thread-safe, so we return a new instance
+   * each call. This is extremely inefficient in execution time and especially
+   * memory use -- each instance allocates a 16kb temporary buffer -- and we
+   * hope to improve matters eventually.
+   */
+  protected static JSONParser getJSONParser() {
+    return new JSONParser();
+  }
+
+  /**
+   * Parse a JSON encoded string.
+   *
+   * @param in <code>Reader</code> over a JSON-encoded input to parse; not
+   *            necessarily a JSON object.
+   * @return a regular Java <code>Object</code>.
+   * @throws ParseException
+   * @throws IOException
+   */
+  protected static Object parseRaw(Reader in) throws ParseException, IOException {
+    try {
+      return getJSONParser().parse(in);
+    } catch (Error e) {
+      // Don't be stupid, org.json.simple. Bug 1042929.
+      throw new ParseException(ParseException.ERROR_UNEXPECTED_EXCEPTION, e);
+    }
+  }
+
+  /**
+   * Parse a JSON encoded string.
+   * <p>
+   * You should prefer the streaming interface {@link #parseRaw(Reader)}.
+   *
+   * @param input JSON-encoded input string to parse; not necessarily a JSON object.
+   * @return a regular Java <code>Object</code>.
+   * @throws ParseException
+   */
+  protected static Object parseRaw(String input) throws ParseException {
+    try {
+      return getJSONParser().parse(input);
+    } catch (Error e) {
+      // Don't be stupid, org.json.simple. Bug 1042929.
+      throw new ParseException(ParseException.ERROR_UNEXPECTED_EXCEPTION, e);
+    }
+  }
+
+  /**
+   * Helper method to get a JSON array from a stream.
+   *
+   * @param in <code>Reader</code> over a JSON-encoded array to parse.
+   * @throws ParseException
+   * @throws IOException
+   * @throws NonArrayJSONException if the object is valid JSON, but not an array.
+   */
+  public static JSONArray parseJSONArray(Reader in)
+      throws IOException, ParseException, NonArrayJSONException {
+    Object o = parseRaw(in);
+
+    if (o == null) {
+      return null;
+    }
+
+    if (o instanceof JSONArray) {
+      return (JSONArray) o;
+    }
+
+    throw new NonArrayJSONException("value must be a JSON array");
+  }
+
+  /**
+   * Helper method to get a JSON array from a string.
+   * <p>
+   * You should prefer the stream interface {@link #parseJSONArray(Reader)}.
+   *
+   * @param jsonString input.
+   * @throws IOException
+   * @throws NonArrayJSONException if the object is invalid JSON or not an array.
+   */
+  public static JSONArray parseJSONArray(String jsonString)
+      throws IOException, NonArrayJSONException {
+    Object o = null;
+    try {
+      o = parseRaw(jsonString);
+    } catch (ParseException e) {
+      throw new NonArrayJSONException(e);
+    }
+
+    if (o == null) {
+      return null;
+    }
+
+    if (o instanceof JSONArray) {
+      return (JSONArray) o;
+    }
+
+    throw new NonArrayJSONException("value must be a JSON array");
+  }
+
+  /**
+   * Helper method to get a JSON object from a UTF-8 byte array.
+   *
+   * @param in UTF-8 bytes.
+   * @throws NonObjectJSONException if the object is not valid JSON or not an object.
+   * @throws IOException
+   */
+  public static ExtendedJSONObject parseUTF8AsJSONObject(byte[] in)
+      throws NonObjectJSONException, IOException {
+    return new ExtendedJSONObject(new String(in, "UTF-8"));
+  }
+
+  public ExtendedJSONObject() {
+    this.object = new JSONObject();
+  }
+
+  public ExtendedJSONObject(JSONObject o) {
+    this.object = o;
+  }
+
+  public ExtendedJSONObject(Reader in) throws IOException, NonObjectJSONException {
+    if (in == null) {
+      this.object = new JSONObject();
+      return;
+    }
+
+    Object obj = null;
+    try {
+      obj = parseRaw(in);
+    } catch (ParseException e) {
+      throw new NonObjectJSONException(e);
+    }
+
+    if (obj instanceof JSONObject) {
+      this.object = ((JSONObject) obj);
+    } else {
+      throw new NonObjectJSONException("value must be a JSON object");
+    }
+  }
+
+  public ExtendedJSONObject(String jsonString) throws IOException, NonObjectJSONException {
+    this(jsonString == null ? null : new StringReader(jsonString));
+  }
+
+  @Override
+  public ExtendedJSONObject clone() {
+    return new ExtendedJSONObject((JSONObject) this.object.clone());
+  }
+
+  // Passthrough methods.
+  public Object get(String key) {
+    return this.object.get(key);
+  }
+
+  public long getLong(String key, long def) {
+    if (!object.containsKey(key)) {
+      return def;
+    }
+
+    Long val = getLong(key);
+    if (val == null) {
+      return def;
+    }
+    return val.longValue();
+  }
+
+  public Long getLong(String key) {
+    return (Long) this.get(key);
+  }
+
+  public String getString(String key) {
+    return (String) this.get(key);
+  }
+
+  public Boolean getBoolean(String key) {
+    return (Boolean) this.get(key);
+  }
+
+  /**
+   * Return an Integer if the value for this key is an Integer, Long, or String
+   * that can be parsed as a base 10 Integer.
+   * Passes through null.
+   *
+   * @throws NumberFormatException
+   */
+  public Integer getIntegerSafely(String key) throws NumberFormatException {
+    Object val = this.object.get(key);
+    if (val == null) {
+      return null;
+    }
+    if (val instanceof Integer) {
+      return (Integer) val;
+    }
+    if (val instanceof Long) {
+      return ((Long) val).intValue();
+    }
+    if (val instanceof String) {
+      return Integer.parseInt((String) val, 10);
+    }
+    throw new NumberFormatException("Expecting Integer, got " + val.getClass());
+  }
+
+  /**
+   * Return a server timestamp value as milliseconds since epoch.
+   *
+   * @param key
+   * @return A Long, or null if the value is non-numeric or doesn't exist.
+   */
+  public Long getTimestamp(String key) {
+    Object val = this.object.get(key);
+
+    // This is absurd.
+    if (val instanceof Double) {
+      double millis = ((Double) val) * 1000;
+      return Double.valueOf(millis).longValue();
+    }
+    if (val instanceof Float) {
+      double millis = ((Float) val).doubleValue() * 1000;
+      return Double.valueOf(millis).longValue();
+    }
+    if (val instanceof Number) {
+      // Must be an integral number.
+      return ((Number) val).longValue() * 1000;
+    }
+
+    return null;
+  }
+
+  public boolean containsKey(String key) {
+    return this.object.containsKey(key);
+  }
+
+  public String toJSONString() {
+    return this.object.toJSONString();
+  }
+
+  @Override
+  public String toString() {
+    return this.object.toString();
+  }
+
+  protected void putRaw(String key, Object value) {
+    @SuppressWarnings("unchecked")
+    Map<Object, Object> map = this.object;
+    map.put(key, value);
+  }
+
+  public void put(String key, String value) {
+    this.putRaw(key, value);
+  }
+
+  public void put(String key, boolean value) {
+    this.putRaw(key, value);
+  }
+
+  public void put(String key, long value) {
+    this.putRaw(key, value);
+  }
+
+  public void put(String key, int value) {
+    this.putRaw(key, value);
+  }
+
+  public void put(String key, ExtendedJSONObject value) {
+    this.putRaw(key, value);
+  }
+
+  public void put(String key, JSONArray value) {
+    this.putRaw(key, value);
+  }
+
+  @SuppressWarnings("unchecked")
+  public void putArray(String key, List<String> value) {
+    // Frustratingly inefficient, but there you have it.
+    final JSONArray jsonArray = new JSONArray();
+    jsonArray.addAll(value);
+    this.putRaw(key, jsonArray);
+  }
+
+  /**
+   * Remove key-value pair from JSONObject.
+   *
+   * @param key
+   *          to be removed.
+   * @return true if key exists and was removed, false otherwise.
+   */
+  public boolean remove(String key) {
+    Object res = this.object.remove(key);
+    return (res != null);
+  }
+
+  public ExtendedJSONObject getObject(String key) throws NonObjectJSONException {
+    Object o = this.object.get(key);
+    if (o == null) {
+      return null;
+    }
+    if (o instanceof ExtendedJSONObject) {
+      return (ExtendedJSONObject) o;
+    }
+    if (o instanceof JSONObject) {
+      return new ExtendedJSONObject((JSONObject) o);
+    }
+    throw new NonObjectJSONException("value must be a JSON object for key: " + key);
+  }
+
+  @SuppressWarnings("unchecked")
+  public Set<Entry<String, Object>> entrySet() {
+    return this.object.entrySet();
+  }
+
+  @SuppressWarnings("unchecked")
+  public Set<String> keySet() {
+    return this.object.keySet();
+  }
+
+  public org.json.simple.JSONArray getArray(String key) throws NonArrayJSONException {
+    Object o = this.object.get(key);
+    if (o == null) {
+      return null;
+    }
+    if (o instanceof JSONArray) {
+      return (JSONArray) o;
+    }
+    throw new NonArrayJSONException("key must be a JSON array: " + key);
+  }
+
+  public int size() {
+    return this.object.size();
+  }
+
+  @Override
+  public int hashCode() {
+    if (this.object == null) {
+      return getClass().hashCode();
+    }
+    return this.object.hashCode() ^ getClass().hashCode();
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (!(o instanceof ExtendedJSONObject)) {
+      return false;
+    }
+    if (o == this) {
+      return true;
+    }
+    ExtendedJSONObject other = (ExtendedJSONObject) o;
+    if (this.object == null) {
+      return other.object == null;
+    }
+    return this.object.equals(other.object);
+  }
+
+  /**
+   * Throw if keys are missing or values have wrong types.
+   *
+   * @param requiredFields list of required keys.
+   * @param requiredFieldClass class that values must be coercable to; may be null, which means don't check.
+   * @throws UnexpectedJSONException
+   */
+  public void throwIfFieldsMissingOrMisTyped(String[] requiredFields, Class<?> requiredFieldClass) throws BadRequiredFieldJSONException {
+    // Defensive as possible: verify object has expected key(s) with string value.
+    for (String k : requiredFields) {
+      Object value = get(k);
+      if (value == null) {
+        throw new BadRequiredFieldJSONException("Expected key not present in result: " + k);
+      }
+      if (requiredFieldClass != null && !(requiredFieldClass.isInstance(value))) {
+        throw new BadRequiredFieldJSONException("Value for key not an instance of " + requiredFieldClass + ": " + k);
+      }
+    }
+  }
+
+  /**
+   * Return a base64-encoded string value as a byte array.
+   */
+  public byte[] getByteArrayBase64(String key) {
+    String s = (String) this.object.get(key);
+    if (s == null) {
+      return null;
+    }
+    return Base64.decodeBase64(s);
+  }
+
+  /**
+   * Return a hex-encoded string value as a byte array.
+   */
+  public byte[] getByteArrayHex(String key) {
+    String s = (String) this.object.get(key);
+    if (s == null) {
+      return null;
+    }
+    return Utils.hex2Byte(s);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/GlobalSession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/GlobalSession.java
new file mode 100644
index 000000000..e28bbe4cc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/GlobalSession.java
@@ -0,0 +1,1167 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.Context;
+
+import org.json.simple.JSONArray;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.crypto.CryptoException;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.delegates.ClientsDataDelegate;
+import org.mozilla.gecko.sync.delegates.FreshStartDelegate;
+import org.mozilla.gecko.sync.delegates.GlobalSessionCallback;
+import org.mozilla.gecko.sync.delegates.JSONRecordFetchDelegate;
+import org.mozilla.gecko.sync.delegates.KeyUploadDelegate;
+import org.mozilla.gecko.sync.delegates.MetaGlobalDelegate;
+import org.mozilla.gecko.sync.delegates.WipeServerDelegate;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.BaseResource;
+import org.mozilla.gecko.sync.net.HttpResponseObserver;
+import org.mozilla.gecko.sync.net.SyncResponse;
+import org.mozilla.gecko.sync.net.SyncStorageRecordRequest;
+import org.mozilla.gecko.sync.net.SyncStorageRequest;
+import org.mozilla.gecko.sync.net.SyncStorageRequestDelegate;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+import org.mozilla.gecko.sync.stage.AndroidBrowserBookmarksServerSyncStage;
+import org.mozilla.gecko.sync.stage.AndroidBrowserHistoryServerSyncStage;
+import org.mozilla.gecko.sync.stage.CheckPreconditionsStage;
+import org.mozilla.gecko.sync.stage.CompletedStage;
+import org.mozilla.gecko.sync.stage.EnsureCrypto5KeysStage;
+import org.mozilla.gecko.sync.stage.FennecTabsServerSyncStage;
+import org.mozilla.gecko.sync.stage.FetchInfoCollectionsStage;
+import org.mozilla.gecko.sync.stage.FetchInfoConfigurationStage;
+import org.mozilla.gecko.sync.stage.FetchMetaGlobalStage;
+import org.mozilla.gecko.sync.stage.FormHistoryServerSyncStage;
+import org.mozilla.gecko.sync.stage.GlobalSyncStage;
+import org.mozilla.gecko.sync.stage.GlobalSyncStage.Stage;
+import org.mozilla.gecko.sync.stage.NoSuchStageException;
+import org.mozilla.gecko.sync.stage.PasswordsServerSyncStage;
+import org.mozilla.gecko.sync.stage.SyncClientsEngineStage;
+import org.mozilla.gecko.sync.stage.UploadMetaGlobalStage;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.EnumMap;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicLong;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.methods.HttpUriRequest;
+
+public class GlobalSession implements HttpResponseObserver {
+  private static final String LOG_TAG = "GlobalSession";
+
+  public static final long STORAGE_VERSION = 5;
+
+  public SyncConfiguration config = null;
+
+  protected Map<Stage, GlobalSyncStage> stages;
+  public Stage currentState = Stage.idle;
+
+  public final GlobalSessionCallback callback;
+  protected final Context context;
+  protected final ClientsDataDelegate clientsDelegate;
+
+  /**
+   * Map from engine name to new settings for an updated meta/global record.
+   * Engines to remove will have <code>null</code> EngineSettings.
+   */
+  public final Map<String, EngineSettings> enginesToUpdate = new HashMap<String, EngineSettings>();
+
+   /*
+   * Key accessors.
+   */
+  public KeyBundle keyBundleForCollection(String collection) throws NoCollectionKeysSetException {
+    return config.getCollectionKeys().keyBundleForCollection(collection);
+  }
+
+  /*
+   * Config passthrough for convenience.
+   */
+  public AuthHeaderProvider getAuthHeaderProvider() {
+    return config.getAuthHeaderProvider();
+  }
+
+  public URI wboURI(String collection, String id) throws URISyntaxException {
+    return config.wboURI(collection, id);
+  }
+
+  public GlobalSession(SyncConfiguration config,
+                       GlobalSessionCallback callback,
+                       Context context,
+                       ClientsDataDelegate clientsDelegate)
+    throws SyncConfigurationException, IllegalArgumentException, IOException, NonObjectJSONException {
+
+    if (callback == null) {
+      throw new IllegalArgumentException("Must provide a callback to GlobalSession constructor.");
+    }
+
+    this.callback        = callback;
+    this.context         = context;
+    this.clientsDelegate = clientsDelegate;
+
+    this.config = config;
+    registerCommands();
+    prepareStages();
+
+    if (config.stagesToSync == null) {
+      Logger.info(LOG_TAG, "No stages to sync specified; defaulting to all valid engine names.");
+      config.stagesToSync = Collections.unmodifiableCollection(SyncConfiguration.validEngineNames());
+    }
+
+    // TODO: data-driven plan for the sync, referring to prepareStages.
+  }
+
+  /**
+   * Register commands this global session knows how to process.
+   * <p>
+   * Re-registering a command overwrites any existing registration.
+   */
+  protected static void registerCommands() {
+    final CommandProcessor processor = CommandProcessor.getProcessor();
+
+    processor.registerCommand("resetEngine", new CommandRunner(1) {
+      @Override
+      public void executeCommand(final GlobalSession session, List<String> args) {
+        HashSet<String> names = new HashSet<String>();
+        names.add(args.get(0));
+        session.resetStagesByName(names);
+      }
+    });
+
+    processor.registerCommand("resetAll", new CommandRunner(0) {
+      @Override
+      public void executeCommand(final GlobalSession session, List<String> args) {
+        session.resetAllStages();
+      }
+    });
+
+    processor.registerCommand("wipeEngine", new CommandRunner(1) {
+      @Override
+      public void executeCommand(final GlobalSession session, List<String> args) {
+        HashSet<String> names = new HashSet<String>();
+        names.add(args.get(0));
+        session.wipeStagesByName(names);
+      }
+    });
+
+    processor.registerCommand("wipeAll", new CommandRunner(0) {
+      @Override
+      public void executeCommand(final GlobalSession session, List<String> args) {
+        session.wipeAllStages();
+      }
+    });
+
+    processor.registerCommand("displayURI", new CommandRunner(3) {
+      @Override
+      public void executeCommand(final GlobalSession session, List<String> args) {
+        CommandProcessor.displayURI(args, session.getContext());
+      }
+    });
+  }
+
+  protected void prepareStages() {
+    Map<Stage, GlobalSyncStage> stages = new EnumMap<Stage, GlobalSyncStage>(Stage.class);
+
+    stages.put(Stage.checkPreconditions,      new CheckPreconditionsStage());
+    stages.put(Stage.fetchInfoCollections,    new FetchInfoCollectionsStage());
+    stages.put(Stage.fetchMetaGlobal,         new FetchMetaGlobalStage());
+    stages.put(Stage.fetchInfoConfiguration,  new FetchInfoConfigurationStage(
+            config.infoConfigurationURL(), getAuthHeaderProvider()));
+    stages.put(Stage.ensureKeysStage,         new EnsureCrypto5KeysStage());
+
+    stages.put(Stage.syncClientsEngine,       new SyncClientsEngineStage());
+
+    stages.put(Stage.syncTabs,                new FennecTabsServerSyncStage());
+    stages.put(Stage.syncPasswords,           new PasswordsServerSyncStage());
+    stages.put(Stage.syncBookmarks,           new AndroidBrowserBookmarksServerSyncStage());
+    stages.put(Stage.syncHistory,             new AndroidBrowserHistoryServerSyncStage());
+    stages.put(Stage.syncFormHistory,         new FormHistoryServerSyncStage());
+
+    stages.put(Stage.uploadMetaGlobal,        new UploadMetaGlobalStage());
+    stages.put(Stage.completed,               new CompletedStage());
+
+    this.stages = Collections.unmodifiableMap(stages);
+  }
+
+  public GlobalSyncStage getSyncStageByName(String name) throws NoSuchStageException {
+    return getSyncStageByName(Stage.byName(name));
+  }
+
+  public GlobalSyncStage getSyncStageByName(Stage next) throws NoSuchStageException {
+    GlobalSyncStage stage = stages.get(next);
+    if (stage == null) {
+      throw new NoSuchStageException(next);
+    }
+    return stage;
+  }
+
+  public Collection<GlobalSyncStage> getSyncStagesByEnum(Collection<Stage> enums) {
+    ArrayList<GlobalSyncStage> out = new ArrayList<GlobalSyncStage>();
+    for (Stage name : enums) {
+      try {
+        GlobalSyncStage stage = this.getSyncStageByName(name);
+        out.add(stage);
+      } catch (NoSuchStageException e) {
+        Logger.warn(LOG_TAG, "Unable to find stage with name " + name);
+      }
+    }
+    return out;
+  }
+
+  public Collection<GlobalSyncStage> getSyncStagesByName(Collection<String> names) {
+    ArrayList<GlobalSyncStage> out = new ArrayList<GlobalSyncStage>();
+    for (String name : names) {
+      try {
+        GlobalSyncStage stage = this.getSyncStageByName(name);
+        out.add(stage);
+      } catch (NoSuchStageException e) {
+        Logger.warn(LOG_TAG, "Unable to find stage with name " + name);
+      }
+    }
+    return out;
+  }
+
+  /**
+   * Advance and loop around the stages of a sync.
+   * @param current
+   * @return
+   *        The next stage to execute.
+   */
+  public static Stage nextStage(Stage current) {
+    int index = current.ordinal() + 1;
+    int max   = Stage.completed.ordinal() + 1;
+    return Stage.values()[index % max];
+  }
+
+  /**
+   * Move to the next stage in the syncing process.
+   */
+  public void advance() {
+    // If we have a backoff, request a backoff and don't advance to next stage.
+    long existingBackoff = largestBackoffObserved.get();
+    if (existingBackoff > 0) {
+      this.abort(null, "Aborting sync because of backoff of " + existingBackoff + " milliseconds.");
+      return;
+    }
+
+    this.callback.handleStageCompleted(this.currentState, this);
+    Stage next = nextStage(this.currentState);
+    GlobalSyncStage nextStage;
+    try {
+      nextStage = this.getSyncStageByName(next);
+    } catch (NoSuchStageException e) {
+      this.abort(e, "No such stage " + next);
+      return;
+    }
+    this.currentState = next;
+    Logger.info(LOG_TAG, "Running next stage " + next + " (" + nextStage + ")...");
+    try {
+      nextStage.execute(this);
+    } catch (Exception ex) {
+      Logger.warn(LOG_TAG, "Caught exception " + ex + " running stage " + next);
+      this.abort(ex, "Uncaught exception in stage.");
+      return;
+    }
+  }
+
+  public Context getContext() {
+    return this.context;
+  }
+
+  /**
+   * Begin a sync.
+   * <p>
+   * The caller is responsible for:
+   * <ul>
+   * <li>Verifying that any backoffs/minimum next sync requests are respected.</li>
+   * <li>Ensuring that the device is online.</li>
+   * <li>Ensuring that dependencies are ready.</li>
+   * </ul>
+   *
+   * @throws AlreadySyncingException
+   */
+  public void start() throws AlreadySyncingException {
+    if (this.currentState != GlobalSyncStage.Stage.idle) {
+      throw new AlreadySyncingException(this.currentState);
+    }
+    installAsHttpResponseObserver(); // Uninstalled by completeSync or abort.
+    this.advance();
+  }
+
+  /**
+   * Stop this sync and start again.
+   * @throws AlreadySyncingException
+   */
+  protected void restart() throws AlreadySyncingException {
+    this.currentState = GlobalSyncStage.Stage.idle;
+    if (callback.shouldBackOffStorage()) {
+      this.callback.handleAborted(this, "Told to back off.");
+      return;
+    }
+    this.start();
+  }
+
+  /**
+   * We're finished (aborted or succeeded): release resources.
+   */
+  protected void cleanUp() {
+    uninstallAsHttpResponseObserver();
+    this.stages = null;
+  }
+
+  public void completeSync() {
+    cleanUp();
+    this.currentState = GlobalSyncStage.Stage.idle;
+    this.callback.handleSuccess(this);
+  }
+
+  /**
+   * Record that an updated meta/global record should be uploaded with the given
+   * settings for the given engine.
+   *
+   * @param engineName engine to update.
+   * @param engineSettings new syncID and version.
+   */
+  public void recordForMetaGlobalUpdate(String engineName, EngineSettings engineSettings) {
+    enginesToUpdate.put(engineName, engineSettings);
+  }
+
+  /**
+   * Record that an updated meta/global record should be uploaded without the
+   * given engine name.
+   *
+   * @param engineName
+   *          engine to remove.
+   */
+  public void removeEngineFromMetaGlobal(String engineName) {
+    enginesToUpdate.put(engineName, null);
+  }
+
+  public boolean hasUpdatedMetaGlobal() {
+    if (enginesToUpdate.isEmpty()) {
+      Logger.info(LOG_TAG, "Not uploading updated meta/global record since there are no engines requesting upload.");
+      return false;
+    }
+
+    if (Logger.shouldLogVerbose(LOG_TAG)) {
+      Logger.trace(LOG_TAG, "Uploading updated meta/global record since there are engine changes to meta/global.");
+      Logger.trace(LOG_TAG, "Engines requesting update [" + Utils.toCommaSeparatedString(enginesToUpdate.keySet()) + "]");
+    }
+
+    return true;
+  }
+
+  public void updateMetaGlobalInPlace() {
+    config.metaGlobal.declined = this.declinedEngineNames();
+    ExtendedJSONObject engines = config.metaGlobal.getEngines();
+    for (Entry<String, EngineSettings> pair : enginesToUpdate.entrySet()) {
+      if (pair.getValue() == null) {
+        engines.remove(pair.getKey());
+      } else {
+        engines.put(pair.getKey(), pair.getValue().toJSONObject());
+      }
+    }
+
+    enginesToUpdate.clear();
+  }
+
+  /**
+   * Synchronously upload an updated meta/global.
+   * <p>
+   * All problems are logged and ignored.
+   */
+  public void uploadUpdatedMetaGlobal() {
+    updateMetaGlobalInPlace();
+
+    Logger.debug(LOG_TAG, "Uploading updated meta/global record.");
+    final Object monitor = new Object();
+
+    Runnable doUpload = new Runnable() {
+      @Override
+      public void run() {
+        config.metaGlobal.upload(new MetaGlobalDelegate() {
+          @Override
+          public void handleSuccess(MetaGlobal global, SyncStorageResponse response) {
+            Logger.info(LOG_TAG, "Successfully uploaded updated meta/global record.");
+            // Engine changes are stored as diffs, so update enabled engines in config to match uploaded meta/global.
+            config.enabledEngineNames = config.metaGlobal.getEnabledEngineNames();
+            // Clear userSelectedEngines because they are updated in config and meta/global.
+            config.userSelectedEngines = null;
+
+            synchronized (monitor) {
+              monitor.notify();
+            }
+          }
+
+          @Override
+          public void handleMissing(MetaGlobal global, SyncStorageResponse response) {
+            Logger.warn(LOG_TAG, "Got 404 missing uploading updated meta/global record; shouldn't happen.  Ignoring.");
+            synchronized (monitor) {
+              monitor.notify();
+            }
+          }
+
+          @Override
+          public void handleFailure(SyncStorageResponse response) {
+            Logger.warn(LOG_TAG, "Failed to upload updated meta/global record; ignoring.");
+            synchronized (monitor) {
+              monitor.notify();
+            }
+          }
+
+          @Override
+          public void handleError(Exception e) {
+            Logger.warn(LOG_TAG, "Got exception trying to upload updated meta/global record; ignoring.", e);
+            synchronized (monitor) {
+              monitor.notify();
+            }
+          }
+        });
+      }
+    };
+
+    final Thread upload = new Thread(doUpload);
+    synchronized (monitor) {
+      try {
+        upload.start();
+        monitor.wait();
+        Logger.debug(LOG_TAG, "Uploaded updated meta/global record.");
+      } catch (InterruptedException e) {
+        Logger.error(LOG_TAG, "Uploading updated meta/global interrupted; continuing.");
+      }
+    }
+  }
+
+
+  public void abort(Exception e, String reason) {
+    Logger.warn(LOG_TAG, "Aborting sync: " + reason, e);
+    cleanUp();
+    long existingBackoff = largestBackoffObserved.get();
+    if (existingBackoff > 0) {
+      callback.requestBackoff(existingBackoff);
+    }
+    if (!(e instanceof HTTPFailureException)) {
+      //  e is null, or we aborted for a non-HTTP reason; okay to upload new meta/global record.
+      if (this.hasUpdatedMetaGlobal()) {
+        this.uploadUpdatedMetaGlobal(); // Only logs errors; does not call abort.
+      }
+    }
+    this.callback.handleError(this, e);
+  }
+
+  public void handleHTTPError(SyncStorageResponse response, String reason) {
+    // TODO: handling of 50x (backoff), 401 (node reassignment or auth error).
+    // Fall back to aborting.
+    Logger.warn(LOG_TAG, "Aborting sync due to HTTP " + response.getStatusCode());
+    this.interpretHTTPFailure(response.httpResponse());
+    this.abort(new HTTPFailureException(response), reason);
+  }
+
+  /**
+   * Perform appropriate backoff etc. extraction.
+   */
+  public void interpretHTTPFailure(HttpResponse response) {
+    // TODO: handle permanent rejection.
+    long responseBackoff = (new SyncResponse(response)).totalBackoffInMilliseconds();
+    if (responseBackoff > 0) {
+      callback.requestBackoff(responseBackoff);
+    }
+
+    if (response.getStatusLine() != null) {
+      final int statusCode = response.getStatusLine().getStatusCode();
+      switch(statusCode) {
+
+      case 400:
+        SyncStorageResponse storageResponse = new SyncStorageResponse(response);
+        this.interpretHTTPBadRequestBody(storageResponse);
+        break;
+
+      case 401:
+        /*
+         * Alert our callback we have a 401 on a cluster URL. This GlobalSession
+         * will fail, but the next one will fetch a new cluster URL and will
+         * distinguish between "node reassignment" and "user password changed".
+         */
+        callback.informUnauthorizedResponse(this, config.getClusterURL());
+        break;
+      }
+    }
+  }
+
+  protected void interpretHTTPBadRequestBody(final SyncStorageResponse storageResponse) {
+    try {
+      final String body = storageResponse.body();
+      if (body == null) {
+        return;
+      }
+      if (SyncStorageResponse.RESPONSE_CLIENT_UPGRADE_REQUIRED.equals(body)) {
+        callback.informUpgradeRequiredResponse(this);
+        return;
+      }
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Exception parsing HTTP 400 body.", e);
+    }
+  }
+
+  public void fetchInfoCollections(JSONRecordFetchDelegate callback) throws URISyntaxException {
+    final JSONRecordFetcher fetcher = new JSONRecordFetcher(config.infoCollectionsURL(), getAuthHeaderProvider());
+    fetcher.fetch(callback);
+  }
+
+  /**
+   * Upload new crypto/keys.
+   *
+   * @param keys
+   *          new keys.
+   * @param keyUploadDelegate
+   *          a delegate.
+   */
+  public void uploadKeys(final CollectionKeys keys,
+                         final KeyUploadDelegate keyUploadDelegate) {
+    SyncStorageRecordRequest request;
+    try {
+      request = new SyncStorageRecordRequest(this.config.keysURI());
+    } catch (URISyntaxException e) {
+      keyUploadDelegate.onKeyUploadFailed(e);
+      return;
+    }
+
+    request.delegate = new SyncStorageRequestDelegate() {
+
+      @Override
+      public String ifUnmodifiedSince() {
+        return null;
+      }
+
+      @Override
+      public void handleRequestSuccess(SyncStorageResponse response) {
+        Logger.debug(LOG_TAG, "Keys uploaded.");
+        BaseResource.consumeEntity(response); // We don't need the response at all.
+        keyUploadDelegate.onKeysUploaded();
+      }
+
+      @Override
+      public void handleRequestFailure(SyncStorageResponse response) {
+        Logger.debug(LOG_TAG, "Failed to upload keys.");
+        GlobalSession.this.interpretHTTPFailure(response.httpResponse());
+        BaseResource.consumeEntity(response); // The exception thrown should not need the body of the response.
+        keyUploadDelegate.onKeyUploadFailed(new HTTPFailureException(response));
+      }
+
+      @Override
+      public void handleRequestError(Exception ex) {
+        Logger.warn(LOG_TAG, "Got exception trying to upload keys", ex);
+        keyUploadDelegate.onKeyUploadFailed(ex);
+      }
+
+      @Override
+      public AuthHeaderProvider getAuthHeaderProvider() {
+        return GlobalSession.this.getAuthHeaderProvider();
+      }
+    };
+
+    // Convert keys to an encrypted crypto record.
+    CryptoRecord keysRecord;
+    try {
+      keysRecord = keys.asCryptoRecord();
+      keysRecord.setKeyBundle(config.syncKeyBundle);
+      keysRecord.encrypt();
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception trying creating crypto record from keys", e);
+      keyUploadDelegate.onKeyUploadFailed(e);
+      return;
+    }
+
+    request.put(keysRecord);
+  }
+
+  /*
+   * meta/global callbacks.
+   */
+  public void processMetaGlobal(MetaGlobal global) {
+    config.metaGlobal = global;
+
+    Long storageVersion = global.getStorageVersion();
+    if (storageVersion == null) {
+      Logger.warn(LOG_TAG, "Malformed remote meta/global: could not retrieve remote storage version.");
+      freshStart();
+      return;
+    }
+    if (storageVersion < STORAGE_VERSION) {
+      Logger.warn(LOG_TAG, "Outdated server: reported " +
+          "remote storage version " + storageVersion + " < " +
+          "local storage version " + STORAGE_VERSION);
+      freshStart();
+      return;
+    }
+    if (storageVersion > STORAGE_VERSION) {
+      Logger.warn(LOG_TAG, "Outdated client: reported " +
+          "remote storage version " + storageVersion + " > " +
+          "local storage version " + STORAGE_VERSION);
+      requiresUpgrade();
+      return;
+    }
+    String remoteSyncID = global.getSyncID();
+    if (remoteSyncID == null) {
+      Logger.warn(LOG_TAG, "Malformed remote meta/global: could not retrieve remote syncID.");
+      freshStart();
+      return;
+    }
+    String localSyncID = config.syncID;
+    if (!remoteSyncID.equals(localSyncID)) {
+      Logger.warn(LOG_TAG, "Remote syncID different from local syncID: resetting client and assuming remote syncID.");
+      resetAllStages();
+      config.purgeCryptoKeys();
+      config.syncID = remoteSyncID;
+    }
+    // Compare lastModified timestamps for remote/local engine selection times.
+    Logger.debug(LOG_TAG, "Comparing local engine selection timestamp [" + config.userSelectedEnginesTimestamp + "] to server meta/global timestamp [" + config.persistedMetaGlobal().lastModified() + "].");
+    if (config.userSelectedEnginesTimestamp < config.persistedMetaGlobal().lastModified()) {
+      // Remote has later meta/global timestamp. Don't upload engine changes.
+      config.userSelectedEngines = null;
+    }
+    // Persist enabled engine names.
+    config.enabledEngineNames = global.getEnabledEngineNames();
+    if (config.enabledEngineNames == null) {
+      Logger.warn(LOG_TAG, "meta/global reported no enabled engine names!");
+    } else {
+      if (Logger.shouldLogVerbose(LOG_TAG)) {
+        Logger.trace(LOG_TAG, "Persisting enabled engine names '" +
+            Utils.toCommaSeparatedString(config.enabledEngineNames) + "' from meta/global.");
+      }
+    }
+
+    // Persist declined.
+    // Our declined engines at any point are:
+    // Whatever they were remotely, plus whatever they were locally, less any
+    // engines that were just enabled locally or remotely.
+    // If remote just 'won', our recently enabled list just got cleared.
+    final HashSet<String> allDeclined = new HashSet<String>();
+
+    final Set<String> newRemoteDeclined = global.getDeclinedEngineNames();
+    final Set<String> oldLocalDeclined = config.declinedEngineNames;
+
+    allDeclined.addAll(newRemoteDeclined);
+    allDeclined.addAll(oldLocalDeclined);
+
+    if (config.userSelectedEngines != null) {
+      for (Entry<String, Boolean> selection : config.userSelectedEngines.entrySet()) {
+        if (selection.getValue()) {
+          allDeclined.remove(selection.getKey());
+        }
+      }
+    }
+
+    config.declinedEngineNames = allDeclined;
+    if (config.declinedEngineNames.isEmpty()) {
+      Logger.debug(LOG_TAG, "meta/global reported no declined engine names, and we have none declined locally.");
+    } else {
+      if (Logger.shouldLogVerbose(LOG_TAG)) {
+        Logger.trace(LOG_TAG, "Persisting declined engine names '" +
+            Utils.toCommaSeparatedString(config.declinedEngineNames) + "' from meta/global.");
+      }
+    }
+
+    config.persistToPrefs();
+    advance();
+  }
+
+  public void processMissingMetaGlobal(MetaGlobal global) {
+    freshStart();
+  }
+
+  /**
+   * Do a fresh start then quietly finish the sync, starting another.
+   */
+  public void freshStart() {
+    final GlobalSession globalSession = this;
+    freshStart(this, new FreshStartDelegate() {
+
+      @Override
+      public void onFreshStartFailed(Exception e) {
+        globalSession.abort(e, "Fresh start failed.");
+      }
+
+      @Override
+      public void onFreshStart() {
+        try {
+          Logger.warn(LOG_TAG, "Fresh start succeeded; restarting global session.");
+          globalSession.config.persistToPrefs();
+          globalSession.restart();
+        } catch (Exception e) {
+          Logger.warn(LOG_TAG, "Got exception when restarting sync after freshStart.", e);
+          globalSession.abort(e, "Got exception after freshStart.");
+        }
+      }
+    });
+  }
+
+  /**
+   * Clean the server, aborting the current sync.
+   * <p>
+   * <ol>
+   * <li>Wipe the server storage.</li>
+   * <li>Reset all stages and purge cached state: (meta/global and crypto/keys records).</li>
+   * <li>Upload fresh meta/global record.</li>
+   * <li>Upload fresh crypto/keys record.</li>
+   * <li>Restart the sync entirely in order to re-download meta/global and crypto/keys record.</li>
+   * </ol>
+   * @param session the current session.
+   * @param freshStartDelegate delegate to notify on fresh start or failure.
+   */
+  protected static void freshStart(final GlobalSession session, final FreshStartDelegate freshStartDelegate) {
+    Logger.debug(LOG_TAG, "Fresh starting.");
+
+    final MetaGlobal mg = session.generateNewMetaGlobal();
+
+    session.wipeServer(session.getAuthHeaderProvider(), new WipeServerDelegate() {
+
+      @Override
+      public void onWiped(long timestamp) {
+        Logger.debug(LOG_TAG, "Successfully wiped server.  Resetting all stages and purging cached meta/global and crypto/keys records.");
+
+        session.resetAllStages();
+        session.config.purgeMetaGlobal();
+        session.config.purgeCryptoKeys();
+        session.config.persistToPrefs();
+
+        Logger.info(LOG_TAG, "Uploading new meta/global with sync ID " + mg.syncID + ".");
+
+        // It would be good to set the X-If-Unmodified-Since header to `timestamp`
+        // for this PUT to ensure at least some level of transactionality.
+        // Unfortunately, the servers don't support it after a wipe right now
+        // (bug 693893), so we're going to defer this until bug 692700.
+        mg.upload(new MetaGlobalDelegate() {
+          @Override
+          public void handleSuccess(MetaGlobal uploadedGlobal, SyncStorageResponse uploadResponse) {
+            Logger.info(LOG_TAG, "Uploaded new meta/global with sync ID " + uploadedGlobal.syncID + ".");
+
+            // Generate new keys.
+            CollectionKeys keys = null;
+            try {
+              keys = session.generateNewCryptoKeys();
+            } catch (CryptoException e) {
+              Logger.warn(LOG_TAG, "Got exception generating new keys; failing fresh start.", e);
+              freshStartDelegate.onFreshStartFailed(e);
+            }
+            if (keys == null) {
+              Logger.warn(LOG_TAG, "Got null keys from generateNewKeys; failing fresh start.");
+              freshStartDelegate.onFreshStartFailed(null);
+            }
+
+            // Upload new keys.
+            Logger.info(LOG_TAG, "Uploading new crypto/keys.");
+            session.uploadKeys(keys, new KeyUploadDelegate() {
+              @Override
+              public void onKeysUploaded() {
+                Logger.info(LOG_TAG, "Uploaded new crypto/keys.");
+                freshStartDelegate.onFreshStart();
+              }
+
+              @Override
+              public void onKeyUploadFailed(Exception e) {
+                Logger.warn(LOG_TAG, "Got exception uploading new keys.", e);
+                freshStartDelegate.onFreshStartFailed(e);
+              }
+            });
+          }
+
+          @Override
+          public void handleMissing(MetaGlobal global, SyncStorageResponse response) {
+            // Shouldn't happen on upload.
+            Logger.warn(LOG_TAG, "Got 'missing' response uploading new meta/global.");
+            freshStartDelegate.onFreshStartFailed(new Exception("meta/global missing while uploading."));
+          }
+
+          @Override
+          public void handleFailure(SyncStorageResponse response) {
+            Logger.warn(LOG_TAG, "Got failure " + response.getStatusCode() + " uploading new meta/global.");
+            session.interpretHTTPFailure(response.httpResponse());
+            freshStartDelegate.onFreshStartFailed(new HTTPFailureException(response));
+          }
+
+          @Override
+          public void handleError(Exception e) {
+            Logger.warn(LOG_TAG, "Got error uploading new meta/global.", e);
+            freshStartDelegate.onFreshStartFailed(e);
+          }
+        });
+      }
+
+      @Override
+      public void onWipeFailed(Exception e) {
+        Logger.warn(LOG_TAG, "Wipe failed.");
+        freshStartDelegate.onFreshStartFailed(e);
+      }
+    });
+  }
+
+  // Note that we do not yet implement wipeRemote: it's only necessary for
+  // first sync options.
+  // -- reset local stages, wipe server for each stage *except* clients
+  //    (stages only, not whole server!), send wipeEngine commands to each client.
+  //
+  // Similarly for startOver (because we don't receive that notification).
+  // -- remove client data from server, reset local stages, clear keys, reset
+  //    backoff, clear all prefs, discard credentials.
+  //
+  // Change passphrase: wipe entire server, reset client to force upload, sync.
+  //
+  // When an engine is disabled: wipe its collections on the server, reupload
+  // meta/global.
+  //
+  // On syncing each stage: if server has engine version 0 or old, wipe server,
+  // reset client to prompt reupload.
+  // If sync ID mismatch: take that syncID and reset client.
+
+  protected void wipeServer(final AuthHeaderProvider authHeaderProvider, final WipeServerDelegate wipeDelegate) {
+    SyncStorageRequest request;
+    final GlobalSession self = this;
+
+    try {
+      request = new SyncStorageRequest(config.storageURL());
+    } catch (URISyntaxException ex) {
+      Logger.warn(LOG_TAG, "Invalid URI in wipeServer.");
+      wipeDelegate.onWipeFailed(ex);
+      return;
+    }
+
+    request.delegate = new SyncStorageRequestDelegate() {
+
+      @Override
+      public String ifUnmodifiedSince() {
+        return null;
+      }
+
+      @Override
+      public void handleRequestSuccess(SyncStorageResponse response) {
+        BaseResource.consumeEntity(response);
+        wipeDelegate.onWiped(response.normalizedWeaveTimestamp());
+      }
+
+      @Override
+      public void handleRequestFailure(SyncStorageResponse response) {
+        Logger.warn(LOG_TAG, "Got request failure " + response.getStatusCode() + " in wipeServer.");
+        // Process HTTP failures here to pick up backoffs, etc.
+        self.interpretHTTPFailure(response.httpResponse());
+        BaseResource.consumeEntity(response); // The exception thrown should not need the body of the response.
+        wipeDelegate.onWipeFailed(new HTTPFailureException(response));
+      }
+
+      @Override
+      public void handleRequestError(Exception ex) {
+        Logger.warn(LOG_TAG, "Got exception in wipeServer.", ex);
+        wipeDelegate.onWipeFailed(ex);
+      }
+
+      @Override
+      public AuthHeaderProvider getAuthHeaderProvider() {
+        return GlobalSession.this.getAuthHeaderProvider();
+      }
+    };
+    request.delete();
+  }
+
+  public void wipeAllStages() {
+    Logger.info(LOG_TAG, "Wiping all stages.");
+    // Includes "clients".
+    this.wipeStagesByEnum(Stage.getNamedStages());
+  }
+
+  public void wipeStages(Collection<GlobalSyncStage> stages) {
+    for (GlobalSyncStage stage : stages) {
+      try {
+        Logger.info(LOG_TAG, "Wiping " + stage);
+        stage.wipeLocal(this);
+      } catch (Exception e) {
+        Logger.error(LOG_TAG, "Ignoring wipe failure for stage " + stage, e);
+      }
+    }
+  }
+
+  public void wipeStagesByEnum(Collection<Stage> stages) {
+    wipeStages(this.getSyncStagesByEnum(stages));
+  }
+
+  public void wipeStagesByName(Collection<String> names) {
+    wipeStages(this.getSyncStagesByName(names));
+  }
+
+  public void resetAllStages() {
+    Logger.info(LOG_TAG, "Resetting all stages.");
+    // Includes "clients".
+    this.resetStagesByEnum(Stage.getNamedStages());
+  }
+
+  public void resetStages(Collection<GlobalSyncStage> stages) {
+    for (GlobalSyncStage stage : stages) {
+      try {
+        Logger.info(LOG_TAG, "Resetting " + stage);
+        stage.resetLocal(this);
+      } catch (Exception e) {
+        Logger.error(LOG_TAG, "Ignoring reset failure for stage " + stage, e);
+      }
+    }
+  }
+
+  public void resetStagesByEnum(Collection<Stage> stages) {
+    resetStages(this.getSyncStagesByEnum(stages));
+  }
+
+  public void resetStagesByName(Collection<String> names) {
+    resetStages(this.getSyncStagesByName(names));
+  }
+
+  /**
+   * Engines to explicitly mark as declined in a fresh meta/global record.
+   * <p>
+   * Returns an empty array if the user hasn't elected to customize data types,
+   * or an array of engines that the user un-checked during customization.
+   * <p>
+   * Engines that Android Sync doesn't recognize are <b>not</b> included in
+   * the returned array.
+   *
+   * @return a new JSONArray of engine names.
+   */
+  @SuppressWarnings("unchecked")
+  protected JSONArray declinedEngineNames() {
+    final JSONArray declined = new JSONArray();
+    for (String engine : config.declinedEngineNames) {
+      declined.add(engine);
+    };
+
+    return declined;
+  }
+
+  /**
+   * Engines to include in a fresh meta/global record.
+   * <p>
+   * Returns either the persisted engine names (perhaps we have been node
+   * re-assigned and are initializing a clean server: we want to upload the
+   * persisted engine names so that we don't accidentally disable engines that
+   * Android Sync doesn't recognize), or the set of engines names that Android
+   * Sync implements.
+   *
+   * @return set of engine names.
+   */
+  protected Set<String> enabledEngineNames() {
+    if (config.enabledEngineNames != null) {
+      return config.enabledEngineNames;
+    }
+
+    // These are the default set of engine names.
+    Set<String> validEngineNames = SyncConfiguration.validEngineNames();
+
+    // If the user hasn't set any selected engines, that's okay -- default to
+    // everything.
+    if (config.userSelectedEngines == null) {
+      return validEngineNames;
+    }
+
+    // userSelectedEngines has keys that are engine names, and boolean values
+    // corresponding to whether the user asked for the engine to sync or not. If
+    // an engine is not present, that means the user didn't change its sync
+    // setting. Since we default to everything on, that means the user didn't
+    // turn it off; therefore, it's included in the set of engines to sync.
+    Set<String> validAndSelectedEngineNames = new HashSet<String>();
+    for (String engineName : validEngineNames) {
+      if (config.userSelectedEngines.containsKey(engineName) &&
+          !config.userSelectedEngines.get(engineName)) {
+        continue;
+      }
+      validAndSelectedEngineNames.add(engineName);
+    }
+    return validAndSelectedEngineNames;
+  }
+
+  /**
+   * Generate fresh crypto/keys collection.
+   * @return crypto/keys collection.
+   * @throws CryptoException
+   */
+  @SuppressWarnings("static-method")
+  public CollectionKeys generateNewCryptoKeys() throws CryptoException {
+    return CollectionKeys.generateCollectionKeys();
+  }
+
+  /**
+   * Generate a fresh meta/global record.
+   * @return meta/global record.
+   */
+  public MetaGlobal generateNewMetaGlobal() {
+    final String newSyncID   = Utils.generateGuid();
+    final String metaURL     = this.config.metaURL();
+
+    ExtendedJSONObject engines = new ExtendedJSONObject();
+    for (String engineName : enabledEngineNames()) {
+      EngineSettings engineSettings = null;
+      try {
+        GlobalSyncStage globalStage = this.getSyncStageByName(engineName);
+        Integer version = globalStage.getStorageVersion();
+        if (version == null) {
+          continue; // Don't want this stage to be included in meta/global.
+        }
+        engineSettings = new EngineSettings(Utils.generateGuid(), version);
+      } catch (NoSuchStageException e) {
+        // No trouble; Android Sync might not recognize this engine yet.
+        // By default, version 0.  Other clients will see the 0 version and reset/wipe accordingly.
+        engineSettings = new EngineSettings(Utils.generateGuid(), 0);
+      }
+      engines.put(engineName, engineSettings.toJSONObject());
+    }
+
+    MetaGlobal metaGlobal = new MetaGlobal(metaURL, this.getAuthHeaderProvider());
+    metaGlobal.setSyncID(newSyncID);
+    metaGlobal.setStorageVersion(STORAGE_VERSION);
+    metaGlobal.setEngines(engines);
+
+    // We assume that the config's declined engines have been updated
+    // according to the user's selections.
+    metaGlobal.setDeclinedEngineNames(this.declinedEngineNames());
+
+    return metaGlobal;
+  }
+
+  /**
+   * Suggest that your Sync client needs to be upgraded to work
+   * with this server.
+   */
+  public void requiresUpgrade() {
+    Logger.info(LOG_TAG, "Client outdated storage version; requires update.");
+    // TODO: notify UI.
+    this.abort(null, "Requires upgrade");
+  }
+
+  /**
+   * If meta/global is missing or malformed, throws a MetaGlobalException.
+   * Otherwise, returns true if there is an entry for this engine in the
+   * meta/global "engines" object.
+   * <p>
+   * This is a global/permanent setting, not a local/temporary setting. For the
+   * latter, see {@link GlobalSession#isEngineLocallyEnabled(String)}.
+   *
+   * @param engineName the name to check (e.g., "bookmarks").
+   * @param engineSettings
+   *        if non-null, verify that the server engine settings are congruent
+   *        with this, throwing the appropriate MetaGlobalException if not.
+   * @return
+   *        true if the engine with the provided name is present in the
+   *        meta/global "engines" object, and verification passed.
+   *
+   * @throws MetaGlobalException
+   */
+  public boolean isEngineRemotelyEnabled(String engineName, EngineSettings engineSettings) throws MetaGlobalException {
+    if (this.config.metaGlobal == null) {
+      throw new MetaGlobalNotSetException();
+    }
+
+    // This should not occur.
+    if (this.config.enabledEngineNames == null) {
+      Logger.error(LOG_TAG, "No enabled engines in config. Giving up.");
+      throw new MetaGlobalMissingEnginesException();
+    }
+
+    if (!(this.config.enabledEngineNames.contains(engineName))) {
+      Logger.debug(LOG_TAG, "Engine " + engineName + " not enabled: no meta/global entry.");
+      return false;
+    }
+
+    // If we have a meta/global, check that it's safe for us to sync.
+    // (If we don't, we'll create one later, which is why we return `true` above.)
+    if (engineSettings != null) {
+      // Throws if there's a problem.
+      this.config.metaGlobal.verifyEngineSettings(engineName, engineSettings);
+    }
+
+    return true;
+  }
+
+
+  /**
+   * Return true if the named stage should be synced this session.
+   * <p>
+   * This is a local/temporary setting, in contrast to the meta/global record,
+   * which is a global/permanent setting. For the latter, see
+   * {@link GlobalSession#isEngineRemotelyEnabled(String, EngineSettings)}.
+   *
+   * @param stageName
+   *          to query.
+   * @return true if named stage is enabled for this sync.
+   */
+  public boolean isEngineLocallyEnabled(String stageName) {
+    if (config.stagesToSync == null) {
+      return true;
+    }
+    return config.stagesToSync.contains(stageName);
+  }
+
+  public ClientsDataDelegate getClientsDelegate() {
+    return this.clientsDelegate;
+  }
+
+  /**
+   * The longest backoff observed to date; -1 means no backoff observed.
+   */
+  protected final AtomicLong largestBackoffObserved = new AtomicLong(-1);
+
+  /**
+   * Reset any observed backoff and start observing HTTP responses for backoff
+   * requests.
+   */
+  protected void installAsHttpResponseObserver() {
+    Logger.debug(LOG_TAG, "Adding " + this + " as a BaseResource HttpResponseObserver.");
+    BaseResource.addHttpResponseObserver(this);
+    largestBackoffObserved.set(-1);
+  }
+
+  /**
+   * Stop observing HttpResponses for backoff requests.
+   */
+  protected void uninstallAsHttpResponseObserver() {
+    Logger.debug(LOG_TAG, "Removing " + this + " as a BaseResource HttpResponseObserver.");
+    BaseResource.removeHttpResponseObserver(this);
+  }
+
+  /**
+   * Observe all HTTP response for backoff requests on all status codes, not just errors.
+   */
+  @Override
+  public void observeHttpResponse(HttpUriRequest request, HttpResponse response) {
+    // Ignore non-Sync storage requests.
+    final URI clusterURL = config.getClusterURL();
+    if (clusterURL != null && !clusterURL.getHost().equals(request.getURI().getHost())) {
+      // It's possible to see requests without a clusterURL (in particular,
+      // during testing); allow some extra backoffs in this case.
+      return;
+    }
+
+    long responseBackoff = (new SyncResponse(response)).totalBackoffInMilliseconds(); // TODO: don't allocate object?
+    if (responseBackoff <= 0) {
+      return;
+    }
+
+    Logger.debug(LOG_TAG, "Observed " + responseBackoff + " millisecond backoff request.");
+    while (true) {
+      long existingBackoff = largestBackoffObserved.get();
+      if (existingBackoff >= responseBackoff) {
+        return;
+      }
+      if (largestBackoffObserved.compareAndSet(existingBackoff, responseBackoff)) {
+        return;
+      }
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/HTTPFailureException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/HTTPFailureException.java
new file mode 100644
index 000000000..69bba8841
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/HTTPFailureException.java
@@ -0,0 +1,47 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+import android.content.SyncResult;
+
+public class HTTPFailureException extends SyncException {
+  private static final long serialVersionUID = -5415864029780770619L;
+  public SyncStorageResponse response;
+
+  public HTTPFailureException(SyncStorageResponse response) {
+    this.response = response;
+  }
+
+  @Override
+  public String toString() {
+    String errorMessage;
+    try {
+      errorMessage = this.response.getErrorMessage();
+    } catch (Exception e) {
+      // Oh well.
+      errorMessage = "[unknown error message]";
+    }
+    return "<HTTPFailureException " + this.response.getStatusCode() +
+           " :: (" + errorMessage + ")>";
+  }
+
+  @Override
+  public void updateStats(GlobalSession globalSession, SyncResult syncResult) {
+    switch (response.getStatusCode()) {
+    case 401:
+      // Node reassignment 401s get handled internally.
+      syncResult.stats.numAuthExceptions++;
+      return;
+    case 500:
+    case 501:
+    case 503:
+      // TODO: backoff.
+      syncResult.stats.numIoExceptions++;
+      return;
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/InfoCollections.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/InfoCollections.java
new file mode 100644
index 000000000..374fa5cf5
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/InfoCollections.java
@@ -0,0 +1,103 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+/**
+ * Fetches the timestamp information in <code>info/collections</code> on the
+ * Sync server. Provides access to those timestamps, along with logic to check
+ * for whether a collection requires an update.
+ */
+public class InfoCollections {
+  private static final String LOG_TAG = "InfoCollections";
+
+  /**
+   * Fields fetched from the server, or <code>null</code> if not yet fetched.
+   * <p>
+   * Rather than storing decimal/double timestamps, as provided by the server,
+   * we convert immediately to milliseconds since epoch.
+   */
+  final Map<String, Long> timestamps;
+
+  public InfoCollections() {
+    this(new ExtendedJSONObject());
+  }
+
+  public InfoCollections(final ExtendedJSONObject record) {
+    Logger.debug(LOG_TAG, "info/collections is " + record.toJSONString());
+    HashMap<String, Long> map = new HashMap<String, Long>();
+
+    for (Entry<String, Object> entry : record.entrySet()) {
+      final String key = entry.getKey();
+      final Object value = entry.getValue();
+
+      // These objects are most likely going to be Doubles. Regardless, we
+      // want to get them in a more sane time format.
+      if (value instanceof Double) {
+        map.put(key, Utils.decimalSecondsToMilliseconds((Double) value));
+        continue;
+      }
+      if (value instanceof Long) {
+        map.put(key, Utils.decimalSecondsToMilliseconds((Long) value));
+        continue;
+      }
+      if (value instanceof Integer) {
+        map.put(key, Utils.decimalSecondsToMilliseconds((Integer) value));
+        continue;
+      }
+      Logger.warn(LOG_TAG, "Skipping info/collections entry for " + key);
+    }
+
+    this.timestamps = Collections.unmodifiableMap(map);
+  }
+
+  /**
+   * Return the timestamp for the given collection, or null if the timestamps
+   * have not been fetched or the given collection does not have a timestamp.
+   *
+   * @param collection
+   *          The collection to inspect.
+   * @return the timestamp in milliseconds since epoch.
+   */
+  public Long getTimestamp(String collection) {
+    if (timestamps == null) {
+      return null;
+    }
+    return timestamps.get(collection);
+  }
+
+  /**
+   * Test if a given collection needs to be updated.
+   *
+   * @param collection
+   *          The collection to test.
+   * @param lastModified
+   *          Timestamp when local record was last modified.
+   */
+  public boolean updateNeeded(String collection, long lastModified) {
+    Logger.trace(LOG_TAG, "Testing " + collection + " for updateNeeded. Local last modified is " + lastModified + ".");
+
+    // No local record of modification time? Need an update.
+    if (lastModified <= 0) {
+      return true;
+    }
+
+    // No meta/global on the server? We need an update. The server fetch will fail and
+    // then we will upload a fresh meta/global.
+    Long serverLastModified = getTimestamp(collection);
+    if (serverLastModified == null) {
+      return true;
+    }
+
+    // Otherwise, we need an update if our modification time is stale.
+    return serverLastModified > lastModified;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/InfoConfiguration.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/InfoConfiguration.java
new file mode 100644
index 000000000..eb2428433
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/InfoConfiguration.java
@@ -0,0 +1,93 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.util.Log;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+/**
+ * Wraps and provides access to configuration data returned from info/configuration.
+ * Docs: https://docs.services.mozilla.com/storage/apis-1.5.html#general-info
+ *
+ * - <bold>max_request_bytes</bold>: the maximum size in bytes of the overall
+ *   HTTP request body that will be accepted by the server.
+ *
+ * - <bold>max_post_records</bold>: the maximum number of records that can be
+ *   uploaded to a collection in a single POST request.
+ *
+ * - <bold>max_post_bytes</bold>: the maximum combined size in bytes of the
+ *   record payloads that can be uploaded to a collection in a single
+ *   POST request.
+ *
+ * - <bold>max_total_records</bold>: the maximum number of records that can be
+ *   uploaded to a collection as part of a batched upload.
+ *
+ * - <bold>max_total_bytes</bold>: the maximum combined size in bytes of the
+ *   record payloads that can be uploaded to a collection as part of
+ *   a batched upload.
+ */
+public class InfoConfiguration {
+    private static final String LOG_TAG = "InfoConfiguration";
+
+    public static final String MAX_REQUEST_BYTES = "max_request_bytes";
+    public static final String MAX_POST_RECORDS = "max_post_records";
+    public static final String MAX_POST_BYTES = "max_post_bytes";
+    public static final String MAX_TOTAL_RECORDS = "max_total_records";
+    public static final String MAX_TOTAL_BYTES = "max_total_bytes";
+
+    private static final long DEFAULT_MAX_REQUEST_BYTES = 1048576;
+    private static final long DEFAULT_MAX_POST_RECORDS = 100;
+    private static final long DEFAULT_MAX_POST_BYTES = 1048576;
+    private static final long DEFAULT_MAX_TOTAL_RECORDS = 10000;
+    private static final long DEFAULT_MAX_TOTAL_BYTES = 104857600;
+
+    // While int's upper range is (2^31-1), which in bytes is equivalent to 2.147 GB, let's be optimistic
+    // about the future and use long here, so that this code works if the server decides its clients are
+    // all on fiber and have congress-library sized bookmark collections.
+    // Record counts are long for the sake of simplicity.
+    public final long maxRequestBytes;
+    public final long maxPostRecords;
+    public final long maxPostBytes;
+    public final long maxTotalRecords;
+    public final long maxTotalBytes;
+
+    public InfoConfiguration() {
+        Logger.debug(LOG_TAG, "info/configuration is unavailable, using defaults");
+
+        maxRequestBytes = DEFAULT_MAX_REQUEST_BYTES;
+        maxPostRecords = DEFAULT_MAX_POST_RECORDS;
+        maxPostBytes = DEFAULT_MAX_POST_BYTES;
+        maxTotalRecords = DEFAULT_MAX_TOTAL_RECORDS;
+        maxTotalBytes = DEFAULT_MAX_TOTAL_BYTES;
+    }
+
+    public InfoConfiguration(final ExtendedJSONObject record) {
+        Logger.debug(LOG_TAG, "info/configuration is " + record.toJSONString());
+
+        maxRequestBytes = getValueFromRecord(record, MAX_REQUEST_BYTES, DEFAULT_MAX_REQUEST_BYTES);
+        maxPostRecords = getValueFromRecord(record, MAX_POST_RECORDS, DEFAULT_MAX_POST_RECORDS);
+        maxPostBytes = getValueFromRecord(record, MAX_POST_BYTES, DEFAULT_MAX_POST_BYTES);
+        maxTotalRecords = getValueFromRecord(record, MAX_TOTAL_RECORDS, DEFAULT_MAX_TOTAL_RECORDS);
+        maxTotalBytes = getValueFromRecord(record, MAX_TOTAL_BYTES, DEFAULT_MAX_TOTAL_BYTES);
+    }
+
+    private static Long getValueFromRecord(ExtendedJSONObject record, String key, long defaultValue) {
+        if (!record.containsKey(key)) {
+            return defaultValue;
+        }
+
+        try {
+            Long val = record.getLong(key);
+            if (val == null) {
+                return defaultValue;
+            }
+            return val;
+        } catch (NumberFormatException e) {
+            Log.w(LOG_TAG, "Could not parse key " + key + " from record: " + record, e);
+            return defaultValue;
+        }
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/InfoCounts.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/InfoCounts.java
new file mode 100644
index 000000000..832e97d10
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/InfoCounts.java
@@ -0,0 +1,67 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+public class InfoCounts {
+  static final String LOG_TAG = "InfoCounts";
+
+  /**
+   * Counts fetched from the server, or <code>null</code> if not yet fetched.
+   */
+  private Map<String, Integer> counts = null;
+
+  @SuppressWarnings("unchecked")
+  public InfoCounts(final ExtendedJSONObject record) {
+    Logger.debug(LOG_TAG, "info/collection_counts is " + record.toJSONString());
+    HashMap<String, Integer> map = new HashMap<String, Integer>();
+
+    Set<Entry<String, Object>> entrySet = record.object.entrySet();
+
+    String key;
+    Object value;
+
+    for (Entry<String, Object> entry : entrySet) {
+      key = entry.getKey();
+      value = entry.getValue();
+
+      if (value instanceof Integer) {
+        map.put(key, (Integer) value);
+        continue;
+      }
+
+      if (value instanceof Long) {
+        map.put(key, ((Long) value).intValue());
+        continue;
+      }
+
+      Logger.warn(LOG_TAG, "Skipping info/collection_counts entry for " + key);
+    }
+
+    this.counts = Collections.unmodifiableMap(map);
+  }
+
+  /**
+   * Return the server count for the given collection, or null if the counts
+   * have not been fetched or the given collection does not have a count.
+   *
+   * @param collection
+   *          The collection to inspect.
+   * @return the number of elements in the named collection.
+   */
+  public Integer getCount(String collection) {
+    if (counts == null) {
+      return null;
+    }
+    return counts.get(collection);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/JSONRecordFetcher.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/JSONRecordFetcher.java
new file mode 100644
index 000000000..982b5b026
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/JSONRecordFetcher.java
@@ -0,0 +1,145 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.delegates.JSONRecordFetchDelegate;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.SyncStorageRecordRequest;
+import org.mozilla.gecko.sync.net.SyncStorageRequestDelegate;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+/**
+ * An object which fetches a chunk of JSON from a URI, using certain credentials,
+ * and informs its delegate of the result.
+ */
+public class JSONRecordFetcher {
+  private static final long DEFAULT_AWAIT_TIMEOUT_MSEC = 2 * 60 * 1000;   // Two minutes.
+  private static final String LOG_TAG = "JSONRecordFetcher";
+
+  protected final AuthHeaderProvider authHeaderProvider;
+  protected final String uri;
+  protected JSONRecordFetchDelegate delegate;
+
+  public JSONRecordFetcher(final String uri, final AuthHeaderProvider authHeaderProvider) {
+    if (uri == null) {
+      throw new IllegalArgumentException("uri must not be null");
+    }
+    this.uri = uri;
+    this.authHeaderProvider = authHeaderProvider;
+  }
+
+  protected String getURI() {
+    return this.uri;
+  }
+
+  private class JSONFetchHandler implements SyncStorageRequestDelegate {
+
+    // SyncStorageRequestDelegate methods for fetching.
+    @Override
+    public AuthHeaderProvider getAuthHeaderProvider() {
+      return authHeaderProvider;
+    }
+
+    @Override
+    public String ifUnmodifiedSince() {
+      return null;
+    }
+
+    @Override
+    public void handleRequestSuccess(SyncStorageResponse response) {
+      if (response.wasSuccessful()) {
+        try {
+          delegate.handleSuccess(response.jsonObjectBody());
+        } catch (Exception e) {
+          handleRequestError(e);
+        }
+        return;
+      }
+      handleRequestFailure(response);
+    }
+
+    @Override
+    public void handleRequestFailure(SyncStorageResponse response) {
+      delegate.handleFailure(response);
+    }
+
+    @Override
+    public void handleRequestError(Exception ex) {
+      delegate.handleError(ex);
+    }
+  }
+
+  public void fetch(final JSONRecordFetchDelegate delegate) {
+    this.delegate = delegate;
+    try {
+      final SyncStorageRecordRequest r = new SyncStorageRecordRequest(this.getURI());
+      r.delegate = new JSONFetchHandler();
+      r.get();
+    } catch (Exception e) {
+      delegate.handleError(e);
+    }
+  }
+
+  private class LatchedJSONRecordFetchDelegate implements JSONRecordFetchDelegate {
+    public ExtendedJSONObject body = null;
+    public Exception exception = null;
+    private final CountDownLatch latch;
+
+    public LatchedJSONRecordFetchDelegate(CountDownLatch latch) {
+      this.latch = latch;
+    }
+
+    @Override
+    public void handleFailure(SyncStorageResponse response) {
+      this.exception = new HTTPFailureException(response);
+      latch.countDown();
+    }
+
+    @Override
+    public void handleError(Exception e) {
+      this.exception = e;
+      latch.countDown();
+    }
+
+    @Override
+    public void handleSuccess(ExtendedJSONObject body) {
+      this.body = body;
+      latch.countDown();
+    }
+  }
+
+  /**
+   * Fetch the info record, blocking until it returns.
+   * @return the info record.
+   */
+  public ExtendedJSONObject fetchBlocking() throws HTTPFailureException, Exception {
+    CountDownLatch latch = new CountDownLatch(1);
+    LatchedJSONRecordFetchDelegate delegate = new LatchedJSONRecordFetchDelegate(latch);
+    this.delegate = delegate;
+    this.fetch(delegate);
+
+    // Sanity wait: the resource itself will time out and throw after two
+    // minutes, so we just want to avoid coding errors causing us to block
+    // endlessly.
+    if (!latch.await(DEFAULT_AWAIT_TIMEOUT_MSEC, TimeUnit.MILLISECONDS)) {
+      Logger.warn(LOG_TAG, "Interrupted fetching info record.");
+      throw new InterruptedException("info fetch timed out.");
+    }
+
+    if (delegate.body != null) {
+      return delegate.body;
+    }
+
+    if (delegate.exception != null) {
+      throw delegate.exception;
+    }
+
+    throw new Exception("Unknown error.");
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/KeyBundleProvider.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/KeyBundleProvider.java
new file mode 100644
index 000000000..4a2be2a9b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/KeyBundleProvider.java
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+
+public interface KeyBundleProvider {
+  public abstract KeyBundle keyBundle();
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobal.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobal.java
new file mode 100644
index 000000000..a90c0fee8
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobal.java
@@ -0,0 +1,372 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.json.simple.JSONArray;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.MetaGlobalException.MetaGlobalMalformedSyncIDException;
+import org.mozilla.gecko.sync.MetaGlobalException.MetaGlobalMalformedVersionException;
+import org.mozilla.gecko.sync.delegates.MetaGlobalDelegate;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.SyncStorageRecordRequest;
+import org.mozilla.gecko.sync.net.SyncStorageRequestDelegate;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+public class MetaGlobal implements SyncStorageRequestDelegate {
+  private static final String LOG_TAG = "MetaGlobal";
+  protected String metaURL;
+
+  // Fields.
+  protected ExtendedJSONObject  engines;
+  protected JSONArray           declined;
+  protected Long                storageVersion;
+  protected String              syncID;
+
+  // Lookup tables.
+  protected Map<String, String> syncIDs;
+  protected Map<String, Integer> versions;
+  protected Map<String, MetaGlobalException> exceptions;
+
+  // Temporary location to store our callback.
+  private MetaGlobalDelegate callback;
+
+  // A little hack so we can use the same delegate implementation for upload and download.
+  private boolean isUploading;
+  protected final AuthHeaderProvider authHeaderProvider;
+
+  public MetaGlobal(String metaURL, AuthHeaderProvider authHeaderProvider) {
+    this.metaURL = metaURL;
+    this.authHeaderProvider = authHeaderProvider;
+  }
+
+  public void fetch(MetaGlobalDelegate delegate) {
+    this.callback = delegate;
+    try {
+      this.isUploading = false;
+      SyncStorageRecordRequest r = new SyncStorageRecordRequest(this.metaURL);
+      r.delegate = this;
+      r.get();
+    } catch (URISyntaxException e) {
+      this.callback.handleError(e);
+    }
+  }
+
+  public void upload(MetaGlobalDelegate callback) {
+    try {
+      this.isUploading = true;
+      SyncStorageRecordRequest r = new SyncStorageRecordRequest(this.metaURL);
+
+      r.delegate = this;
+      this.callback = callback;
+      r.put(this.asCryptoRecord());
+    } catch (Exception e) {
+      callback.handleError(e);
+    }
+  }
+
+  protected ExtendedJSONObject asRecordContents() {
+    ExtendedJSONObject json = new ExtendedJSONObject();
+    json.put("storageVersion", storageVersion);
+    json.put("engines", engines);
+    json.put("syncID", syncID);
+    json.put("declined", declined);
+    return json;
+  }
+
+  /**
+   * Return a copy ready for upload.
+   * @return an unencrypted <code>CryptoRecord</code>.
+   */
+  public CryptoRecord asCryptoRecord() {
+    ExtendedJSONObject payload = this.asRecordContents();
+    CryptoRecord record = new CryptoRecord(payload);
+    record.collection = "meta";
+    record.guid       = "global";
+    record.deleted    = false;
+    return record;
+  }
+
+  public void setFromRecord(CryptoRecord record) throws IllegalStateException, IOException, NonObjectJSONException, NonArrayJSONException {
+    if (record == null) {
+      throw new IllegalArgumentException("Cannot set meta/global from null record");
+    }
+    Logger.debug(LOG_TAG, "meta/global is " + record.payload.toJSONString());
+    this.storageVersion = (Long) record.payload.get("storageVersion");
+    this.syncID = (String) record.payload.get("syncID");
+
+    setEngines(record.payload.getObject("engines"));
+
+    // Accepts null -- declined can be missing.
+    setDeclinedEngineNames(record.payload.getArray("declined"));
+  }
+
+  public Long getStorageVersion() {
+    return this.storageVersion;
+  }
+
+  public void setStorageVersion(Long version) {
+    this.storageVersion = version;
+  }
+
+  public ExtendedJSONObject getEngines() {
+    return engines;
+  }
+
+  @SuppressWarnings("unchecked")
+  public void declineEngine(String engine) {
+    if (this.declined == null) {
+      JSONArray replacement = new JSONArray();
+      replacement.add(engine);
+      setDeclinedEngineNames(replacement);
+      return;
+    }
+
+    this.declined.add(engine);
+  }
+
+  @SuppressWarnings("unchecked")
+  public void declineEngineNames(Collection<String> additional) {
+    if (this.declined == null) {
+      JSONArray replacement = new JSONArray();
+      replacement.addAll(additional);
+      setDeclinedEngineNames(replacement);
+      return;
+    }
+
+    for (String engine : additional) {
+      if (!this.declined.contains(engine)) {
+        this.declined.add(engine);
+      }
+    }
+  }
+
+  public void setDeclinedEngineNames(JSONArray declined) {
+    if (declined == null) {
+      this.declined = new JSONArray();
+      return;
+    }
+    this.declined = declined;
+  }
+
+  /**
+   * Return the set of engines that we support (given as an argument)
+   * but the user hasn't explicitly declined on another device.
+   *
+   * Can return the input if the user hasn't declined any engines.
+   */
+  public Set<String> getNonDeclinedEngineNames(Set<String> supported) {
+    if (this.declined == null ||
+        this.declined.isEmpty()) {
+      return supported;
+    }
+
+    final Set<String> result = new HashSet<String>(supported);
+    result.removeAll(this.declined);
+    return result;
+  }
+
+  public void setEngines(ExtendedJSONObject engines) {
+    if (engines == null) {
+      engines = new ExtendedJSONObject();
+    }
+    this.engines = engines;
+    final int count = engines.size();
+    versions   = new HashMap<String, Integer>(count);
+    syncIDs    = new HashMap<String, String>(count);
+    exceptions = new HashMap<String, MetaGlobalException>(count);
+    for (String engineName : engines.keySet()) {
+      try {
+        ExtendedJSONObject engineEntry = engines.getObject(engineName);
+        recordEngineState(engineName, engineEntry);
+      } catch (NonObjectJSONException e) {
+        Logger.error(LOG_TAG, "Engine field for " + engineName + " in meta/global is not an object.");
+        recordEngineState(engineName, new ExtendedJSONObject()); // Doesn't have a version or syncID, for example, so will be server wiped.
+      }
+    }
+  }
+
+  /**
+   * Take a JSON object corresponding to the 'engines' field for the provided engine name,
+   * updating {@link #syncIDs} and {@link #versions} accordingly.
+   *
+   * If the record is malformed, an entry is added to {@link #exceptions}, to be rethrown
+   * during validation.
+   */
+  protected void recordEngineState(String engineName, ExtendedJSONObject engineEntry) {
+    if (engineEntry == null) {
+      throw new IllegalArgumentException("engineEntry cannot be null.");
+    }
+
+    // Record syncID first, so that engines with bad versions are recorded.
+    try {
+      String syncID = engineEntry.getString("syncID");
+      if (syncID == null) {
+        Logger.warn(LOG_TAG, "No syncID for " + engineName + ". Recording exception.");
+        exceptions.put(engineName, new MetaGlobalMalformedSyncIDException());
+      }
+      syncIDs.put(engineName, syncID);
+    } catch (ClassCastException e) {
+      // Malformed syncID on the server. Wipe the server.
+      Logger.warn(LOG_TAG, "Malformed syncID " + engineEntry.get("syncID") +
+                           " for " + engineName + ". Recording exception.");
+      exceptions.put(engineName, new MetaGlobalMalformedSyncIDException());
+    }
+
+    try {
+      Integer version = engineEntry.getIntegerSafely("version");
+      Logger.trace(LOG_TAG, "Engine " + engineName + " has server version " + version);
+      if (version == null ||
+          version == 0) {
+        // Invalid version. Wipe the server.
+        Logger.warn(LOG_TAG, "Malformed version " + version +
+                             " for " + engineName + ". Recording exception.");
+        exceptions.put(engineName, new MetaGlobalMalformedVersionException());
+        return;
+      }
+      versions.put(engineName, version);
+    } catch (NumberFormatException e) {
+      // Invalid version. Wipe the server.
+      Logger.warn(LOG_TAG, "Malformed version " + engineEntry.get("version") +
+                           " for " + engineName + ". Recording exception.");
+      exceptions.put(engineName, new MetaGlobalMalformedVersionException());
+      return;
+    }
+  }
+
+  /**
+   * Get enabled engine names.
+   *
+   * @return a collection of engine names or <code>null</code> if meta/global
+   *         was malformed.
+   */
+  public Set<String> getEnabledEngineNames() {
+    if (engines == null) {
+      return null;
+    }
+    return new HashSet<String>(engines.keySet());
+  }
+
+  @SuppressWarnings("unchecked")
+  public Set<String> getDeclinedEngineNames() {
+    if (declined == null) {
+      return null;
+    }
+    return new HashSet<String>(declined);
+  }
+
+  /**
+   * Returns if the server settings and local settings match.
+   * Throws a specific MetaGlobalException if that's not the case.
+   */
+  public void verifyEngineSettings(String engineName, EngineSettings engineSettings)
+  throws MetaGlobalException {
+
+    // We use syncIDs as our canary.
+    if (syncIDs == null) {
+      throw new IllegalStateException("No meta/global record yet processed.");
+    }
+
+    if (engineSettings == null) {
+      throw new IllegalArgumentException("engineSettings cannot be null.");
+    }
+
+    // First, see if we had a parsing problem.
+    final MetaGlobalException exception = exceptions.get(engineName);
+    if (exception != null) {
+      throw exception;
+    }
+
+    final String syncID = syncIDs.get(engineName);
+    if (syncID == null) {
+      // We have checked engineName against enabled engine names before this, so
+      // we should either have a syncID or an exception for this engine already.
+      throw new IllegalArgumentException("Unknown engine " + engineName);
+    }
+
+    // Since we don't have an exception, and we do have a syncID, we should have a version.
+    final Integer version = versions.get(engineName);
+    if (version > engineSettings.version) {
+      // We're out of date.
+      throw new MetaGlobalException.MetaGlobalStaleClientVersionException(version);
+    }
+
+    if (!syncID.equals(engineSettings.syncID)) {
+      // Our syncID is wrong. Reset client and take the server syncID.
+      throw new MetaGlobalException.MetaGlobalStaleClientSyncIDException(syncID);
+    }
+  }
+
+  public String getSyncID() {
+    return syncID;
+  }
+
+  public void setSyncID(String syncID) {
+    this.syncID = syncID;
+  }
+
+  // SyncStorageRequestDelegate methods for fetching.
+  public String credentials() {
+    return null;
+  }
+
+  @Override
+  public AuthHeaderProvider getAuthHeaderProvider() {
+    return authHeaderProvider;
+  }
+
+  @Override
+  public String ifUnmodifiedSince() {
+    return null;
+  }
+
+  @Override
+  public void handleRequestSuccess(SyncStorageResponse response) {
+    if (this.isUploading) {
+      this.handleUploadSuccess(response);
+    } else {
+      this.handleDownloadSuccess(response);
+    }
+  }
+
+  private void handleUploadSuccess(SyncStorageResponse response) {
+    this.callback.handleSuccess(this, response);
+  }
+
+  private void handleDownloadSuccess(SyncStorageResponse response) {
+    if (response.wasSuccessful()) {
+      try {
+        CryptoRecord record = CryptoRecord.fromJSONRecord(response.jsonObjectBody());
+        this.setFromRecord(record);
+        this.callback.handleSuccess(this, response);
+      } catch (Exception e) {
+        this.callback.handleError(e);
+      }
+      return;
+    }
+    this.callback.handleFailure(response);
+  }
+
+  @Override
+  public void handleRequestFailure(SyncStorageResponse response) {
+    if (response.getStatusCode() == 404) {
+      this.callback.handleMissing(this, response);
+      return;
+    }
+    this.callback.handleFailure(response);
+  }
+
+  @Override
+  public void handleRequestError(Exception e) {
+    this.callback.handleError(e);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobalException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobalException.java
new file mode 100644
index 000000000..bec531d11
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobalException.java
@@ -0,0 +1,45 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+public class MetaGlobalException extends SyncException {
+  private static final long serialVersionUID = -6182315615113508925L;
+
+  public static class MetaGlobalMalformedSyncIDException extends MetaGlobalException {
+    private static final long serialVersionUID = 1L;
+  }
+
+  public static class MetaGlobalMalformedVersionException extends MetaGlobalException {
+    private static final long serialVersionUID = 1L;
+  }
+
+  public static class MetaGlobalOutdatedVersionException extends MetaGlobalException {
+    private static final long serialVersionUID = 1L;
+  }
+
+  public static class MetaGlobalStaleClientVersionException extends MetaGlobalException {
+    private static final long serialVersionUID = 1L;
+    public final int serverVersion;
+    public MetaGlobalStaleClientVersionException(final int version) {
+      this.serverVersion = version;
+    }
+  }
+
+  public static class MetaGlobalStaleClientSyncIDException extends MetaGlobalException {
+    private static final long serialVersionUID = 1L;
+    public final String serverSyncID;
+    public MetaGlobalStaleClientSyncIDException(final String syncID) {
+      this.serverSyncID = syncID;
+    }
+  }
+
+  public static class MetaGlobalEngineStateChangedException extends MetaGlobalException {
+    private static final long serialVersionUID = 1L;
+    public final boolean isEnabled;
+    public MetaGlobalEngineStateChangedException(boolean isEnabled) {
+      this.isEnabled = isEnabled;
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobalMissingEnginesException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobalMissingEnginesException.java
new file mode 100644
index 000000000..91bfd2f76
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobalMissingEnginesException.java
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+public class MetaGlobalMissingEnginesException extends MetaGlobalException {
+  private static final long serialVersionUID = -2662107402622277865L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobalNotSetException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobalNotSetException.java
new file mode 100644
index 000000000..ef059c71d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/MetaGlobalNotSetException.java
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+public class MetaGlobalNotSetException extends MetaGlobalException {
+  private static final long serialVersionUID = 2959032409571832970L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NoCollectionKeysSetException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NoCollectionKeysSetException.java
new file mode 100644
index 000000000..323e355b4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NoCollectionKeysSetException.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.SyncResult;
+
+public class NoCollectionKeysSetException extends SyncException {
+  private static final long serialVersionUID = -6185128075412771120L;
+
+  @Override
+  public void updateStats(GlobalSession globalSession, SyncResult syncResult) {
+    syncResult.stats.numAuthExceptions++;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NodeAuthenticationException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NodeAuthenticationException.java
new file mode 100644
index 000000000..a5cd5f0eb
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NodeAuthenticationException.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.SyncResult;
+
+public class NodeAuthenticationException extends SyncException {
+  private static final long serialVersionUID = 8156745873212364352L;
+
+  @Override
+  public void updateStats(GlobalSession globalSession, SyncResult syncResult) {
+    syncResult.stats.numAuthExceptions++;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NonArrayJSONException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NonArrayJSONException.java
new file mode 100644
index 000000000..554645b11
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NonArrayJSONException.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+public class NonArrayJSONException extends UnexpectedJSONException {
+  private static final long serialVersionUID = 5582918057432365749L;
+
+  public NonArrayJSONException(String detailMessage) {
+    super(detailMessage);
+  }
+
+  public NonArrayJSONException(Throwable throwable) {
+    super(throwable);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NonObjectJSONException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NonObjectJSONException.java
new file mode 100644
index 000000000..fd50d465e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NonObjectJSONException.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+public class NonObjectJSONException extends UnexpectedJSONException {
+  private static final long serialVersionUID = 2214238763035650087L;
+
+  public NonObjectJSONException(String detailMessage) {
+    super(detailMessage);
+  }
+
+  public NonObjectJSONException(Throwable throwable) {
+    super(throwable);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NullClusterURLException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NullClusterURLException.java
new file mode 100644
index 000000000..c1d8833b6
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/NullClusterURLException.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.SyncResult;
+
+public class NullClusterURLException extends SyncException {
+  private static final long serialVersionUID = 4277845518548393161L;
+
+  @Override
+  public void updateStats(GlobalSession globalSession, SyncResult syncResult) {
+    syncResult.stats.numAuthExceptions++;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/PersistedMetaGlobal.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/PersistedMetaGlobal.java
new file mode 100644
index 000000000..d3467545c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/PersistedMetaGlobal.java
@@ -0,0 +1,86 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+
+import android.content.SharedPreferences;
+
+public class PersistedMetaGlobal {
+  public static final String LOG_TAG = "PersistedMetaGlobal";
+
+  public static final String META_GLOBAL_SERVER_RESPONSE_BODY = "metaGlobalServerResponseBody";
+  public static final String META_GLOBAL_LAST_MODIFIED        = "metaGlobalLastModified";
+
+  protected SharedPreferences prefs;
+
+  public PersistedMetaGlobal(SharedPreferences prefs) {
+    this.prefs = prefs;
+  }
+
+  /**
+   * Sets a <code>MetaGlobal</code> from persisted prefs.
+   *
+   * @param metaUrl
+   *          meta/global server URL
+   * @param credentials
+   *          Sync credentials
+   *
+   * @return <MetaGlobal> set from previously fetched meta/global record from
+   *         server
+   */
+  public MetaGlobal metaGlobal(String metaUrl, AuthHeaderProvider authHeaderProvider) {
+    String json = prefs.getString(META_GLOBAL_SERVER_RESPONSE_BODY, null);
+    if (json == null) {
+      return null;
+    }
+    MetaGlobal metaGlobal = null;
+    try {
+      CryptoRecord cryptoRecord = CryptoRecord.fromJSONRecord(json);
+      MetaGlobal mg = new MetaGlobal(metaUrl, authHeaderProvider);
+      mg.setFromRecord(cryptoRecord);
+      metaGlobal = mg;
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception decrypting persisted meta/global.", e);
+    }
+    return metaGlobal;
+  }
+
+  public void persistMetaGlobal(MetaGlobal metaGlobal) {
+    if (metaGlobal == null) {
+      Logger.debug(LOG_TAG, "Clearing persisted meta/global.");
+      prefs.edit().remove(META_GLOBAL_SERVER_RESPONSE_BODY).commit();
+      return;
+    }
+    try {
+      CryptoRecord cryptoRecord = metaGlobal.asCryptoRecord();
+      String json = cryptoRecord.toJSONString();
+      Logger.debug(LOG_TAG, "Persisting meta/global.");
+      prefs.edit().putString(META_GLOBAL_SERVER_RESPONSE_BODY, json).commit();
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception encrypting while persisting meta/global.", e);
+    }
+  }
+
+  public long lastModified() {
+    return prefs.getLong(META_GLOBAL_LAST_MODIFIED, -1);
+  }
+
+  public void persistLastModified(long lastModified) {
+    if (lastModified <= 0) {
+      Logger.debug(LOG_TAG, "Clearing persisted meta/global last modified timestamp.");
+      prefs.edit().remove(META_GLOBAL_LAST_MODIFIED).commit();
+      return;
+    }
+    Logger.debug(LOG_TAG, "Persisting meta/global last modified timestamp " + lastModified + ".");
+    prefs.edit().putLong(META_GLOBAL_LAST_MODIFIED, lastModified).commit();
+  }
+
+  public void purge() {
+    persistLastModified(-1);
+    persistMetaGlobal(null);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/PrefsBackoffHandler.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/PrefsBackoffHandler.java
new file mode 100644
index 000000000..63f6446da
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/PrefsBackoffHandler.java
@@ -0,0 +1,59 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.SharedPreferences;
+import android.content.SharedPreferences.Editor;
+
+public class PrefsBackoffHandler implements BackoffHandler {
+  public static final String PREF_EARLIEST_NEXT = "earliestnext";
+
+  private final SharedPreferences prefs;
+  private final String prefEarliest;
+
+  public PrefsBackoffHandler(final SharedPreferences prefs, final String prefSuffix) {
+    if (prefs == null) {
+      throw new IllegalArgumentException("prefs must not be null.");
+    }
+    this.prefs = prefs;
+    this.prefEarliest = PREF_EARLIEST_NEXT + "." + prefSuffix;
+  }
+
+  @Override
+  public synchronized long getEarliestNextRequest() {
+    return prefs.getLong(prefEarliest, 0);
+  }
+
+  @Override
+  public synchronized void setEarliestNextRequest(final long next) {
+    final Editor edit = prefs.edit();
+    edit.putLong(prefEarliest, next);
+    edit.commit();
+  }
+
+  @Override
+  public synchronized void extendEarliestNextRequest(final long next) {
+    if (prefs.getLong(prefEarliest, 0) >= next) {
+      return;
+    }
+    final Editor edit = prefs.edit();
+    edit.putLong(prefEarliest, next);
+    edit.commit();
+  }
+
+  /**
+   * Return the number of milliseconds until we're allowed to touch the server again,
+   * or 0 if now is fine.
+   */
+  @Override
+  public long delayMilliseconds() {
+    long earliestNextRequest = getEarliestNextRequest();
+    if (earliestNextRequest <= 0) {
+      return 0;
+    }
+    long now = System.currentTimeMillis();
+    return Math.max(0, earliestNextRequest - now);
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/README.txt b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/README.txt
new file mode 100644
index 000000000..cf4624ca4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/README.txt
@@ -0,0 +1 @@
+These files are managed in the android-sync repo. Do not modify directly, or your changes will be lost.
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Server11PreviousPostFailedException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Server11PreviousPostFailedException.java
new file mode 100644
index 000000000..4ea77f37c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Server11PreviousPostFailedException.java
@@ -0,0 +1,12 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+/**
+ * A previous POST failed, so we won't send any more records this session.
+ */
+public class Server11PreviousPostFailedException extends SyncException {
+  private static final long serialVersionUID = -3582490631414624310L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Server11RecordPostFailedException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Server11RecordPostFailedException.java
new file mode 100644
index 000000000..d654d3116
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Server11RecordPostFailedException.java
@@ -0,0 +1,12 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+/**
+ * The server rejected a record in its "failure" array.
+ */
+public class Server11RecordPostFailedException extends SyncException {
+  private static final long serialVersionUID = -8517471217486190314L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SharedPreferencesClientsDataDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SharedPreferencesClientsDataDelegate.java
new file mode 100644
index 000000000..4c1584d5a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SharedPreferencesClientsDataDelegate.java
@@ -0,0 +1,121 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import org.mozilla.gecko.background.fxa.FxAccountUtils;
+import org.mozilla.gecko.fxa.FirefoxAccounts;
+import org.mozilla.gecko.fxa.FxAccountDeviceRegistrator;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.sync.delegates.ClientsDataDelegate;
+import org.mozilla.gecko.util.HardwareUtils;
+
+import android.accounts.Account;
+import android.content.Context;
+import android.content.SharedPreferences;
+
+/**
+ * A <code>ClientsDataDelegate</code> implementation that persists to a
+ * <code>SharedPreferences</code> instance.
+ */
+public class SharedPreferencesClientsDataDelegate implements ClientsDataDelegate {
+  protected final SharedPreferences sharedPreferences;
+  protected final Context context;
+
+  public SharedPreferencesClientsDataDelegate(SharedPreferences sharedPreferences, Context context) {
+    this.sharedPreferences = sharedPreferences;
+    this.context = context;
+
+    // It's safe to init this multiple times.
+    HardwareUtils.init(context);
+  }
+
+  @Override
+  public synchronized String getAccountGUID() {
+    String accountGUID = sharedPreferences.getString(SyncConfiguration.PREF_ACCOUNT_GUID, null);
+    if (accountGUID == null) {
+      accountGUID = Utils.generateGuid();
+      sharedPreferences.edit().putString(SyncConfiguration.PREF_ACCOUNT_GUID, accountGUID).commit();
+    }
+    return accountGUID;
+  }
+
+  private synchronized void saveClientNameToSharedPreferences(String clientName, long now) {
+    sharedPreferences
+            .edit()
+            .putString(SyncConfiguration.PREF_CLIENT_NAME, clientName)
+            .putLong(SyncConfiguration.PREF_CLIENT_DATA_TIMESTAMP, now)
+            .apply();
+  }
+
+  /**
+   * Set client name.
+   *
+   * @param clientName to change to.
+   */
+  @Override
+  public synchronized void setClientName(String clientName, long now) {
+    saveClientNameToSharedPreferences(clientName, now);
+
+    // Update the FxA device registration
+    final Account account = FirefoxAccounts.getFirefoxAccount(context);
+    if (account != null) {
+      final AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+      fxAccount.resetDeviceRegistrationVersion();
+    }
+  }
+
+  @Override
+  public String getDefaultClientName() {
+    return FxAccountUtils.defaultClientName(context);
+  }
+
+  @Override
+  public synchronized String getClientName() {
+    String clientName = sharedPreferences.getString(SyncConfiguration.PREF_CLIENT_NAME, null);
+    if (clientName == null) {
+      clientName = getDefaultClientName();
+      long now = System.currentTimeMillis();
+      saveClientNameToSharedPreferences(clientName, now); // Save locally only to avoid a recursion loop
+    }
+    return clientName;
+  }
+
+  @Override
+  public synchronized void setClientsCount(int clientsCount) {
+    sharedPreferences.edit().putLong(SyncConfiguration.PREF_NUM_CLIENTS, clientsCount).commit();
+  }
+
+  @Override
+  public boolean isLocalGUID(String guid) {
+    return getAccountGUID().equals(guid);
+  }
+
+  @Override
+  public synchronized int getClientsCount() {
+    return (int) sharedPreferences.getLong(SyncConfiguration.PREF_NUM_CLIENTS, 0);
+  }
+
+  @Override
+  public long getLastModifiedTimestamp() {
+    return sharedPreferences.getLong(SyncConfiguration.PREF_CLIENT_DATA_TIMESTAMP, 0);
+  }
+
+  @Override
+  public String getFormFactor() {
+    if (HardwareUtils.isLargeTablet()) {
+      return "largetablet";
+    }
+
+    if (HardwareUtils.isSmallTablet()) {
+      return "smalltablet";
+    }
+
+    if (HardwareUtils.isTelevision()) {
+      return "tv";
+    }
+
+    return "phone";
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Sync11Configuration.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Sync11Configuration.java
new file mode 100644
index 000000000..4b2280895
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Sync11Configuration.java
@@ -0,0 +1,84 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.net.URI;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+
+import android.content.SharedPreferences;
+import android.content.SharedPreferences.Editor;
+
+/**
+ * Override SyncConfiguration to restore the old behavior of clusterURL --
+ * that is, a URL without the protocol version etc.
+ *
+ */
+public class Sync11Configuration extends SyncConfiguration {
+  private static final String LOG_TAG = "Sync11Configuration";
+  private static final String API_VERSION = "1.1";
+
+  public Sync11Configuration(String username,
+                             AuthHeaderProvider authHeaderProvider,
+                             SharedPreferences prefs) {
+    super(username, authHeaderProvider, prefs);
+  }
+
+  public Sync11Configuration(String username,
+                             AuthHeaderProvider authHeaderProvider,
+                             SharedPreferences prefs,
+                             KeyBundle keyBundle) {
+    super(username, authHeaderProvider, prefs, keyBundle);
+  }
+
+  @Override
+  public String getAPIVersion() {
+    return API_VERSION;
+  }
+
+  @Override
+  public String storageURL() {
+    return clusterURL + API_VERSION + "/" + username + "/storage";
+  }
+
+  @Override
+  protected String infoBaseURL() {
+    return clusterURL + API_VERSION + "/" + username + "/info/";
+  }
+
+  protected void setAndPersistClusterURL(URI u, SharedPreferences prefs) {
+    boolean shouldPersist = (prefs != null) && (clusterURL == null);
+
+    Logger.trace(LOG_TAG, "Setting cluster URL to " + u.toASCIIString() +
+                          (shouldPersist ? ". Persisting." : ". Not persisting."));
+    clusterURL = u;
+    if (shouldPersist) {
+      Editor edit = prefs.edit();
+      edit.putString(PREF_CLUSTER_URL, clusterURL.toASCIIString());
+      edit.commit();
+    }
+  }
+
+  protected void setClusterURL(URI u, SharedPreferences prefs) {
+    if (u == null) {
+      Logger.warn(LOG_TAG, "Refusing to set cluster URL to null.");
+      return;
+    }
+    URI uri = u.normalize();
+    if (uri.toASCIIString().endsWith("/")) {
+      setAndPersistClusterURL(u, prefs);
+      return;
+    }
+    setAndPersistClusterURL(uri.resolve("/"), prefs);
+    Logger.trace(LOG_TAG, "Set cluster URL to " + clusterURL.toASCIIString() + ", given input " + u.toASCIIString());
+  }
+
+  @Override
+  public void setClusterURL(URI u) {
+    setClusterURL(u, this.getPrefs());
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncConfiguration.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncConfiguration.java
new file mode 100644
index 000000000..53edf5f84
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncConfiguration.java
@@ -0,0 +1,480 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.mozilla.gecko.background.common.PrefsBranch;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.crypto.PersistedCrypto5Keys;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.stage.GlobalSyncStage.Stage;
+
+import android.content.SharedPreferences;
+import android.content.SharedPreferences.Editor;
+
+public class SyncConfiguration {
+  private static final String LOG_TAG = "SyncConfiguration";
+
+  // These must be set in GlobalSession's constructor.
+  public URI             clusterURL;
+  public KeyBundle       syncKeyBundle;
+
+  public InfoConfiguration infoConfiguration;
+
+  public CollectionKeys  collectionKeys;
+  public InfoCollections infoCollections;
+  public MetaGlobal      metaGlobal;
+  public String          syncID;
+
+  protected final String username;
+
+  /**
+   * Persisted collection of enabledEngineNames.
+   * <p>
+   * Can contain engines Android Sync is not currently aware of, such as "prefs"
+   * or "addons".
+   * <p>
+   * Copied from latest downloaded meta/global record and used to generate a
+   * fresh meta/global record for upload.
+   */
+  public Set<String> enabledEngineNames;
+  public Set<String> declinedEngineNames = new HashSet<String>();
+
+  /**
+   * Names of stages to sync <it>this sync</it>, or <code>null</code> to sync
+   * all known stages.
+   * <p>
+   * Generated <it>each sync</it> from extras bundle passed to
+   * <code>SyncAdapter.onPerformSync</code> and not persisted.
+   * <p>
+   * Not synchronized! Set this exactly once per global session and don't modify
+   * it -- especially not from multiple threads.
+   */
+  public Collection<String> stagesToSync;
+
+  /**
+   * Engines whose sync state has been modified by the user through
+   * SelectEnginesActivity, where each key-value pair is an engine name and
+   * its sync state.
+   *
+   * This differs from <code>enabledEngineNames</code> in that
+   * <code>enabledEngineNames</code> reflects the downloaded meta/global,
+   * whereas <code>userSelectedEngines</code> stores the differences in engines to
+   * sync that the user has selected.
+   *
+   * Each engine stage will check for engine changes at the beginning of the
+   * stage.
+   *
+   * If no engine sync state changes have been made by the user, userSelectedEngines
+   * will be null, and Sync will proceed normally.
+   *
+   * If the user has made changes to engine syncing state, each engine will sync
+   * according to the sync state specified in userSelectedEngines and propagate that
+   * state to meta/global, to be uploaded.
+   */
+  public Map<String, Boolean> userSelectedEngines;
+  public long userSelectedEnginesTimestamp;
+
+  public SharedPreferences prefs;
+
+  protected final AuthHeaderProvider authHeaderProvider;
+
+  public static final String PREF_PREFS_VERSION = "prefs.version";
+  public static final long CURRENT_PREFS_VERSION = 1;
+
+  public static final String CLIENTS_COLLECTION_TIMESTAMP = "serverClientsTimestamp";  // When the collection was touched.
+  public static final String CLIENT_RECORD_TIMESTAMP = "serverClientRecordTimestamp";  // When our record was touched.
+  public static final String MIGRATION_SENTINEL_CHECK_TIMESTAMP = "migrationSentinelCheckTimestamp";  // When we last looked in meta/fxa_credentials.
+
+  public static final String PREF_CLUSTER_URL = "clusterURL";
+  public static final String PREF_SYNC_ID = "syncID";
+
+  public static final String PREF_ENABLED_ENGINE_NAMES = "enabledEngineNames";
+  public static final String PREF_DECLINED_ENGINE_NAMES = "declinedEngineNames";
+  public static final String PREF_USER_SELECTED_ENGINES_TO_SYNC = "userSelectedEngines";
+  public static final String PREF_USER_SELECTED_ENGINES_TO_SYNC_TIMESTAMP = "userSelectedEnginesTimestamp";
+
+  public static final String PREF_CLUSTER_URL_IS_STALE = "clusterurlisstale";
+
+  public static final String PREF_ACCOUNT_GUID = "account.guid";
+  public static final String PREF_CLIENT_NAME = "account.clientName";
+  public static final String PREF_NUM_CLIENTS = "account.numClients";
+  public static final String PREF_CLIENT_DATA_TIMESTAMP = "account.clientDataTimestamp";
+
+  private static final String API_VERSION = "1.5";
+
+  public SyncConfiguration(String username, AuthHeaderProvider authHeaderProvider, SharedPreferences prefs) {
+    this.username = username;
+    this.authHeaderProvider = authHeaderProvider;
+    this.prefs = prefs;
+    this.loadFromPrefs(prefs);
+  }
+
+  public SyncConfiguration(String username, AuthHeaderProvider authHeaderProvider, SharedPreferences prefs, KeyBundle syncKeyBundle) {
+    this(username, authHeaderProvider, prefs);
+    this.syncKeyBundle = syncKeyBundle;
+  }
+
+  public String getAPIVersion() {
+    return API_VERSION;
+  }
+
+  public SharedPreferences getPrefs() {
+    return this.prefs;
+  }
+
+  /**
+   * Valid engines supported by Android Sync.
+   *
+   * @return Set<String> of valid engine names that Android Sync implements.
+   */
+  public static Set<String> validEngineNames() {
+    Set<String> engineNames = new HashSet<String>();
+    for (Stage stage : Stage.getNamedStages()) {
+      engineNames.add(stage.getRepositoryName());
+    }
+    return engineNames;
+  }
+
+  /**
+   * Return a convenient accessor for part of prefs.
+   * @return
+   *        A PrefsBranch object representing this
+   *        section of the preferences space.
+   */
+  public PrefsBranch getBranch(String prefix) {
+    return new PrefsBranch(this.getPrefs(), prefix);
+  }
+
+  /**
+   * Gets the engine names that are enabled, declined, or other (depending on pref) in meta/global.
+   *
+   * @param prefs
+   *          SharedPreferences that the engines are associated with.
+   * @param pref
+   *          The preference name to use. E.g, PREF_ENABLED_ENGINE_NAMES.
+   * @return Set<String> of the enabled engine names if they have been stored,
+   *         or null otherwise.
+   */
+  protected static Set<String> getEngineNamesFromPref(SharedPreferences prefs, String pref) {
+    final String json = prefs.getString(pref, null);
+    if (json == null) {
+      return null;
+    }
+    try {
+      final ExtendedJSONObject o = new ExtendedJSONObject(json);
+      return new HashSet<String>(o.keySet());
+    } catch (Exception e) {
+      return null;
+    }
+  }
+
+  /**
+   * Returns the set of engine names that the user has enabled. If none
+   * have been stored in prefs, <code>null</code> is returned.
+   */
+  public static Set<String> getEnabledEngineNames(SharedPreferences prefs) {
+      return getEngineNamesFromPref(prefs, PREF_ENABLED_ENGINE_NAMES);
+  }
+
+  /**
+   * Returns the set of engine names that the user has declined.
+   */
+  public static Set<String> getDeclinedEngineNames(SharedPreferences prefs) {
+    final Set<String> names = getEngineNamesFromPref(prefs, PREF_DECLINED_ENGINE_NAMES);
+    if (names == null) {
+        return new HashSet<String>();
+    }
+    return names;
+  }
+
+  /**
+   * Gets the engines whose sync states have been changed by the user through the
+   * SelectEnginesActivity.
+   *
+   * @param prefs
+   *          SharedPreferences of account that the engines are associated with.
+   * @return Map<String, Boolean> of changed engines. Key is the lower-cased
+   *         engine name, Value is the new sync state.
+   */
+  public static Map<String, Boolean> getUserSelectedEngines(SharedPreferences prefs) {
+    String json = prefs.getString(PREF_USER_SELECTED_ENGINES_TO_SYNC, null);
+    if (json == null) {
+      return null;
+    }
+    try {
+      ExtendedJSONObject o = new ExtendedJSONObject(json);
+      Map<String, Boolean> map = new HashMap<String, Boolean>();
+      for (Entry<String, Object> e : o.entrySet()) {
+        String key = e.getKey();
+        Boolean value = (Boolean) e.getValue();
+        map.put(key, value);
+        // Forms depends on history. Add forms if history is selected.
+        if ("history".equals(key)) {
+          map.put("forms", value);
+        }
+      }
+      // Sanity check: remove forms if history does not exist.
+      if (!map.containsKey("history")) {
+        map.remove("forms");
+      }
+      return map;
+    } catch (Exception e) {
+      return null;
+    }
+  }
+
+  /**
+   * Store a Map of engines and their sync states to prefs.
+   *
+   * Any engine that's disabled in the input is also recorded
+   * as a declined engine, overwriting the stored values.
+   *
+   * @param prefs
+   *          SharedPreferences that the engines are associated with.
+   * @param selectedEngines
+   *          Map<String, Boolean> of engine name to sync state
+   */
+  public static void storeSelectedEnginesToPrefs(SharedPreferences prefs, Map<String, Boolean> selectedEngines) {
+    ExtendedJSONObject jObj = new ExtendedJSONObject();
+    HashSet<String> declined = new HashSet<String>();
+    for (Entry<String, Boolean> e : selectedEngines.entrySet()) {
+      final Boolean enabled = e.getValue();
+      final String engine = e.getKey();
+      jObj.put(engine, enabled);
+      if (!enabled) {
+        declined.add(engine);
+      }
+    }
+
+    // Our history checkbox drives form history, too.
+    // We don't need to do this for enablement: that's done at retrieval time.
+    if (selectedEngines.containsKey("history") && !selectedEngines.get("history")) {
+      declined.add("forms");
+    }
+
+    String json = jObj.toJSONString();
+    long currentTime = System.currentTimeMillis();
+    Editor edit = prefs.edit();
+    edit.putString(PREF_USER_SELECTED_ENGINES_TO_SYNC, json);
+    edit.putString(PREF_DECLINED_ENGINE_NAMES, setToJSONObjectString(declined));
+    edit.putLong(PREF_USER_SELECTED_ENGINES_TO_SYNC_TIMESTAMP, currentTime);
+    Logger.error(LOG_TAG, "Storing user-selected engines at [" + currentTime + "].");
+    edit.commit();
+  }
+
+  public void loadFromPrefs(SharedPreferences prefs) {
+    if (prefs.contains(PREF_CLUSTER_URL)) {
+      String u = prefs.getString(PREF_CLUSTER_URL, null);
+      try {
+        clusterURL = new URI(u);
+        Logger.trace(LOG_TAG, "Set clusterURL from bundle: " + u);
+      } catch (URISyntaxException e) {
+        Logger.warn(LOG_TAG, "Ignoring bundle clusterURL (" + u + "): invalid URI.", e);
+      }
+    }
+    if (prefs.contains(PREF_SYNC_ID)) {
+      syncID = prefs.getString(PREF_SYNC_ID, null);
+      Logger.trace(LOG_TAG, "Set syncID from bundle: " + syncID);
+    }
+    enabledEngineNames = getEnabledEngineNames(prefs);
+    declinedEngineNames = getDeclinedEngineNames(prefs);
+    userSelectedEngines = getUserSelectedEngines(prefs);
+    userSelectedEnginesTimestamp = prefs.getLong(PREF_USER_SELECTED_ENGINES_TO_SYNC_TIMESTAMP, 0);
+    // We don't set crypto/keys here because we need the syncKeyBundle to decrypt the JSON
+    // and we won't have it on construction.
+    // TODO: MetaGlobal, password, infoCollections.
+  }
+
+  public void persistToPrefs() {
+    this.persistToPrefs(this.getPrefs());
+  }
+
+  private static String setToJSONObjectString(Set<String> set) {
+    ExtendedJSONObject o = new ExtendedJSONObject();
+    for (String name : set) {
+      o.put(name, 0);
+    }
+    return o.toJSONString();
+  }
+
+  public void persistToPrefs(SharedPreferences prefs) {
+    Editor edit = prefs.edit();
+    if (clusterURL == null) {
+      edit.remove(PREF_CLUSTER_URL);
+    } else {
+      edit.putString(PREF_CLUSTER_URL, clusterURL.toASCIIString());
+    }
+    if (syncID != null) {
+      edit.putString(PREF_SYNC_ID, syncID);
+    }
+    if (enabledEngineNames == null) {
+      edit.remove(PREF_ENABLED_ENGINE_NAMES);
+    } else {
+      edit.putString(PREF_ENABLED_ENGINE_NAMES, setToJSONObjectString(enabledEngineNames));
+    }
+    if (declinedEngineNames == null || declinedEngineNames.isEmpty()) {
+      edit.remove(PREF_DECLINED_ENGINE_NAMES);
+    } else {
+      edit.putString(PREF_DECLINED_ENGINE_NAMES, setToJSONObjectString(declinedEngineNames));
+    }
+    if (userSelectedEngines == null) {
+      edit.remove(PREF_USER_SELECTED_ENGINES_TO_SYNC);
+      edit.remove(PREF_USER_SELECTED_ENGINES_TO_SYNC_TIMESTAMP);
+    }
+    // Don't bother saving userSelectedEngines - these should only be changed by
+    // SelectEnginesActivity.
+    edit.commit();
+    // TODO: keys.
+  }
+
+  public AuthHeaderProvider getAuthHeaderProvider() {
+    return authHeaderProvider;
+  }
+
+  public CollectionKeys getCollectionKeys() {
+    return collectionKeys;
+  }
+
+  public void setCollectionKeys(CollectionKeys k) {
+    collectionKeys = k;
+  }
+
+  /**
+   * Return path to storage endpoint without trailing slash.
+   *
+   * @return storage endpoint without trailing slash.
+   */
+  public String storageURL() {
+    return clusterURL + "/storage";
+  }
+
+  protected String infoBaseURL() {
+    return clusterURL + "/info/";
+  }
+
+  public String infoCollectionsURL() {
+    return infoBaseURL() + "collections";
+  }
+
+  public String infoConfigurationURL() {
+    return infoBaseURL() + "configuration";
+  }
+
+  public String infoCollectionCountsURL() {
+    return infoBaseURL() + "collection_counts";
+  }
+
+  public String metaURL() {
+    return storageURL() + "/meta/global";
+  }
+
+  public URI collectionURI(String collection) throws URISyntaxException {
+    return new URI(storageURL() + "/" + collection);
+  }
+
+  public URI collectionURI(String collection, boolean full) throws URISyntaxException {
+    // Do it this way to make it easier to add more params later.
+    // It's pretty ugly, I'll grant.
+    boolean anyParams = full;
+    String  uriParams = "";
+    if (anyParams) {
+      StringBuilder params = new StringBuilder("?");
+      if (full) {
+        params.append("full=1");
+      }
+      uriParams = params.toString();
+    }
+    String uri = storageURL() + "/" + collection + uriParams;
+    return new URI(uri);
+  }
+
+  public URI wboURI(String collection, String id) throws URISyntaxException {
+    return new URI(storageURL() + "/" + collection + "/" + id);
+  }
+
+  public URI keysURI() throws URISyntaxException {
+    return wboURI("crypto", "keys");
+  }
+
+  public URI getClusterURL() {
+    return clusterURL;
+  }
+
+  public String getClusterURLString() {
+    if (clusterURL == null) {
+      return null;
+    }
+    return clusterURL.toASCIIString();
+  }
+
+  public void setClusterURL(URI u) {
+    this.clusterURL = u;
+  }
+
+  /**
+   * Used for direct management of related prefs.
+   */
+  public Editor getEditor() {
+    return this.getPrefs().edit();
+  }
+
+  /**
+   * We persist two different clients timestamps: our own record's,
+   * and the timestamp for the collection.
+   */
+  public void persistServerClientRecordTimestamp(long timestamp) {
+    getEditor().putLong(SyncConfiguration.CLIENT_RECORD_TIMESTAMP, timestamp).commit();
+  }
+
+  public long getPersistedServerClientRecordTimestamp() {
+    return getPrefs().getLong(SyncConfiguration.CLIENT_RECORD_TIMESTAMP, 0L);
+  }
+
+  public void persistServerClientsTimestamp(long timestamp) {
+    getEditor().putLong(SyncConfiguration.CLIENTS_COLLECTION_TIMESTAMP, timestamp).commit();
+  }
+
+  public long getPersistedServerClientsTimestamp() {
+    return getPrefs().getLong(SyncConfiguration.CLIENTS_COLLECTION_TIMESTAMP, 0L);
+  }
+
+  public void persistLastMigrationSentinelCheckTimestamp(long timestamp) {
+    getEditor().putLong(SyncConfiguration.MIGRATION_SENTINEL_CHECK_TIMESTAMP, timestamp).commit();
+  }
+
+  public long getLastMigrationSentinelCheckTimestamp() {
+    return getPrefs().getLong(SyncConfiguration.MIGRATION_SENTINEL_CHECK_TIMESTAMP, 0L);
+  }
+
+  public void purgeCryptoKeys() {
+    if (collectionKeys != null) {
+      collectionKeys.clear();
+    }
+    persistedCryptoKeys().purge();
+  }
+
+  public void purgeMetaGlobal() {
+    metaGlobal = null;
+    persistedMetaGlobal().purge();
+  }
+
+  public PersistedCrypto5Keys persistedCryptoKeys() {
+    return new PersistedCrypto5Keys(getPrefs(), syncKeyBundle);
+  }
+
+  public PersistedMetaGlobal persistedMetaGlobal() {
+    return new PersistedMetaGlobal(getPrefs());
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncConfigurationException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncConfigurationException.java
new file mode 100644
index 000000000..02ba118c5
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncConfigurationException.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.SyncResult;
+
+public class SyncConfigurationException extends SyncException {
+  private static final long serialVersionUID = 1107080177269358381L;
+
+  @Override
+  public void updateStats(GlobalSession globalSession, SyncResult syncResult) {
+    syncResult.stats.numAuthExceptions++;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncConstants.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncConstants.java
new file mode 100644
index 000000000..5dc7b289f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncConstants.java
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import org.mozilla.gecko.AppConstants;
+
+public class SyncConstants {
+  public static final String GLOBAL_LOG_TAG = "FxSync";
+  public static final String SYNC_MAJOR_VERSION  = "1";
+  public static final String SYNC_MINOR_VERSION  = "0";
+  public static final String SYNC_VERSION_STRING = SYNC_MAJOR_VERSION + "." +
+                                                   AppConstants.MOZ_APP_VERSION + "." +
+                                                   SYNC_MINOR_VERSION;
+
+  public static final String USER_AGENT = "Firefox AndroidSync " +
+                                          SYNC_VERSION_STRING + " (" +
+                                          AppConstants.MOZ_APP_UA_NAME + ")";
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncException.java
new file mode 100644
index 000000000..ee0902568
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SyncException.java
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.SyncResult;
+
+public abstract class SyncException extends Exception {
+  private static final long serialVersionUID = -6928990004393234738L;
+
+  public SyncException() {
+    super();
+  }
+
+  public SyncException(final Throwable e) {
+    super(e);
+  }
+
+  /**
+   * Update sync result statistics with information particular to this
+   * exception.
+   *
+   * @param globalSession
+   *          current session, or null.
+   * @param syncResult
+   *          Android sync result to update.
+   */
+  public void updateStats(GlobalSession globalSession, SyncResult syncResult) {
+    // Assume storage error.
+    // TODO: this logic is overly simplistic.
+    syncResult.databaseError = true;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SynchronizerConfiguration.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SynchronizerConfiguration.java
new file mode 100644
index 000000000..2b08be9c4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/SynchronizerConfiguration.java
@@ -0,0 +1,68 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import android.content.SharedPreferences.Editor;
+
+import org.mozilla.gecko.background.common.PrefsBranch;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.RepositorySessionBundle;
+
+import java.io.IOException;
+
+public class SynchronizerConfiguration {
+  private static final String LOG_TAG = "SynczrConfiguration";
+
+  public String syncID;
+  public RepositorySessionBundle remoteBundle;
+  public RepositorySessionBundle localBundle;
+
+  public SynchronizerConfiguration(PrefsBranch config) throws NonObjectJSONException, IOException {
+    this.load(config);
+  }
+
+  public SynchronizerConfiguration(String syncID, RepositorySessionBundle remoteBundle, RepositorySessionBundle localBundle) {
+    this.syncID       = syncID;
+    this.remoteBundle = remoteBundle;
+    this.localBundle  = localBundle;
+  }
+
+  // This should get partly shuffled back into SyncConfiguration, I think.
+  public void load(PrefsBranch config) throws NonObjectJSONException, IOException {
+    if (config == null) {
+      throw new IllegalArgumentException("config cannot be null.");
+    }
+    String remoteJSON = config.getString("remote", null);
+    String localJSON  = config.getString("local",  null);
+    RepositorySessionBundle rB = new RepositorySessionBundle(remoteJSON);
+    RepositorySessionBundle lB = new RepositorySessionBundle(localJSON);
+    if (remoteJSON == null) {
+      rB.setTimestamp(0);
+    }
+    if (localJSON == null) {
+      lB.setTimestamp(0);
+    }
+    syncID = config.getString("syncID", null);
+    remoteBundle = rB;
+    localBundle  = lB;
+    Logger.debug(LOG_TAG, "Loaded SynchronizerConfiguration. syncID: " + syncID + ", remoteBundle: " + remoteBundle + ", localBundle: " + localBundle);
+  }
+
+  public void persist(PrefsBranch config) {
+    if (config == null) {
+      throw new IllegalArgumentException("config cannot be null.");
+    }
+    String jsonRemote = remoteBundle.toJSONString();
+    String jsonLocal  = localBundle.toJSONString();
+    Editor editor = config.edit();
+    editor.putString("remote", jsonRemote);
+    editor.putString("local",  jsonLocal);
+    editor.putString("syncID", syncID);
+
+    // Synchronous.
+    editor.commit();
+    Logger.debug(LOG_TAG, "Persisted SynchronizerConfiguration. syncID: " + syncID + ", remoteBundle: " + remoteBundle + ", localBundle: " + localBundle);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/ThreadPool.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/ThreadPool.java
new file mode 100644
index 000000000..7f2029566
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/ThreadPool.java
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+public class ThreadPool {
+  public static ExecutorService executorService = Executors.newCachedThreadPool();
+  public static void run(Runnable runnable) {
+    executorService.submit(runnable);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/UnexpectedJSONException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/UnexpectedJSONException.java
new file mode 100644
index 000000000..e5771452c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/UnexpectedJSONException.java
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+public class UnexpectedJSONException extends Exception {
+  private static final long serialVersionUID = 4797570033096443169L;
+
+  public UnexpectedJSONException(String detailMessage) {
+    super(detailMessage);
+  }
+
+  public UnexpectedJSONException(Throwable throwable) {
+    super(throwable);
+  }
+
+  public static class BadRequiredFieldJSONException extends UnexpectedJSONException {
+    private static final long serialVersionUID = -9207736984784497612L;
+
+    public BadRequiredFieldJSONException(String string) {
+      super(string);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/UnknownSynchronizerConfigurationVersionException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/UnknownSynchronizerConfigurationVersionException.java
new file mode 100644
index 000000000..e2350095e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/UnknownSynchronizerConfigurationVersionException.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+public class UnknownSynchronizerConfigurationVersionException extends
+    SyncConfigurationException {
+  public int badVersion;
+  private static final long serialVersionUID = -8497255862099517395L;
+
+  public UnknownSynchronizerConfigurationVersionException(int version) {
+    super();
+    badVersion = version;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Utils.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Utils.java
new file mode 100644
index 000000000..ef8859b4a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/Utils.java
@@ -0,0 +1,575 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync;
+
+import java.io.BufferedReader;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.UnsupportedEncodingException;
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.net.URLDecoder;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import java.text.DecimalFormat;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.concurrent.Executor;
+
+import org.json.simple.JSONArray;
+import org.mozilla.apache.commons.codec.binary.Base32;
+import org.mozilla.apache.commons.codec.binary.Base64;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.nativecode.NativeCrypto;
+import org.mozilla.gecko.sync.setup.Constants;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.os.Bundle;
+
+public class Utils {
+
+  private static final String LOG_TAG = "Utils";
+
+  private static final SecureRandom sharedSecureRandom = new SecureRandom();
+
+  // See <http://developer.android.com/reference/android/content/Context.html#getSharedPreferences%28java.lang.String,%20int%29>
+  public static final int SHARED_PREFERENCES_MODE = 0;
+
+  public static String generateGuid() {
+    byte[] encodedBytes = Base64.encodeBase64(generateRandomBytes(9), false);
+    return new String(encodedBytes).replace("+", "-").replace("/", "_");
+  }
+
+  /**
+   * Helper to generate secure random bytes.
+   *
+   * @param length
+   *        Number of bytes to generate.
+   */
+  public static byte[] generateRandomBytes(int length) {
+    byte[] bytes = new byte[length];
+    sharedSecureRandom.nextBytes(bytes);
+    return bytes;
+  }
+
+  /**
+   * Helper to generate a random integer in a specified range.
+   *
+   * @param r
+   *        Generate an integer between 0 and r-1 inclusive.
+   */
+  public static BigInteger generateBigIntegerLessThan(BigInteger r) {
+    int maxBytes = (int) Math.ceil(((double) r.bitLength()) / 8);
+    BigInteger randInt = new BigInteger(generateRandomBytes(maxBytes));
+    return randInt.mod(r);
+  }
+
+  /**
+   * Helper to convert a byte array to a hex-encoded string
+   */
+  public static String byte2Hex(final byte[] b) {
+    return byte2Hex(b, 2 * b.length);
+  }
+
+  public static String byte2Hex(final byte[] b, int hexLength) {
+    final StringBuilder hs = new StringBuilder(Math.max(2*b.length, hexLength));
+    String stmp;
+
+    for (int n = 0; n < hexLength - 2*b.length; n++) {
+      hs.append("0");
+    }
+
+    for (int n = 0; n < b.length; n++) {
+      stmp = Integer.toHexString(b[n] & 0XFF);
+
+      if (stmp.length() == 1) {
+        hs.append("0");
+      }
+      hs.append(stmp);
+    }
+
+    return hs.toString();
+  }
+
+  public static byte[] concatAll(byte[] first, byte[]... rest) {
+    int totalLength = first.length;
+    for (byte[] array : rest) {
+      totalLength += array.length;
+    }
+
+    byte[] result = new byte[totalLength];
+    int offset = first.length;
+
+    System.arraycopy(first, 0, result, 0, offset);
+
+    for (byte[] array : rest) {
+      System.arraycopy(array, 0, result, offset, array.length);
+      offset += array.length;
+    }
+    return result;
+  }
+
+  /**
+   * Utility for Base64 decoding. Should ensure that the correct
+   * Apache Commons version is used.
+   *
+   * @param base64
+   *        An input string. Will be decoded as UTF-8.
+   * @return
+   *        A byte array of decoded values.
+   * @throws UnsupportedEncodingException
+   *         Should not occur.
+   */
+  public static byte[] decodeBase64(String base64) throws UnsupportedEncodingException {
+    return Base64.decodeBase64(base64.getBytes("UTF-8"));
+  }
+
+  public static byte[] decodeFriendlyBase32(String base32) {
+    Base32 converter = new Base32();
+    final String translated = base32.replace('8', 'l').replace('9', 'o');
+    return converter.decode(translated.toUpperCase(Locale.US));
+  }
+
+  public static byte[] hex2Byte(String str, int byteLength) {
+    byte[] second = hex2Byte(str);
+    if (second.length >= byteLength) {
+      return second;
+    }
+    // New Java arrays are zeroed:
+    // http://docs.oracle.com/javase/specs/jls/se7/html/jls-4.html#jls-4.12.5
+    byte[] first = new byte[byteLength - second.length];
+    return Utils.concatAll(first, second);
+  }
+
+  public static byte[] hex2Byte(String str) {
+    if (str.length() % 2 == 1) {
+      str = "0" + str;
+    }
+
+    byte[] bytes = new byte[str.length() / 2];
+    for (int i = 0; i < bytes.length; i++) {
+      bytes[i] = (byte) Integer.parseInt(str.substring(2 * i, 2 * i + 2), 16);
+    }
+    return bytes;
+  }
+
+  public static String millisecondsToDecimalSecondsString(long ms) {
+    return millisecondsToDecimalSeconds(ms).toString();
+  }
+
+  // For dumping into JSON without quotes.
+  public static BigDecimal millisecondsToDecimalSeconds(long ms) {
+    return new BigDecimal(ms).movePointLeft(3);
+  }
+
+  // This lives until Bug 708956 lands, and we don't have to do it any more.
+  public static long decimalSecondsToMilliseconds(String decimal) {
+    try {
+      return new BigDecimal(decimal).movePointRight(3).longValue();
+    } catch (Exception e) {
+      return -1;
+    }
+  }
+
+  // Oh, Java.
+  public static long decimalSecondsToMilliseconds(Double decimal) {
+    // Truncates towards 0.
+    return (long)(decimal * 1000);
+  }
+
+  public static long decimalSecondsToMilliseconds(Long decimal) {
+    return decimal * 1000;
+  }
+
+  public static long decimalSecondsToMilliseconds(Integer decimal) {
+    return (decimal * 1000);
+  }
+
+  public static byte[] sha256(byte[] in)
+      throws NoSuchAlgorithmException {
+    MessageDigest sha1 = MessageDigest.getInstance("SHA-256");
+    return sha1.digest(in);
+  }
+
+  protected static byte[] sha1(final String utf8)
+      throws NoSuchAlgorithmException, UnsupportedEncodingException {
+    final byte[] bytes = utf8.getBytes("UTF-8");
+    try {
+      return NativeCrypto.sha1(bytes);
+    } catch (final LinkageError e) {
+      // This will throw UnsatisifiedLinkError (missing mozglue) the first time it is called, and
+      // ClassNotDefFoundError, for the uninitialized NativeCrypto class, each subsequent time this
+      // is called; LinkageError is their common ancestor.
+      Logger.warn(LOG_TAG, "Got throwable stretching password using native sha1 implementation; " +
+          "ignoring and using Java implementation.", e);
+      final MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
+      return sha1.digest(utf8.getBytes("UTF-8"));
+    }
+  }
+
+  protected static String sha1Base32(final String utf8)
+      throws NoSuchAlgorithmException, UnsupportedEncodingException {
+    return new Base32().encodeAsString(sha1(utf8)).toLowerCase(Locale.US);
+  }
+
+  /**
+   * If we encounter characters not allowed by the API (as found for
+   * instance in an email address), hash the value.
+   * @param account
+   *        An account string.
+   * @return
+   *        An acceptable string.
+   * @throws UnsupportedEncodingException
+   * @throws NoSuchAlgorithmException
+   */
+  public static String usernameFromAccount(final String account) throws NoSuchAlgorithmException, UnsupportedEncodingException {
+    if (account == null || account.equals("")) {
+      throw new IllegalArgumentException("No account name provided.");
+    }
+    if (account.matches("^[A-Za-z0-9._-]+$")) {
+      return account.toLowerCase(Locale.US);
+    }
+    return sha1Base32(account.toLowerCase(Locale.US));
+  }
+
+  public static SharedPreferences getSharedPreferences(final Context context, final String product, final String username, final String serverURL, final String profile, final long version)
+      throws NoSuchAlgorithmException, UnsupportedEncodingException {
+    String prefsPath = getPrefsPath(product, username, serverURL, profile, version);
+    return context.getSharedPreferences(prefsPath, SHARED_PREFERENCES_MODE);
+  }
+
+  /**
+   * Get shared preferences path for a Sync account.
+   *
+   * @param product the Firefox Sync product package name (like "org.mozilla.firefox").
+   * @param username the Sync account name, optionally encoded with <code>Utils.usernameFromAccount</code>.
+   * @param serverURL the Sync account server URL.
+   * @param profile the Firefox profile name.
+   * @param version the version of preferences to reference.
+   * @return the path.
+   * @throws NoSuchAlgorithmException
+   * @throws UnsupportedEncodingException
+   */
+  public static String getPrefsPath(final String product, final String username, final String serverURL, final String profile, final long version)
+      throws NoSuchAlgorithmException, UnsupportedEncodingException {
+    final String encodedAccount = sha1Base32(serverURL + ":" + usernameFromAccount(username));
+
+    if (version <= 0) {
+      return "sync.prefs." + encodedAccount;
+    } else {
+      final String sanitizedProduct = product.replace('.', '!').replace(' ', '!');
+      return "sync.prefs." + sanitizedProduct + "." + encodedAccount + "." + profile + "." + version;
+    }
+  }
+
+  public static void addToIndexBucketMap(TreeMap<Long, ArrayList<String>> map, long index, String value) {
+    ArrayList<String> bucket = map.get(index);
+    if (bucket == null) {
+      bucket = new ArrayList<String>();
+    }
+    bucket.add(value);
+    map.put(index, bucket);
+  }
+
+  /**
+   * Yes, an equality method that's null-safe.
+   */
+  private static boolean same(Object a, Object b) {
+    if (a == b) {
+      return true;
+    }
+    if (a == null || b == null) {
+      return false;      // If both null, case above applies.
+    }
+    return a.equals(b);
+  }
+
+  /**
+   * Return true if the two arrays are both null, or are both arrays
+   * containing the same elements in the same order.
+   */
+  public static boolean sameArrays(JSONArray a, JSONArray b) {
+    if (a == b) {
+      return true;
+    }
+    if (a == null || b == null) {
+      return false;
+    }
+    final int size = a.size();
+    if (size != b.size()) {
+      return false;
+    }
+    for (int i = 0; i < size; ++i) {
+      if (!same(a.get(i), b.get(i))) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  /**
+   * Takes a URI, extracting URI components.
+   * @param scheme the URI scheme on which to match.
+   */
+  @SuppressWarnings("deprecation")
+  public static Map<String, String> extractURIComponents(String scheme, String uri) {
+    if (uri.indexOf(scheme) != 0) {
+      throw new IllegalArgumentException("URI scheme does not match: " + scheme);
+    }
+
+    // Do this the hard way to avoid taking a large dependency on
+    // HttpClient or getting all regex-tastic.
+    String components = uri.substring(scheme.length());
+    HashMap<String, String> out = new HashMap<String, String>();
+    String[] parts = components.split("&");
+    for (int i = 0; i < parts.length; ++i) {
+      String part = parts[i];
+      if (part.length() == 0) {
+        continue;
+      }
+      String[] pair = part.split("=", 2);
+      switch (pair.length) {
+      case 0:
+        continue;
+      case 1:
+        out.put(URLDecoder.decode(pair[0]), null);
+        break;
+      case 2:
+        out.put(URLDecoder.decode(pair[0]), URLDecoder.decode(pair[1]));
+        break;
+      }
+    }
+    return out;
+  }
+
+  // Because TextUtils.join is not stubbed.
+  public static String toDelimitedString(String delimiter, Collection<? extends Object> items) {
+    if (items == null || items.size() == 0) {
+      return "";
+    }
+
+    StringBuilder sb = new StringBuilder();
+    int i = 0;
+    int c = items.size();
+    for (Object object : items) {
+      sb.append(object.toString());
+      if (++i < c) {
+        sb.append(delimiter);
+      }
+    }
+    return sb.toString();
+  }
+
+  public static String toCommaSeparatedString(Collection<? extends Object> items) {
+    return toDelimitedString(", ", items);
+  }
+
+  /**
+   * Names of stages to sync: (ALL intersect SYNC) intersect (ALL minus SKIP).
+   *
+   * @param knownStageNames collection of known stage names (set ALL above).
+   * @param toSync set SYNC above, or <code>null</code> to sync all known stages.
+   * @param toSkip set SKIP above, or <code>null</code> to not skip any stages.
+   * @return stage names.
+   */
+  public static Collection<String> getStagesToSync(final Collection<String> knownStageNames, Collection<String> toSync, Collection<String> toSkip) {
+    if (toSkip == null) {
+      toSkip = new HashSet<String>();
+    } else {
+      toSkip = new HashSet<String>(toSkip);
+    }
+
+    if (toSync == null) {
+      toSync = new HashSet<String>(knownStageNames);
+    } else {
+      toSync = new HashSet<String>(toSync);
+    }
+    toSync.retainAll(knownStageNames);
+    toSync.removeAll(toSkip);
+    return toSync;
+  }
+
+  /**
+   * Get names of stages to sync: (ALL intersect SYNC) intersect (ALL minus SKIP).
+   *
+   * @param knownStageNames collection of known stage names (set ALL above).
+   * @param extras
+   *          a <code>Bundle</code> instance (possibly null) optionally containing keys
+   *          <code>EXTRAS_KEY_STAGES_TO_SYNC</code> (set SYNC above) and
+   *          <code>EXTRAS_KEY_STAGES_TO_SKIP</code> (set SKIP above).
+   * @return stage names.
+   */
+  public static Collection<String> getStagesToSyncFromBundle(final Collection<String> knownStageNames, final Bundle extras) {
+    if (extras == null) {
+      return knownStageNames;
+    }
+    String toSyncString = extras.getString(Constants.EXTRAS_KEY_STAGES_TO_SYNC);
+    String toSkipString = extras.getString(Constants.EXTRAS_KEY_STAGES_TO_SKIP);
+    if (toSyncString == null && toSkipString == null) {
+      return knownStageNames;
+    }
+
+    ArrayList<String> toSync = null;
+    ArrayList<String> toSkip = null;
+    if (toSyncString != null) {
+      try {
+        toSync = new ArrayList<String>(new ExtendedJSONObject(toSyncString).keySet());
+      } catch (Exception e) {
+        Logger.warn(LOG_TAG, "Got exception parsing stages to sync: '" + toSyncString + "'.", e);
+      }
+    }
+    if (toSkipString != null) {
+      try {
+        toSkip = new ArrayList<String>(new ExtendedJSONObject(toSkipString).keySet());
+      } catch (Exception e) {
+        Logger.warn(LOG_TAG, "Got exception parsing stages to skip: '" + toSkipString + "'.", e);
+      }
+    }
+
+    Logger.info(LOG_TAG, "Asked to sync '" + Utils.toCommaSeparatedString(toSync) +
+                         "' and to skip '" + Utils.toCommaSeparatedString(toSkip) + "'.");
+    return getStagesToSync(knownStageNames, toSync, toSkip);
+  }
+
+  /**
+   * Put names of stages to sync and to skip into sync extras bundle.
+   *
+   * @param bundle
+   *          a <code>Bundle</code> instance (possibly null).
+   * @param stagesToSync
+   *          collection of stage names to sync: key
+   *          <code>EXTRAS_KEY_STAGES_TO_SYNC</code>; ignored if <code>null</code>.
+   * @param stagesToSkip
+   *          collection of stage names to skip: key
+   *          <code>EXTRAS_KEY_STAGES_TO_SKIP</code>; ignored if <code>null</code>.
+   */
+  public static void putStageNamesToSync(final Bundle bundle, final String[] stagesToSync, final String[] stagesToSkip) {
+    if (bundle == null) {
+      return;
+    }
+
+    if (stagesToSync != null) {
+      ExtendedJSONObject o = new ExtendedJSONObject();
+      for (String stageName : stagesToSync) {
+        o.put(stageName, 0);
+      }
+      bundle.putString(Constants.EXTRAS_KEY_STAGES_TO_SYNC, o.toJSONString());
+    }
+
+    if (stagesToSkip != null) {
+      ExtendedJSONObject o = new ExtendedJSONObject();
+      for (String stageName : stagesToSkip) {
+        o.put(stageName, 0);
+      }
+      bundle.putString(Constants.EXTRAS_KEY_STAGES_TO_SKIP, o.toJSONString());
+    }
+  }
+
+  /**
+   * Read contents of file as a string.
+   *
+   * @param context Android context.
+   * @param filename name of file to read; must not be null.
+   * @return <code>String</code> instance.
+   */
+  public static String readFile(final Context context, final String filename) {
+    if (filename == null) {
+      throw new IllegalArgumentException("Passed null filename in readFile.");
+    }
+
+    FileInputStream fis = null;
+    InputStreamReader isr = null;
+    BufferedReader br = null;
+
+    try {
+      fis = context.openFileInput(filename);
+      isr = new InputStreamReader(fis);
+      br = new BufferedReader(isr);
+      StringBuilder sb = new StringBuilder();
+      String line;
+      while ((line = br.readLine()) != null) {
+        sb.append(line);
+      }
+      return sb.toString();
+    } catch (Exception e) {
+      return null;
+    } finally {
+      if (isr != null) {
+        try {
+          isr.close();
+        } catch (IOException e) {
+          // Ignore.
+        }
+      }
+      if (fis != null) {
+        try {
+          fis.close();
+        } catch (IOException e) {
+          // Ignore.
+        }
+      }
+    }
+  }
+
+  /**
+   * Format a duration as a string, like "0.56 seconds".
+   *
+   * @param startMillis start time in milliseconds.
+   * @param endMillis end time in milliseconds.
+   * @return formatted string.
+   */
+  public static String formatDuration(long startMillis, long endMillis) {
+    final long duration = endMillis - startMillis;
+    return new DecimalFormat("#0.00 seconds").format(((double) duration) / 1000);
+  }
+
+  /**
+   * This will take a string containing a UTF-8 representation of a UTF-8
+   * byte array — e.g., "pïgéons1" — and return UTF-8 (e.g., "pïgéons1").
+   *
+   * This is the format produced by desktop Firefox when exchanging credentials
+   * containing non-ASCII characters.
+   */
+  public static String decodeUTF8(final String in) throws UnsupportedEncodingException {
+    final int length = in.length();
+    final byte[] asciiBytes = new byte[length];
+    for (int i = 0; i < length; ++i) {
+      asciiBytes[i] = (byte) in.codePointAt(i);
+    }
+    return new String(asciiBytes, "UTF-8");
+  }
+
+  /**
+   * Replace "foo@bar.com" with "XXX@XXX.XXX".
+   */
+  public static String obfuscateEmail(final String in) {
+    return in.replaceAll("[^@\\.]", "X");
+  }
+
+  public static void throwIfNull(Object... objects) {
+    for (Object object : objects) {
+      if (object == null) {
+        throw new IllegalArgumentException("object must not be null");
+      }
+    }
+  }
+
+  public static Executor newSynchronousExecutor() {
+    return new Executor() {
+      @Override
+      public void execute(Runnable runnable) {
+        runnable.run();
+      }
+    };
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/CryptoException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/CryptoException.java
new file mode 100644
index 000000000..a8d0483c9
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/CryptoException.java
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.crypto;
+
+import java.security.GeneralSecurityException;
+
+public class CryptoException extends Exception { 
+  public GeneralSecurityException cause;
+  public CryptoException(GeneralSecurityException e) {
+    this();
+    this.cause = e;
+  }
+  public CryptoException() {
+    
+  }
+  private static final long serialVersionUID = -5219310989960126830L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/CryptoInfo.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/CryptoInfo.java
new file mode 100644
index 000000000..355571c6a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/CryptoInfo.java
@@ -0,0 +1,232 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.crypto;
+
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.Mac;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+
+import org.mozilla.apache.commons.codec.binary.Base64;
+
+/*
+ * All info in these objects should be decoded (i.e. not BaseXX encoded).
+ */
+public class CryptoInfo {
+  private static final String TRANSFORMATION     = "AES/CBC/PKCS5Padding";
+  private static final String KEY_ALGORITHM_SPEC = "AES";
+
+  private byte[] message;
+  private byte[] iv;
+  private byte[] hmac;
+  private KeyBundle keys;
+
+  /**
+   * Return a CryptoInfo with given plaintext encrypted using given keys.
+   */
+  public static CryptoInfo encrypt(byte[] plaintextBytes, KeyBundle keys) throws CryptoException {
+    CryptoInfo info = new CryptoInfo(plaintextBytes, keys);
+    info.encrypt();
+    return info;
+  }
+
+  /**
+   * Return a CryptoInfo with given plaintext encrypted using given keys and initial vector.
+   */
+  public static CryptoInfo encrypt(byte[] plaintextBytes, byte[] iv, KeyBundle keys) throws CryptoException {
+    CryptoInfo info = new CryptoInfo(plaintextBytes, iv, null, keys);
+    info.encrypt();
+    return info;
+  }
+
+  /**
+   * Return a CryptoInfo with given ciphertext decrypted using given keys and initial vector, verifying that given HMAC validates.
+   */
+  public static CryptoInfo decrypt(byte[] ciphertext, byte[] iv, byte[] hmac, KeyBundle keys) throws CryptoException {
+    CryptoInfo info = new CryptoInfo(ciphertext, iv, hmac, keys);
+    info.decrypt();
+    return info;
+  }
+
+  /*
+   * Constructor typically used when encrypting.
+   */
+  public CryptoInfo(byte[] message, KeyBundle keys) {
+    this.setMessage(message);
+    this.setKeys(keys);
+  }
+
+  /*
+   * Constructor typically used when decrypting.
+   */
+  public CryptoInfo(byte[] message, byte[] iv, byte[] hmac, KeyBundle keys) {
+    this.setMessage(message);
+    this.setIV(iv);
+    this.setHMAC(hmac);
+    this.setKeys(keys);
+  }
+
+  public byte[] getMessage() {
+    return message;
+  }
+
+  public void setMessage(byte[] message) {
+    this.message = message;
+  }
+
+  public byte[] getIV() {
+    return iv;
+  }
+
+  public void setIV(byte[] iv) {
+    this.iv = iv;
+  }
+
+  public byte[] getHMAC() {
+    return hmac;
+  }
+
+  public void setHMAC(byte[] hmac) {
+    this.hmac = hmac;
+  }
+
+  public KeyBundle getKeys() {
+    return keys;
+  }
+
+  public void setKeys(KeyBundle keys) {
+    this.keys = keys;
+  }
+
+  /*
+   * Generate HMAC for given cipher text.
+   */
+  public static byte[] generatedHMACFor(byte[] message, KeyBundle keys) throws NoSuchAlgorithmException, InvalidKeyException {
+    Mac hmacHasher = HKDF.makeHMACHasher(keys.getHMACKey());
+    return hmacHasher.doFinal(Base64.encodeBase64(message));
+  }
+
+  /*
+   * Return true if generated HMAC is the same as the specified HMAC.
+   */
+  public boolean generatedHMACIsHMAC() throws NoSuchAlgorithmException, InvalidKeyException {
+    byte[] generatedHMAC = generatedHMACFor(getMessage(), getKeys());
+    byte[] expectedHMAC  = getHMAC();
+    return Arrays.equals(generatedHMAC, expectedHMAC);
+  }
+
+  /**
+   * Performs functionality common to both encryption and decryption.
+   *
+   * @param cipher
+   * @param inputMessage non-BaseXX-encoded message
+   * @return encrypted/decrypted message
+   * @throws CryptoException
+   */
+  private static byte[] commonCrypto(Cipher cipher, byte[] inputMessage)
+                        throws CryptoException {
+    byte[] outputMessage = null;
+    try {
+      outputMessage = cipher.doFinal(inputMessage);
+    } catch (IllegalBlockSizeException | BadPaddingException e) {
+      throw new CryptoException(e);
+    }
+      return outputMessage;
+  }
+
+  /**
+   * Encrypt a CryptoInfo in-place.
+   *
+   * @throws CryptoException
+   */
+  public void encrypt() throws CryptoException {
+
+    Cipher cipher = CryptoInfo.getCipher(TRANSFORMATION);
+    try {
+      byte[] encryptionKey = getKeys().getEncryptionKey();
+      SecretKeySpec spec = new SecretKeySpec(encryptionKey, KEY_ALGORITHM_SPEC);
+
+      // If no IV is provided, we allow the cipher to provide one.
+      if (getIV() == null || getIV().length == 0) {
+        cipher.init(Cipher.ENCRYPT_MODE, spec);
+      } else {
+        cipher.init(Cipher.ENCRYPT_MODE, spec, new IvParameterSpec(getIV()));
+      }
+    } catch (GeneralSecurityException ex) {
+      throw new CryptoException(ex);
+    }
+
+    // Encrypt.
+    byte[] encryptedBytes = commonCrypto(cipher, getMessage());
+    byte[] iv = cipher.getIV();
+
+    byte[] hmac;
+    // Generate HMAC.
+    try {
+      hmac = generatedHMACFor(encryptedBytes, keys);
+    } catch (NoSuchAlgorithmException | InvalidKeyException e) {
+      throw new CryptoException(e);
+    }
+
+    // Update in place.  keys is already set.
+    this.setHMAC(hmac);
+    this.setIV(iv);
+    this.setMessage(encryptedBytes);
+  }
+
+  /**
+   * Decrypt a CryptoInfo in-place.
+   *
+   * @throws CryptoException
+   */
+  public void decrypt() throws CryptoException {
+
+    // Check HMAC.
+    try {
+      if (!generatedHMACIsHMAC()) {
+        throw new HMACVerificationException();
+      }
+    } catch (NoSuchAlgorithmException | InvalidKeyException e) {
+      throw new CryptoException(e);
+    }
+
+    Cipher cipher = CryptoInfo.getCipher(TRANSFORMATION);
+    try {
+      byte[] encryptionKey = getKeys().getEncryptionKey();
+      SecretKeySpec spec = new SecretKeySpec(encryptionKey, KEY_ALGORITHM_SPEC);
+      cipher.init(Cipher.DECRYPT_MODE, spec, new IvParameterSpec(getIV()));
+    } catch (GeneralSecurityException ex) {
+      throw new CryptoException(ex);
+    }
+    byte[] decryptedBytes = commonCrypto(cipher, getMessage());
+    byte[] iv = cipher.getIV();
+
+    // Update in place.  keys is already set.
+    this.setHMAC(null);
+    this.setIV(iv);
+    this.setMessage(decryptedBytes);
+  }
+
+  /**
+   * Helper to get a Cipher object.
+   *
+   * @param transformation The type of Cipher to get.
+   */
+  private static Cipher getCipher(String transformation) throws CryptoException {
+    try {
+      return Cipher.getInstance(transformation);
+    } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
+      throw new CryptoException(e);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/HKDF.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/HKDF.java
new file mode 100644
index 000000000..16c0d8147
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/HKDF.java
@@ -0,0 +1,128 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.crypto;
+
+import java.security.InvalidKeyException;
+import java.security.Key;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+
+import org.mozilla.gecko.sync.Utils;
+
+/*
+ * A standards-compliant implementation of RFC 5869
+ * for HMAC-based Key Derivation Function.
+ * HMAC uses HMAC SHA256 standard.
+ */
+public class HKDF {
+  public static String HMAC_ALGORITHM = "hmacSHA256";
+
+  /**
+   * Used for conversion in cases in which you *know* the encoding exists.
+   */
+  public static final byte[] bytes(String in) {
+    try {
+      return in.getBytes("UTF-8");
+    } catch (java.io.UnsupportedEncodingException e) {
+      return null;
+    }
+  }
+
+  public static final int BLOCKSIZE     = 256 / 8;
+  public static final byte[] HMAC_INPUT = bytes("Sync-AES_256_CBC-HMAC256");
+
+  /*
+   * Step 1 of RFC 5869
+   * Get sha256HMAC Bytes
+   * Input: salt (message), IKM (input keyring material)
+   * Output: PRK (pseudorandom key)
+   */
+  public static byte[] hkdfExtract(byte[] salt, byte[] IKM) throws NoSuchAlgorithmException, InvalidKeyException {
+    return digestBytes(IKM, makeHMACHasher(salt));
+  }
+
+  /*
+   * Step 2 of RFC 5869.
+   * Input: PRK from step 1, info, length.
+   * Output: OKM (output keyring material).
+   */
+  public static byte[] hkdfExpand(byte[] prk, byte[] info, int len) throws NoSuchAlgorithmException, InvalidKeyException {
+    Mac hmacHasher = makeHMACHasher(prk);
+
+    byte[] T  = {};
+    byte[] Tn = {};
+
+    int iterations = (int) Math.ceil(((double)len) / (BLOCKSIZE));
+    for (int i = 0; i < iterations; i++) {
+      Tn = digestBytes(Utils.concatAll(Tn, info, Utils.hex2Byte(Integer.toHexString(i + 1))),
+                       hmacHasher);
+      T = Utils.concatAll(T, Tn);
+    }
+
+    byte[] result = new byte[len];
+    System.arraycopy(T, 0, result, 0, len);
+    return result;
+  }
+
+  /*
+   * Make HMAC key
+   * Input: key (salt)
+   * Output: Key HMAC-Key
+   */
+  public static Key makeHMACKey(byte[] key) {
+    if (key.length == 0) {
+      key = new byte[BLOCKSIZE];
+    }
+    return new SecretKeySpec(key, HMAC_ALGORITHM);
+  }
+
+  /*
+   * Make an HMAC hasher
+   * Input: Key hmacKey
+   * Ouput: An HMAC Hasher
+   */
+  public static Mac makeHMACHasher(byte[] key) throws NoSuchAlgorithmException, InvalidKeyException {
+    Mac hmacHasher = null;
+    hmacHasher = Mac.getInstance(HMAC_ALGORITHM);
+
+    // If Mac.getInstance doesn't throw NoSuchAlgorithmException, hmacHasher is
+    // non-null.
+    assert(hmacHasher != null);
+
+    hmacHasher.init(makeHMACKey(key));
+    return hmacHasher;
+  }
+
+  /*
+   * Hash bytes with given hasher
+   * Input: message to hash, HMAC hasher
+   * Output: hashed byte[].
+   */
+  public static byte[] digestBytes(byte[] message, Mac hasher) {
+    hasher.update(message);
+    byte[] ret = hasher.doFinal();
+    hasher.reset();
+    return ret;
+  }
+
+  public static byte[] derive(byte[] skm, byte[] xts, byte[] ctxInfo, int dkLen) throws InvalidKeyException, NoSuchAlgorithmException {
+    return hkdfExpand(hkdfExtract(xts, skm), ctxInfo, dkLen);
+  }
+
+  public static void deriveMany(byte[] skm, byte[] xts, byte[] ctxInfo, byte[]... keys) throws InvalidKeyException, NoSuchAlgorithmException {
+    int length = 0;
+    for (byte[] key : keys) {
+      length += key.length;
+    }
+    byte[] derived = hkdfExpand(hkdfExtract(xts, skm), ctxInfo, length);
+    int offset = 0;
+    for (byte[] key : keys) {
+      System.arraycopy(derived, offset, key, 0, key.length);
+      offset += key.length;
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/HMACVerificationException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/HMACVerificationException.java
new file mode 100644
index 000000000..f33babd52
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/HMACVerificationException.java
@@ -0,0 +1,12 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.crypto;
+
+public class HMACVerificationException extends CryptoException {
+  private static final long serialVersionUID = 1235311303567074897L;
+  public HMACVerificationException() {
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/KeyBundle.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/KeyBundle.java
new file mode 100644
index 000000000..2063b1e32
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/KeyBundle.java
@@ -0,0 +1,135 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.crypto;
+
+import java.io.UnsupportedEncodingException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+
+import javax.crypto.KeyGenerator;
+import javax.crypto.Mac;
+
+import org.mozilla.apache.commons.codec.binary.Base64;
+import org.mozilla.gecko.sync.Utils;
+
+public class KeyBundle {
+    private static final String KEY_ALGORITHM_SPEC = "AES";
+    private static final int    KEY_SIZE           = 256;
+
+    private byte[] encryptionKey;
+    private byte[] hmacKey;
+
+    // These are the same for every sync key bundle.
+    private static final byte[] EMPTY_BYTES      = {};
+    private static final byte[] ENCR_INPUT_BYTES = {1};
+    private static final byte[] HMAC_INPUT_BYTES = {2};
+
+    /*
+     * Mozilla's use of HKDF for getting keys from the Sync Key string.
+     *
+     * We do exactly 2 HKDF iterations and make the first iteration the
+     * encryption key and the second iteration the HMAC key.
+     *
+     */
+    public KeyBundle(String username, String base32SyncKey) throws CryptoException {
+      if (base32SyncKey == null) {
+        throw new IllegalArgumentException("No sync key provided.");
+      }
+      if (username == null || username.equals("")) {
+        throw new IllegalArgumentException("No username provided.");
+      }
+      // Hash appropriately.
+      try {
+        username = Utils.usernameFromAccount(username);
+      } catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
+        throw new IllegalArgumentException("Invalid username.");
+      }
+
+      byte[] syncKey = Utils.decodeFriendlyBase32(base32SyncKey);
+      byte[] user    = username.getBytes();
+
+      Mac hmacHasher;
+      try {
+        hmacHasher = HKDF.makeHMACHasher(syncKey);
+      } catch (NoSuchAlgorithmException | InvalidKeyException e) {
+        throw new CryptoException(e);
+      }
+      assert(hmacHasher != null); // If makeHMACHasher doesn't throw, then hmacHasher is non-null.
+
+      byte[] encrBytes = Utils.concatAll(EMPTY_BYTES, HKDF.HMAC_INPUT, user, ENCR_INPUT_BYTES);
+      byte[] encrKey   = HKDF.digestBytes(encrBytes, hmacHasher);
+      byte[] hmacBytes = Utils.concatAll(encrKey, HKDF.HMAC_INPUT, user, HMAC_INPUT_BYTES);
+
+      this.hmacKey       = HKDF.digestBytes(hmacBytes, hmacHasher);
+      this.encryptionKey = encrKey;
+    }
+
+    public KeyBundle(byte[] encryptionKey, byte[] hmacKey) {
+       this.setEncryptionKey(encryptionKey);
+       this.setHMACKey(hmacKey);
+    }
+
+    /**
+     * Make a KeyBundle with the specified base64-encoded keys.
+     *
+     * @return A KeyBundle with the specified keys.
+     */
+    public static KeyBundle fromBase64EncodedKeys(String base64EncryptionKey, String base64HmacKey) throws UnsupportedEncodingException {
+      return new KeyBundle(Base64.decodeBase64(base64EncryptionKey.getBytes("UTF-8")),
+                           Base64.decodeBase64(base64HmacKey.getBytes("UTF-8")));
+    }
+
+    /**
+     * Make a KeyBundle with two random 256 bit keys (encryption and HMAC).
+     *
+     * @return A KeyBundle with random keys.
+     */
+    public static KeyBundle withRandomKeys() throws CryptoException {
+      KeyGenerator keygen;
+      try {
+        keygen = KeyGenerator.getInstance(KEY_ALGORITHM_SPEC);
+      } catch (NoSuchAlgorithmException e) {
+        throw new CryptoException(e);
+      }
+
+      keygen.init(KEY_SIZE);
+      byte[] encryptionKey = keygen.generateKey().getEncoded();
+      byte[] hmacKey = keygen.generateKey().getEncoded();
+
+      return new KeyBundle(encryptionKey, hmacKey);
+    }
+
+    public byte[] getEncryptionKey() {
+        return encryptionKey;
+    }
+
+    public void setEncryptionKey(byte[] encryptionKey) {
+        this.encryptionKey = encryptionKey;
+    }
+
+    public byte[] getHMACKey() {
+        return hmacKey;
+    }
+
+    public void setHMACKey(byte[] hmacKey) {
+        this.hmacKey = hmacKey;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (!(o instanceof KeyBundle)) {
+        return false;
+      }
+      KeyBundle other = (KeyBundle) o;
+      return Arrays.equals(other.encryptionKey, this.encryptionKey) &&
+             Arrays.equals(other.hmacKey, this.hmacKey);
+    }
+
+    @Override
+    public int hashCode() {
+      throw new UnsupportedOperationException("No hashCode for KeyBundle.");
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/MissingCryptoInputException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/MissingCryptoInputException.java
new file mode 100644
index 000000000..8add1cf11
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/MissingCryptoInputException.java
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.crypto;
+
+public class MissingCryptoInputException extends CryptoException {
+  private static final long serialVersionUID = 5334412407012972445L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/NoKeyBundleException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/NoKeyBundleException.java
new file mode 100644
index 000000000..00e0f8b18
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/NoKeyBundleException.java
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.crypto;
+
+public class NoKeyBundleException extends CryptoException {
+  private static final long serialVersionUID = -6627154503154040915L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/PBKDF2.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/PBKDF2.java
new file mode 100644
index 000000000..636b2105c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/PBKDF2.java
@@ -0,0 +1,78 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.crypto;
+
+import java.security.GeneralSecurityException;
+import java.util.Arrays;
+
+import javax.crypto.Mac;
+import javax.crypto.ShortBufferException;
+import javax.crypto.spec.SecretKeySpec;
+
+public class PBKDF2 {
+  public static byte[] pbkdf2SHA256(byte[] password, byte[] salt, int c, int dkLen)
+      throws GeneralSecurityException {
+    final String algorithm = "HmacSHA256";
+    SecretKeySpec keyspec = new SecretKeySpec(password, algorithm);
+    Mac prf = Mac.getInstance(algorithm);
+    prf.init(keyspec);
+
+    int hLen = prf.getMacLength();
+
+    byte U_r[] = new byte[hLen];
+    byte U_i[] = new byte[salt.length + 4];
+    byte scratch[] = new byte[hLen];
+
+    int l = Math.max(dkLen, hLen);
+    int r = dkLen - (l - 1) * hLen;
+    byte T[] = new byte[l * hLen];
+    int ti_offset = 0;
+    for (int i = 1; i <= l; i++) {
+      Arrays.fill(U_r, (byte) 0);
+      F(T, ti_offset, prf, salt, c, i, U_r, U_i, scratch);
+      ti_offset += hLen;
+    }
+
+    if (r < hLen) {
+      // Incomplete last block.
+      byte DK[] = new byte[dkLen];
+      System.arraycopy(T, 0, DK, 0, dkLen);
+      return DK;
+    }
+
+    return T;
+  }
+
+  private static void F(byte[] dest, int offset, Mac prf, byte[] S, int c, int blockIndex, byte U_r[], byte U_i[], byte[] scratch)
+      throws ShortBufferException, IllegalStateException {
+    final int hLen = prf.getMacLength();
+
+    // U0 = S || INT (i);
+    System.arraycopy(S, 0, U_i, 0, S.length);
+    INT(U_i, S.length, blockIndex);
+
+    for (int i = 0; i < c; i++) {
+      prf.update(U_i);
+      prf.doFinal(scratch, 0);
+      U_i = scratch;
+      xor(U_r, U_i);
+    }
+
+    System.arraycopy(U_r, 0, dest, offset, hLen);
+  }
+
+  private static void xor(byte[] dest, byte[] src) {
+    for (int i = 0; i < dest.length; i++) {
+      dest[i] ^= src[i];
+    }
+  }
+
+  private static void INT(byte[] dest, int offset, int i) {
+    dest[offset + 0] = (byte) (i / (256 * 256 * 256));
+    dest[offset + 1] = (byte) (i / (256 * 256));
+    dest[offset + 2] = (byte) (i / (256));
+    dest[offset + 3] = (byte) (i);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/PersistedCrypto5Keys.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/PersistedCrypto5Keys.java
new file mode 100644
index 000000000..4dba4f258
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/crypto/PersistedCrypto5Keys.java
@@ -0,0 +1,103 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.crypto;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.CollectionKeys;
+import org.mozilla.gecko.sync.CryptoRecord;
+
+import android.content.SharedPreferences;
+
+public class PersistedCrypto5Keys {
+  public static final String LOG_TAG = "PersistedC5Keys";
+
+  public static final String CRYPTO5_KEYS_SERVER_RESPONSE_BODY = "crypto5KeysServerResponseBody";
+  public static final String CRYPTO5_KEYS_LAST_MODIFIED        = "crypto5KeysLastModified";
+
+  protected SharedPreferences prefs;
+  protected KeyBundle syncKeyBundle;
+
+  public PersistedCrypto5Keys(SharedPreferences prefs, KeyBundle syncKeyBundle) {
+    if (syncKeyBundle == null) {
+      throw new IllegalArgumentException("Null syncKeyBundle passed in to PersistedCrypto5Keys constructor.");
+    }
+    this.prefs = prefs;
+    this.syncKeyBundle = syncKeyBundle;
+  }
+
+  /**
+   * Get persisted crypto/keys.
+   * <p>
+   * crypto/keys is fetched from an encrypted JSON-encoded <code>CryptoRecord</code>.
+   *
+   * @return A <code>CollectionKeys</code> instance or <code>null</code> if none
+   *         is currently persisted.
+   */
+  public CollectionKeys keys() {
+    String keysJSON = prefs.getString(CRYPTO5_KEYS_SERVER_RESPONSE_BODY, null);
+    if (keysJSON == null) {
+      return null;
+    }
+    try {
+      CryptoRecord cryptoRecord = CryptoRecord.fromJSONRecord(keysJSON);
+      CollectionKeys keys = new CollectionKeys();
+      keys.setKeyPairsFromWBO(cryptoRecord, syncKeyBundle);
+      return keys;
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception decrypting persisted crypto/keys.", e);
+      return null;
+    }
+  }
+
+  /**
+   * Persist crypto/keys.
+   * <p>
+   * crypto/keys is stored as an encrypted JSON-encoded <code>CryptoRecord</code>.
+   *
+   * @param keys
+   *          The <code>CollectionKeys</code> object to persist, which should
+   *          have the same default key bundle as the sync key bundle.
+   */
+  public void persistKeys(CollectionKeys keys) {
+    if (keys == null) {
+      Logger.debug(LOG_TAG, "Clearing persisted crypto/keys.");
+      prefs.edit().remove(CRYPTO5_KEYS_SERVER_RESPONSE_BODY).commit();
+      return;
+    }
+    try {
+      CryptoRecord cryptoRecord = keys.asCryptoRecord();
+      cryptoRecord.keyBundle = syncKeyBundle;
+      cryptoRecord.encrypt();
+      String keysJSON = cryptoRecord.toJSONString();
+      Logger.debug(LOG_TAG, "Persisting crypto/keys.");
+      prefs.edit().putString(CRYPTO5_KEYS_SERVER_RESPONSE_BODY, keysJSON).commit();
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Got exception encrypting while persisting crypto/keys.", e);
+    }
+  }
+
+  public boolean persistedKeysExist() {
+    return lastModified() > 0;
+  }
+
+  public long lastModified() {
+    return prefs.getLong(CRYPTO5_KEYS_LAST_MODIFIED, -1);
+  }
+
+  public void persistLastModified(long lastModified) {
+    if (lastModified <= 0) {
+      Logger.debug(LOG_TAG, "Clearing persisted crypto/keys last modified timestamp.");
+      prefs.edit().remove(CRYPTO5_KEYS_LAST_MODIFIED).commit();
+      return;
+    }
+    Logger.debug(LOG_TAG, "Persisting crypto/keys last modified timestamp " + lastModified + ".");
+    prefs.edit().putLong(CRYPTO5_KEYS_LAST_MODIFIED, lastModified).commit();
+  }
+
+  public void purge() {
+    persistLastModified(-1);
+    persistKeys(null);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/ClientsDataDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/ClientsDataDelegate.java
new file mode 100644
index 000000000..07e9179f0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/ClientsDataDelegate.java
@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.delegates;
+
+public interface ClientsDataDelegate {
+  public String getAccountGUID();
+  public String getDefaultClientName();
+  public void setClientName(String clientName, long now);
+  public String getClientName();
+  public void setClientsCount(int clientsCount);
+  public int getClientsCount();
+  public boolean isLocalGUID(String guid);
+  public String getFormFactor();
+
+  /**
+   * The last time the client's data was modified in a way that should be
+   * reflected remotely.
+   * <p>
+   * Changing the client's name should be reflected remotely, while changing the
+   * clients count should not (since that data is only used to inform local
+   * policy.)
+   *
+   * @return timestamp in milliseconds.
+   */
+  public long getLastModifiedTimestamp();
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/FreshStartDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/FreshStartDelegate.java
new file mode 100644
index 000000000..2e5347061
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/FreshStartDelegate.java
@@ -0,0 +1,10 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.delegates;
+
+public interface FreshStartDelegate {
+  void onFreshStart();
+  void onFreshStartFailed(Exception e);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/GlobalSessionCallback.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/GlobalSessionCallback.java
new file mode 100644
index 000000000..9829f5b34
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/GlobalSessionCallback.java
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.delegates;
+
+import java.net.URI;
+
+import org.mozilla.gecko.sync.GlobalSession;
+import org.mozilla.gecko.sync.stage.GlobalSyncStage.Stage;
+
+public interface GlobalSessionCallback {
+  /**
+   * Request that no further syncs occur within the next `backoff` milliseconds.
+   * @param backoff a duration in milliseconds.
+   */
+  void requestBackoff(long backoff);
+
+  /**
+   * Called on a 401 HTTP response.
+   */
+  void informUnauthorizedResponse(GlobalSession globalSession, URI oldClusterURL);
+
+
+  /**
+   * Called when an HTTP failure indicates that a software upgrade is required.
+   */
+  void informUpgradeRequiredResponse(GlobalSession session);
+
+  /**
+   * Called when a migration sentinel has been found and processed successfully.
+   * <p>
+   * This account should stop syncing immediately, and arrange to delete itself.
+   */
+  void informMigrated(GlobalSession session);
+
+  void handleAborted(GlobalSession globalSession, String reason);
+  void handleError(GlobalSession globalSession, Exception ex);
+  void handleSuccess(GlobalSession globalSession);
+  void handleStageCompleted(Stage currentState, GlobalSession globalSession);
+
+  /**
+   * Called when a {@link GlobalSession} wants to know if it should continue
+   * to make storage requests.
+   *
+   * @return false if the session should make no further requests.
+   */
+  boolean shouldBackOffStorage();
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/JSONRecordFetchDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/JSONRecordFetchDelegate.java
new file mode 100644
index 000000000..90b73a33a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/JSONRecordFetchDelegate.java
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.delegates;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+/**
+ * A fairly generic delegate to handle fetches of single JSON object blobs, as
+ * provided by <code>info/configuration</code>, <code>info/collections</code>
+ * and <code>info/collection_counts</code>.
+ */
+public interface JSONRecordFetchDelegate {
+  public void handleSuccess(ExtendedJSONObject body);
+  public void handleFailure(SyncStorageResponse response);
+  public void handleError(Exception e);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/KeyUploadDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/KeyUploadDelegate.java
new file mode 100644
index 000000000..0cd5ec732
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/KeyUploadDelegate.java
@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.delegates;
+
+public interface KeyUploadDelegate {
+  /**
+   * Called when keys have been successfully uploaded to the server.
+   * <p>
+   * The uploaded keys are intentionally not exposed. It is possible for two
+   * clients to simultaneously upload keys and for each client to conclude that
+   * its keys are current (since the server returned 200 on upload). To shorten
+   * the window wherein two such clients can race, all clients should upload and
+   * then immediately re-download the fetched keys.
+   * <p>
+   * See Bug 692700, Bug 693893.
+   */
+  void onKeysUploaded();
+  void onKeyUploadFailed(Exception e);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/MetaGlobalDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/MetaGlobalDelegate.java
new file mode 100644
index 000000000..13854cb5a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/MetaGlobalDelegate.java
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.delegates;
+
+import org.mozilla.gecko.sync.MetaGlobal;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+public interface MetaGlobalDelegate {
+  public void handleSuccess(MetaGlobal global, SyncStorageResponse response);
+  public void handleMissing(MetaGlobal global, SyncStorageResponse response);
+  public void handleFailure(SyncStorageResponse response);
+  public void handleError(Exception e);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/WipeServerDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/WipeServerDelegate.java
new file mode 100644
index 000000000..ef3565812
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/delegates/WipeServerDelegate.java
@@ -0,0 +1,10 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.delegates;
+
+public interface WipeServerDelegate {
+  public void onWiped(long timestamp);
+  public void onWipeFailed(Exception e);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/Crypto5MiddlewareRepository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/Crypto5MiddlewareRepository.java
new file mode 100644
index 000000000..79319aff5
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/Crypto5MiddlewareRepository.java
@@ -0,0 +1,76 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.middleware;
+
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.repositories.IdentityRecordFactory;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCleanDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+
+import android.content.Context;
+
+/**
+ * Wrap an existing repository in middleware that encrypts and decrypts records
+ * passing through.
+ *
+ * @author rnewman
+ *
+ */
+public class Crypto5MiddlewareRepository extends MiddlewareRepository {
+
+  public RecordFactory recordFactory = new IdentityRecordFactory();
+
+  public class Crypto5MiddlewareRepositorySessionCreationDelegate extends MiddlewareRepository.SessionCreationDelegate {
+    private final Crypto5MiddlewareRepository repository;
+    private final RepositorySessionCreationDelegate outerDelegate;
+
+    public Crypto5MiddlewareRepositorySessionCreationDelegate(Crypto5MiddlewareRepository repository, RepositorySessionCreationDelegate outerDelegate) {
+      this.repository = repository;
+      this.outerDelegate = outerDelegate;
+    }
+
+    @Override
+    public void onSessionCreateFailed(Exception ex) {
+      this.outerDelegate.onSessionCreateFailed(ex);
+    }
+
+    @Override
+    public void onSessionCreated(RepositorySession session) {
+      // Do some work, then report success with the wrapping session.
+      Crypto5MiddlewareRepositorySession cryptoSession;
+      try {
+        // Synchronous, baby.
+        cryptoSession = new Crypto5MiddlewareRepositorySession(session, this.repository, recordFactory);
+      } catch (Exception ex) {
+        this.outerDelegate.onSessionCreateFailed(ex);
+        return;
+      }
+      this.outerDelegate.onSessionCreated(cryptoSession);
+    }
+  }
+
+  public KeyBundle keyBundle;
+  private final Repository inner;
+
+  public Crypto5MiddlewareRepository(Repository inner, KeyBundle keys) {
+    super();
+    this.inner = inner;
+    this.keyBundle = keys;
+  }
+  @Override
+  public void createSession(RepositorySessionCreationDelegate delegate, Context context) {
+    Crypto5MiddlewareRepositorySessionCreationDelegate delegateWrapper = new Crypto5MiddlewareRepositorySessionCreationDelegate(this, delegate);
+    inner.createSession(delegateWrapper, context);
+  }
+
+  @Override
+  public void clean(boolean success, RepositorySessionCleanDelegate delegate,
+                    Context context) {
+    this.inner.clean(success, delegate, context);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/Crypto5MiddlewareRepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/Crypto5MiddlewareRepositorySession.java
new file mode 100644
index 000000000..46de7a236
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/Crypto5MiddlewareRepositorySession.java
@@ -0,0 +1,172 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.middleware;
+
+import java.io.UnsupportedEncodingException;
+import java.util.concurrent.ExecutorService;
+
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.crypto.CryptoException;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.repositories.InactiveSessionException;
+import org.mozilla.gecko.sync.repositories.NoStoreDelegateException;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionStoreDelegate;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+/**
+ * It's a RepositorySession that accepts Records as input, producing CryptoRecords
+ * for submission to a remote service.
+ * Takes a RecordFactory as a parameter. This is in charge of taking decrypted CryptoRecords
+ * as input and producing some expected kind of Record as output for local use.
+ *
+ *
+
+
+
+                 +------------------------------------+
+                 |    Server11RepositorySession       |
+                 +-------------------------+----------+
+                           ^               |
+                           |               |
+                        Encrypted CryptoRecords
+                           |               |
+                           |               v
+                 +---------+--------------------------+
+                 | Crypto5MiddlewareRepositorySession |
+                 +------------------------------------+
+                           ^               |
+                           |               |  Decrypted CryptoRecords
+                           |               |
+                           |            +---------------+
+                           |            | RecordFactory |
+                           |            +--+------------+
+                           |               |
+                          Local Record instances
+                           |               |
+                           |               v
+                 +---------+--------------------------+
+                 |  Local RepositorySession instance  |
+                 +------------------------------------+
+
+
+ * @author rnewman
+ *
+ */
+public class Crypto5MiddlewareRepositorySession extends MiddlewareRepositorySession {
+  private final KeyBundle keyBundle;
+  private final RecordFactory recordFactory;
+
+  public Crypto5MiddlewareRepositorySession(RepositorySession session, Crypto5MiddlewareRepository repository, RecordFactory recordFactory) {
+    super(session, repository);
+    this.keyBundle = repository.keyBundle;
+    this.recordFactory = recordFactory;
+  }
+
+  public class DecryptingTransformingFetchDelegate implements RepositorySessionFetchRecordsDelegate {
+    private final RepositorySessionFetchRecordsDelegate next;
+    private final KeyBundle keyBundle;
+    private final RecordFactory recordFactory;
+
+    DecryptingTransformingFetchDelegate(RepositorySessionFetchRecordsDelegate next, KeyBundle bundle, RecordFactory recordFactory) {
+      this.next = next;
+      this.keyBundle = bundle;
+      this.recordFactory = recordFactory;
+    }
+
+    @Override
+    public void onFetchFailed(Exception ex, Record record) {
+      next.onFetchFailed(ex, record);
+    }
+
+    @Override
+    public void onFetchedRecord(Record record) {
+      CryptoRecord r;
+      try {
+        r = (CryptoRecord) record;
+      } catch (ClassCastException e) {
+        next.onFetchFailed(e, record);
+        return;
+      }
+      r.keyBundle = keyBundle;
+      try {
+        r.decrypt();
+      } catch (Exception e) {
+        next.onFetchFailed(e, r);
+        return;
+      }
+      Record transformed;
+      try {
+        transformed = this.recordFactory.createRecord(r);
+      } catch (Exception e) {
+        next.onFetchFailed(e, r);
+        return;
+      }
+      next.onFetchedRecord(transformed);
+    }
+
+    @Override
+    public void onFetchCompleted(final long fetchEnd) {
+      next.onFetchCompleted(fetchEnd);
+    }
+
+    @Override
+    public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor) {
+      // Synchronously perform *our* work, passing through appropriately.
+      RepositorySessionFetchRecordsDelegate deferredNext = next.deferredFetchDelegate(executor);
+      return new DecryptingTransformingFetchDelegate(deferredNext, keyBundle, recordFactory);
+    }
+  }
+
+  private DecryptingTransformingFetchDelegate makeUnwrappingDelegate(RepositorySessionFetchRecordsDelegate inner) {
+    if (inner == null) {
+      throw new IllegalArgumentException("Inner delegate cannot be null!");
+    }
+    return new DecryptingTransformingFetchDelegate(inner, this.keyBundle, this.recordFactory);
+  }
+
+  @Override
+  public void fetchSince(long timestamp,
+                         RepositorySessionFetchRecordsDelegate delegate) {
+    inner.fetchSince(timestamp, makeUnwrappingDelegate(delegate));
+  }
+
+  @Override
+  public void fetch(String[] guids,
+                    RepositorySessionFetchRecordsDelegate delegate) throws InactiveSessionException {
+    inner.fetch(guids, makeUnwrappingDelegate(delegate));
+  }
+
+  @Override
+  public void fetchAll(RepositorySessionFetchRecordsDelegate delegate) {
+    inner.fetchAll(makeUnwrappingDelegate(delegate));
+  }
+
+  @Override
+  public void setStoreDelegate(RepositorySessionStoreDelegate delegate) {
+    // TODO: it remains to be seen how this will work.
+    inner.setStoreDelegate(delegate);
+    this.delegate = delegate;             // So we can handle errors without involving inner.
+  }
+
+  @Override
+  public void store(Record record) throws NoStoreDelegateException {
+    if (delegate == null) {
+      throw new NoStoreDelegateException();
+    }
+    CryptoRecord rec = record.getEnvelope();
+    rec.keyBundle = this.keyBundle;
+    try {
+      rec.encrypt();
+    } catch (UnsupportedEncodingException | CryptoException e) {
+      delegate.onRecordStoreFailed(e, record.guid);
+      return;
+    }
+    // Allow the inner session to do delegate handling.
+    inner.store(rec);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/MiddlewareRepository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/MiddlewareRepository.java
new file mode 100644
index 000000000..d807aa5c0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/MiddlewareRepository.java
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.middleware;
+
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+
+public abstract class MiddlewareRepository extends Repository {
+
+  public abstract class SessionCreationDelegate implements
+      RepositorySessionCreationDelegate {
+
+    // We call through to our inner repository, so we don't need our own
+    // deferral scheme.
+    @Override
+    public RepositorySessionCreationDelegate deferredCreationDelegate() {
+      return this;
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/MiddlewareRepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/MiddlewareRepositorySession.java
new file mode 100644
index 000000000..e14ef5226
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/MiddlewareRepositorySession.java
@@ -0,0 +1,185 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.middleware;
+
+import java.util.concurrent.ExecutorService;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.InactiveSessionException;
+import org.mozilla.gecko.sync.repositories.InvalidSessionTransitionException;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+import org.mozilla.gecko.sync.repositories.RepositorySessionBundle;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionBeginDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionGuidsSinceDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionWipeDelegate;
+
+public abstract class MiddlewareRepositorySession extends RepositorySession {
+  private static final String LOG_TAG = "MiddlewareSession";
+  protected final RepositorySession inner;
+
+  public MiddlewareRepositorySession(RepositorySession innerSession, MiddlewareRepository repository) {
+    super(repository);
+    this.inner = innerSession;
+  }
+
+  @Override
+  public void wipe(RepositorySessionWipeDelegate delegate) {
+    inner.wipe(delegate);
+  }
+
+  public class MiddlewareRepositorySessionBeginDelegate implements RepositorySessionBeginDelegate {
+
+    private final MiddlewareRepositorySession outerSession;
+    private final RepositorySessionBeginDelegate next;
+
+    public MiddlewareRepositorySessionBeginDelegate(MiddlewareRepositorySession outerSession, RepositorySessionBeginDelegate next) {
+      this.outerSession = outerSession;
+      this.next = next;
+    }
+
+    @Override
+    public void onBeginFailed(Exception ex) {
+      next.onBeginFailed(ex);
+    }
+
+    @Override
+    public void onBeginSucceeded(RepositorySession session) {
+      next.onBeginSucceeded(outerSession);
+    }
+
+    @Override
+    public RepositorySessionBeginDelegate deferredBeginDelegate(ExecutorService executor) {
+      final RepositorySessionBeginDelegate deferred = next.deferredBeginDelegate(executor);
+      return new RepositorySessionBeginDelegate() {
+        @Override
+        public void onBeginSucceeded(RepositorySession session) {
+          if (inner != session) {
+            Logger.warn(LOG_TAG, "Got onBeginSucceeded for session " + session + ", not our inner session!");
+          }
+          deferred.onBeginSucceeded(outerSession);
+        }
+
+        @Override
+        public void onBeginFailed(Exception ex) {
+          deferred.onBeginFailed(ex);
+        }
+
+        @Override
+        public RepositorySessionBeginDelegate deferredBeginDelegate(ExecutorService executor) {
+          return this;
+        }
+      };
+    }
+  }
+
+  @Override
+  public void begin(RepositorySessionBeginDelegate delegate) throws InvalidSessionTransitionException {
+    inner.begin(new MiddlewareRepositorySessionBeginDelegate(this, delegate));
+  }
+
+  public class MiddlewareRepositorySessionFinishDelegate implements RepositorySessionFinishDelegate {
+    private final MiddlewareRepositorySession outerSession;
+    private final RepositorySessionFinishDelegate next;
+
+    public MiddlewareRepositorySessionFinishDelegate(MiddlewareRepositorySession outerSession, RepositorySessionFinishDelegate next) {
+      this.outerSession = outerSession;
+      this.next = next;
+    }
+
+    @Override
+    public void onFinishFailed(Exception ex) {
+      next.onFinishFailed(ex);
+    }
+
+    @Override
+    public void onFinishSucceeded(RepositorySession session, RepositorySessionBundle bundle) {
+      next.onFinishSucceeded(outerSession, bundle);
+    }
+
+    @Override
+    public RepositorySessionFinishDelegate deferredFinishDelegate(ExecutorService executor) {
+      return this;
+    }
+  }
+
+  @Override
+  public void finish(RepositorySessionFinishDelegate delegate) throws InactiveSessionException {
+    inner.finish(new MiddlewareRepositorySessionFinishDelegate(this, delegate));
+  }
+
+
+  @Override
+  public synchronized void ensureActive() throws InactiveSessionException {
+    inner.ensureActive();
+  }
+
+  @Override
+  public synchronized boolean isActive() {
+    return inner.isActive();
+  }
+
+  @Override
+  public synchronized SessionStatus getStatus() {
+    return inner.getStatus();
+  }
+
+  @Override
+  public synchronized void setStatus(SessionStatus status) {
+    inner.setStatus(status);
+  }
+
+  @Override
+  public synchronized void transitionFrom(SessionStatus from, SessionStatus to)
+      throws InvalidSessionTransitionException {
+    inner.transitionFrom(from, to);
+  }
+
+  @Override
+  public void abort() {
+    inner.abort();
+  }
+
+  @Override
+  public void abort(RepositorySessionFinishDelegate delegate) {
+    inner.abort(new MiddlewareRepositorySessionFinishDelegate(this, delegate));
+  }
+
+  @Override
+  public void guidsSince(long timestamp, RepositorySessionGuidsSinceDelegate delegate) {
+    // TODO: need to do anything here?
+    inner.guidsSince(timestamp, delegate);
+  }
+
+  @Override
+  public void storeDone() {
+    inner.storeDone();
+  }
+
+  @Override
+  public void storeDone(long storeEnd) {
+    inner.storeDone(storeEnd);
+  }
+
+  @Override
+  public boolean shouldSkip() {
+    return inner.shouldSkip();
+  }
+
+  @Override
+  public boolean dataAvailable() {
+    return inner.dataAvailable();
+  }
+
+  @Override
+  public void unbundle(RepositorySessionBundle bundle) {
+    inner.unbundle(bundle);
+  }
+
+  @Override
+  public long getLastSyncTimestamp() {
+    return inner.getLastSyncTimestamp();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/AbstractBearerTokenAuthHeaderProvider.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/AbstractBearerTokenAuthHeaderProvider.java
new file mode 100644
index 000000000..e3b4f25b1
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/AbstractBearerTokenAuthHeaderProvider.java
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+import ch.boye.httpclientandroidlib.message.BasicHeader;
+import ch.boye.httpclientandroidlib.protocol.BasicHttpContext;
+
+/**
+ * An <code>AuthHeaderProvider</code> that returns an Authorization header for
+ * bearer tokens, adding a simple prefix.
+ */
+public abstract class AbstractBearerTokenAuthHeaderProvider implements AuthHeaderProvider {
+  protected final String header;
+
+  public AbstractBearerTokenAuthHeaderProvider(String token) {
+    if (token == null) {
+      throw new IllegalArgumentException("token must not be null.");
+    }
+
+    this.header = getPrefix() + " " + token;
+  }
+
+  protected abstract String getPrefix();
+
+  @Override
+  public Header getAuthHeader(HttpRequestBase request, BasicHttpContext context, DefaultHttpClient client) {
+    return new BasicHeader("Authorization", header);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/AuthHeaderProvider.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/AuthHeaderProvider.java
new file mode 100644
index 000000000..7be6fef3d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/AuthHeaderProvider.java
@@ -0,0 +1,30 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.security.GeneralSecurityException;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+import ch.boye.httpclientandroidlib.protocol.BasicHttpContext;
+
+/**
+ * An <code>AuthHeaderProvider</code> generates HTTP Authorization headers for
+ * HTTP requests.
+ */
+public interface AuthHeaderProvider {
+  /**
+   * Generate an HTTP Authorization header.
+   *
+   * @param request HTTP request.
+   * @param context HTTP context.
+   * @param client HTTP client.
+   * @return HTTP Authorization header.
+   * @throws GeneralSecurityException usually wrapping a more specific exception.
+   */
+  Header getAuthHeader(HttpRequestBase request, BasicHttpContext context, DefaultHttpClient client)
+    throws GeneralSecurityException;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BaseResource.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BaseResource.java
new file mode 100644
index 000000000..60bbc86bb
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BaseResource.java
@@ -0,0 +1,565 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.lang.ref.WeakReference;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.security.GeneralSecurityException;
+import java.security.KeyManagementException;
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import javax.net.ssl.SSLContext;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.background.common.GlobalConstants;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.HttpEntity;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.HttpVersion;
+import ch.boye.httpclientandroidlib.client.AuthCache;
+import ch.boye.httpclientandroidlib.client.ClientProtocolException;
+import ch.boye.httpclientandroidlib.client.entity.GzipCompressingEntity;
+import ch.boye.httpclientandroidlib.client.methods.HttpDelete;
+import ch.boye.httpclientandroidlib.client.methods.HttpGet;
+import ch.boye.httpclientandroidlib.client.methods.HttpPatch;
+import ch.boye.httpclientandroidlib.client.methods.HttpPost;
+import ch.boye.httpclientandroidlib.client.methods.HttpPut;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.client.methods.HttpUriRequest;
+import ch.boye.httpclientandroidlib.client.protocol.ClientContext;
+import ch.boye.httpclientandroidlib.conn.ClientConnectionManager;
+import ch.boye.httpclientandroidlib.conn.scheme.PlainSocketFactory;
+import ch.boye.httpclientandroidlib.conn.scheme.Scheme;
+import ch.boye.httpclientandroidlib.conn.scheme.SchemeRegistry;
+import ch.boye.httpclientandroidlib.conn.ssl.SSLSocketFactory;
+import ch.boye.httpclientandroidlib.entity.StringEntity;
+import ch.boye.httpclientandroidlib.impl.client.BasicAuthCache;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+import ch.boye.httpclientandroidlib.impl.conn.tsccm.ThreadSafeClientConnManager;
+import ch.boye.httpclientandroidlib.params.HttpConnectionParams;
+import ch.boye.httpclientandroidlib.params.HttpParams;
+import ch.boye.httpclientandroidlib.params.HttpProtocolParams;
+import ch.boye.httpclientandroidlib.protocol.BasicHttpContext;
+import ch.boye.httpclientandroidlib.protocol.HttpContext;
+import ch.boye.httpclientandroidlib.util.EntityUtils;
+
+/**
+ * Provide simple HTTP access to a Sync server or similar.
+ * Implements Basic Auth by asking its delegate for credentials.
+ * Communicates with a ResourceDelegate to asynchronously return responses and errors.
+ * Exposes simple get/post/put/delete methods.
+ */
+@SuppressWarnings("deprecation")
+public class BaseResource implements Resource {
+  private static final String ANDROID_LOOPBACK_IP = "10.0.2.2";
+
+  private static final int MAX_TOTAL_CONNECTIONS     = 20;
+  private static final int MAX_CONNECTIONS_PER_ROUTE = 10;
+
+  private boolean retryOnFailedRequest = true;
+
+  public static boolean rewriteLocalhost = true;
+
+  private static final String LOG_TAG = "BaseResource";
+
+  protected final URI uri;
+  protected BasicHttpContext context;
+  protected DefaultHttpClient client;
+  public    ResourceDelegate delegate;
+  protected HttpRequestBase request;
+  public final String charset = "utf-8";
+
+  private boolean shouldGzipCompress = false;
+  // A hint whether uploaded payloads are chunked. Default true to use GzipCompressingEntity, which is built-in functionality.
+  private boolean shouldChunkUploadsHint = true;
+
+  /**
+   * We have very few writes (observers tend to be installed around sync
+   * sessions) and many iterations (every HTTP request iterates observers), so
+   * CopyOnWriteArrayList is a reasonable choice.
+   */
+  protected static final CopyOnWriteArrayList<WeakReference<HttpResponseObserver>>
+    httpResponseObservers = new CopyOnWriteArrayList<>();
+
+  public BaseResource(String uri) throws URISyntaxException {
+    this(uri, rewriteLocalhost);
+  }
+
+  public BaseResource(URI uri) {
+    this(uri, rewriteLocalhost);
+  }
+
+  public BaseResource(String uri, boolean rewrite) throws URISyntaxException {
+    this(new URI(uri), rewrite);
+  }
+
+  public BaseResource(URI uri, boolean rewrite) {
+    if (uri == null) {
+      throw new IllegalArgumentException("uri must not be null");
+    }
+    if (rewrite && "localhost".equals(uri.getHost())) {
+      // Rewrite localhost URIs to refer to the special Android emulator loopback passthrough interface.
+      Logger.debug(LOG_TAG, "Rewriting " + uri + " to point to " + ANDROID_LOOPBACK_IP + ".");
+      try {
+        this.uri = new URI(uri.getScheme(), uri.getUserInfo(), ANDROID_LOOPBACK_IP, uri.getPort(), uri.getPath(), uri.getQuery(), uri.getFragment());
+      } catch (URISyntaxException e) {
+        Logger.error(LOG_TAG, "Got error rewriting URI for Android emulator.", e);
+        throw new IllegalArgumentException("Invalid URI", e);
+      }
+    } else {
+      this.uri = uri;
+    }
+  }
+
+  public static void addHttpResponseObserver(HttpResponseObserver newHttpResponseObserver) {
+    if (newHttpResponseObserver == null) {
+      return;
+    }
+    httpResponseObservers.add(new WeakReference<HttpResponseObserver>(newHttpResponseObserver));
+  }
+
+  public static boolean isHttpResponseObserver(HttpResponseObserver httpResponseObserver) {
+    for (WeakReference<HttpResponseObserver> weakReference : httpResponseObservers) {
+      HttpResponseObserver innerHttpResponseObserver = weakReference.get();
+      if (innerHttpResponseObserver == httpResponseObserver) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  public static boolean removeHttpResponseObserver(HttpResponseObserver httpResponseObserver) {
+    for (WeakReference<HttpResponseObserver> weakReference : httpResponseObservers) {
+      HttpResponseObserver innerHttpResponseObserver = weakReference.get();
+      if (innerHttpResponseObserver == httpResponseObserver) {
+        // It's safe to mutate the observers while iterating.
+        httpResponseObservers.remove(weakReference);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  @Override
+  public URI getURI() {
+    return this.uri;
+  }
+
+  @Override
+  public String getURIString() {
+    return this.uri.toString();
+  }
+
+  @Override
+  public String getHostname() {
+    return this.getURI().getHost();
+  }
+
+  /**
+   * Causes the Resource to compress the uploaded entity payload in requests with payloads (e.g. post, put)
+   * @param shouldCompress true if the entity should be compressed, false otherwise
+   */
+  public void setShouldCompressUploadedEntity(final boolean shouldCompress) {
+    shouldGzipCompress = shouldCompress;
+  }
+
+  /**
+   * Causes the Resource to chunk the uploaded entity payload in requests with payloads (e.g. post, put).
+   * Note: this flag is only a hint - chunking is not guaranteed.
+   *
+   * Chunking is currently supported with gzip compression.
+   *
+   * @param shouldChunk true if the transfer should be chunked, false otherwise
+   */
+  public void setShouldChunkUploadsHint(final boolean shouldChunk) {
+    shouldChunkUploadsHint = shouldChunk;
+  }
+
+  private HttpEntity getMaybeCompressedEntity(final HttpEntity entity) {
+    if (!shouldGzipCompress) {
+      return entity;
+    }
+
+    return shouldChunkUploadsHint ? new GzipCompressingEntity(entity) : new GzipNonChunkedCompressingEntity(entity);
+  }
+
+  /**
+   * This shuts up HttpClient, which will otherwise debug log about there
+   * being no auth cache in the context.
+   */
+  private static void addAuthCacheToContext(HttpUriRequest request, HttpContext context) {
+    AuthCache authCache = new BasicAuthCache();                // Not thread safe.
+    context.setAttribute(ClientContext.AUTH_CACHE, authCache);
+  }
+
+  /**
+   * Invoke this after delegate and request have been set.
+   * @throws NoSuchAlgorithmException
+   * @throws KeyManagementException
+   */
+  protected void prepareClient() throws KeyManagementException, NoSuchAlgorithmException, GeneralSecurityException {
+    context = new BasicHttpContext();
+
+    // We could reuse these client instances, except that we mess around
+    // with their parameters… so we'd need a pool of some kind.
+    client = new DefaultHttpClient(getConnectionManager());
+
+    // TODO: Eventually we should use Apache HttpAsyncClient. It's not out of alpha yet.
+    // Until then, we synchronously make the request, then invoke our delegate's callback.
+    AuthHeaderProvider authHeaderProvider = delegate.getAuthHeaderProvider();
+    if (authHeaderProvider != null) {
+      Header authHeader = authHeaderProvider.getAuthHeader(request, context, client);
+      if (authHeader != null) {
+        request.addHeader(authHeader);
+        Logger.debug(LOG_TAG, "Added auth header.");
+      }
+    }
+
+    addAuthCacheToContext(request, context);
+
+    HttpParams params = client.getParams();
+    HttpConnectionParams.setConnectionTimeout(params, delegate.connectionTimeout());
+    HttpConnectionParams.setSoTimeout(params, delegate.socketTimeout());
+    HttpConnectionParams.setStaleCheckingEnabled(params, false);
+    HttpProtocolParams.setContentCharset(params, charset);
+    HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
+    final String userAgent = delegate.getUserAgent();
+    if (userAgent != null) {
+      HttpProtocolParams.setUserAgent(params, userAgent);
+    }
+    delegate.addHeaders(request, client);
+  }
+
+  private static final Object connManagerMonitor = new Object();
+  private static ClientConnectionManager connManager;
+
+  // Call within a synchronized block on connManagerMonitor.
+  private static ClientConnectionManager enableTLSConnectionManager() throws KeyManagementException, NoSuchAlgorithmException  {
+    SSLContext sslContext = SSLContext.getInstance("TLS");
+    sslContext.init(null, null, new SecureRandom());
+
+    Logger.debug(LOG_TAG, "Using protocols and cipher suites for Android API " + android.os.Build.VERSION.SDK_INT);
+    SSLSocketFactory sf = new SSLSocketFactory(sslContext, GlobalConstants.DEFAULT_PROTOCOLS, GlobalConstants.DEFAULT_CIPHER_SUITES, null);
+    SchemeRegistry schemeRegistry = new SchemeRegistry();
+    schemeRegistry.register(new Scheme("https", 443, sf));
+    schemeRegistry.register(new Scheme("http", 80, new PlainSocketFactory()));
+    ThreadSafeClientConnManager cm = new ThreadSafeClientConnManager(schemeRegistry);
+
+    cm.setMaxTotal(MAX_TOTAL_CONNECTIONS);
+    cm.setDefaultMaxPerRoute(MAX_CONNECTIONS_PER_ROUTE);
+    connManager = cm;
+    return cm;
+  }
+
+  public static ClientConnectionManager getConnectionManager() throws KeyManagementException, NoSuchAlgorithmException
+                                                         {
+    // TODO: shutdown.
+    synchronized (connManagerMonitor) {
+      if (connManager != null) {
+        return connManager;
+      }
+      return enableTLSConnectionManager();
+    }
+  }
+
+  /**
+   * Do some cleanup, so we don't need the stale connection check.
+   */
+  public static void closeExpiredConnections() {
+    ClientConnectionManager connectionManager;
+    synchronized (connManagerMonitor) {
+      connectionManager = connManager;
+    }
+    if (connectionManager == null) {
+      return;
+    }
+    Logger.trace(LOG_TAG, "Closing expired connections.");
+    connectionManager.closeExpiredConnections();
+  }
+
+  public static void shutdownConnectionManager() {
+    ClientConnectionManager connectionManager;
+    synchronized (connManagerMonitor) {
+      connectionManager = connManager;
+      connManager = null;
+    }
+    if (connectionManager == null) {
+      return;
+    }
+    Logger.debug(LOG_TAG, "Shutting down connection manager.");
+    connectionManager.shutdown();
+  }
+
+  private void execute() {
+    HttpResponse response;
+    try {
+      response = client.execute(request, context);
+      Logger.debug(LOG_TAG, "Response: " + response.getStatusLine().toString());
+    } catch (ClientProtocolException e) {
+      delegate.handleHttpProtocolException(e);
+      return;
+    } catch (IOException e) {
+      Logger.debug(LOG_TAG, "I/O exception returned from execute.");
+      if (!retryOnFailedRequest) {
+        delegate.handleHttpIOException(e);
+      } else {
+        retryRequest();
+      }
+      return;
+    } catch (Exception e) {
+      // Bug 740731: Don't let an exception fall through. Wrapping isn't
+      // optimal, but often the exception is treated as an Exception anyway.
+      if (!retryOnFailedRequest) {
+        // Bug 769671: IOException(Throwable cause) was added only in API level 9.
+        final IOException ex = new IOException();
+        ex.initCause(e);
+        delegate.handleHttpIOException(ex);
+      } else {
+        retryRequest();
+      }
+      return;
+    }
+
+    // Don't retry if the observer or delegate throws!
+    for (WeakReference<HttpResponseObserver> weakReference : httpResponseObservers) {
+      HttpResponseObserver observer = weakReference.get();
+      if (observer != null) {
+        observer.observeHttpResponse(request, response);
+      }
+    }
+    delegate.handleHttpResponse(response);
+  }
+
+  private void retryRequest() {
+    // Only retry once.
+    retryOnFailedRequest = false;
+    Logger.debug(LOG_TAG, "Retrying request...");
+    this.execute();
+  }
+
+  private void go(HttpRequestBase request) {
+   if (delegate == null) {
+      throw new IllegalArgumentException("No delegate provided.");
+    }
+    this.request = request;
+    try {
+      this.prepareClient();
+    } catch (KeyManagementException e) {
+      Logger.error(LOG_TAG, "Couldn't prepare client.", e);
+      delegate.handleTransportException(e);
+      return;
+    } catch (GeneralSecurityException e) {
+      Logger.error(LOG_TAG, "Couldn't prepare client.", e);
+      delegate.handleTransportException(e);
+      return;
+    } catch (Exception e) {
+      // Bug 740731: Don't let an exception fall through. Wrapping isn't
+      // optimal, but often the exception is treated as an Exception anyway.
+      delegate.handleTransportException(new GeneralSecurityException(e));
+      return;
+    }
+    this.execute();
+  }
+
+  @Override
+  public void get() {
+    Logger.debug(LOG_TAG, "HTTP GET " + this.uri.toASCIIString());
+    this.go(new HttpGet(this.uri));
+  }
+
+  /**
+   * Perform an HTTP GET as with {@link BaseResource#get()}, returning only
+   * after callbacks have been invoked.
+   */
+  public void getBlocking() {
+    // Until we use the asynchronous Apache HttpClient, we can simply call
+    // through.
+    this.get();
+  }
+
+  @Override
+  public void delete() {
+    Logger.debug(LOG_TAG, "HTTP DELETE " + this.uri.toASCIIString());
+    this.go(new HttpDelete(this.uri));
+  }
+
+  @Override
+  public void post(HttpEntity body) {
+    Logger.debug(LOG_TAG, "HTTP POST " + this.uri.toASCIIString());
+    body = getMaybeCompressedEntity(body);
+    HttpPost request = new HttpPost(this.uri);
+    request.setEntity(body);
+    this.go(request);
+  }
+
+  @Override
+  public void patch(HttpEntity body) {
+    Logger.debug(LOG_TAG, "HTTP PATCH " + this.uri.toASCIIString());
+    body = getMaybeCompressedEntity(body);
+    HttpPatch request = new HttpPatch(this.uri);
+    request.setEntity(body);
+    this.go(request);
+  }
+
+  @Override
+  public void put(HttpEntity body) {
+    Logger.debug(LOG_TAG, "HTTP PUT " + this.uri.toASCIIString());
+    body = getMaybeCompressedEntity(body);
+    HttpPut request = new HttpPut(this.uri);
+    request.setEntity(body);
+    this.go(request);
+  }
+
+  protected static StringEntity stringEntityWithContentTypeApplicationJSON(String s) {
+    StringEntity e = new StringEntity(s, "UTF-8");
+    e.setContentType("application/json");
+    return e;
+  }
+
+  /**
+   * Helper for turning a JSON object into a payload.
+   * @throws UnsupportedEncodingException
+   */
+  protected static StringEntity jsonEntity(JSONObject body) {
+    return stringEntityWithContentTypeApplicationJSON(body.toJSONString());
+  }
+
+  /**
+   * Helper for turning an extended JSON object into a payload.
+   * @throws UnsupportedEncodingException
+   */
+  protected static StringEntity jsonEntity(ExtendedJSONObject body) {
+    return stringEntityWithContentTypeApplicationJSON(body.toJSONString());
+  }
+
+  /**
+   * Helper for turning a JSON array into a payload.
+   * @throws UnsupportedEncodingException
+   */
+  protected static HttpEntity jsonEntity(JSONArray toPOST) throws UnsupportedEncodingException {
+    return stringEntityWithContentTypeApplicationJSON(toPOST.toJSONString());
+  }
+
+  /**
+   * Best-effort attempt to ensure that the entity has been fully consumed and
+   * that the underlying stream has been closed.
+   *
+   * This releases the connection back to the connection pool.
+   *
+   * @param entity The HttpEntity to be consumed.
+   */
+  public static void consumeEntity(HttpEntity entity) {
+    try {
+      EntityUtils.consume(entity);
+    } catch (IOException e) {
+      // Doesn't matter.
+    }
+  }
+
+  /**
+   * Best-effort attempt to ensure that the entity corresponding to the given
+   * HTTP response has been fully consumed and that the underlying stream has
+   * been closed.
+   *
+   * This releases the connection back to the connection pool.
+   *
+   * @param response
+   *          The HttpResponse to be consumed.
+   */
+  public static void consumeEntity(HttpResponse response) {
+    if (response == null) {
+      return;
+    }
+    try {
+      EntityUtils.consume(response.getEntity());
+    } catch (IOException e) {
+    }
+  }
+
+  /**
+   * Best-effort attempt to ensure that the entity corresponding to the given
+   * Sync storage response has been fully consumed and that the underlying
+   * stream has been closed.
+   *
+   * This releases the connection back to the connection pool.
+   *
+   * @param response
+   *          The SyncStorageResponse to be consumed.
+   */
+  public static void consumeEntity(SyncStorageResponse response) {
+    if (response.httpResponse() == null) {
+      return;
+    }
+    consumeEntity(response.httpResponse());
+  }
+
+  /**
+   * Best-effort attempt to ensure that the reader has been fully consumed, so
+   * that the underlying stream will be closed.
+   *
+   * This should allow the connection to be released back to the connection pool.
+   *
+   * @param reader The BufferedReader to be consumed.
+   */
+  public static void consumeReader(BufferedReader reader) {
+    try {
+      reader.close();
+    } catch (IOException e) {
+      // Do nothing.
+    }
+  }
+
+  public void post(JSONArray jsonArray) throws UnsupportedEncodingException {
+    post(jsonEntity(jsonArray));
+  }
+
+  public void put(JSONObject jsonObject) throws UnsupportedEncodingException {
+    put(jsonEntity(jsonObject));
+  }
+
+  public void put(ExtendedJSONObject o) {
+    put(jsonEntity(o));
+  }
+
+  public void post(ExtendedJSONObject o) {
+    post(jsonEntity(o));
+  }
+
+  /**
+   * Perform an HTTP POST as with {@link BaseResource#post(ExtendedJSONObject)}, returning only
+   * after callbacks have been invoked.
+   */
+  public void postBlocking(final ExtendedJSONObject o) {
+    // Until we use the asynchronous Apache HttpClient, we can simply call
+    // through.
+    post(jsonEntity(o));
+  }
+
+  public void post(JSONObject jsonObject) throws UnsupportedEncodingException {
+    post(jsonEntity(jsonObject));
+  }
+
+  public void patch(JSONArray jsonArray) throws UnsupportedEncodingException {
+    patch(jsonEntity(jsonArray));
+  }
+
+  public void patch(ExtendedJSONObject o) {
+    patch(jsonEntity(o));
+  }
+
+  public void patch(JSONObject jsonObject) throws UnsupportedEncodingException {
+    patch(jsonEntity(jsonObject));
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BaseResourceDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BaseResourceDelegate.java
new file mode 100644
index 000000000..84ae7a3d5
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BaseResourceDelegate.java
@@ -0,0 +1,44 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+
+/**
+ * Shared abstract class for resource delegate that use the same timeouts
+ * and no credentials.
+ *
+ * @author rnewman
+ *
+ */
+public abstract class BaseResourceDelegate implements ResourceDelegate {
+  public static int connectionTimeoutInMillis = 1000 * 30;     // Wait 30s for a connection to open.
+  public static int socketTimeoutInMillis     = 1000 * 2 * 60; // Wait 2 minutes for data.
+
+  protected Resource resource;
+  public BaseResourceDelegate(Resource resource) {
+    this.resource = resource;
+  }
+
+  @Override
+  public int connectionTimeout() {
+    return connectionTimeoutInMillis;
+  }
+
+  @Override
+  public int socketTimeout() {
+    return socketTimeoutInMillis;
+  }
+
+  @Override
+  public AuthHeaderProvider getAuthHeaderProvider() {
+    return null;
+  }
+
+  @Override
+  public void addHeaders(HttpRequestBase request, DefaultHttpClient client) {
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BasicAuthHeaderProvider.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BasicAuthHeaderProvider.java
new file mode 100644
index 000000000..d8a371ddc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BasicAuthHeaderProvider.java
@@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.auth.Credentials;
+import ch.boye.httpclientandroidlib.auth.UsernamePasswordCredentials;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.auth.BasicScheme;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+import ch.boye.httpclientandroidlib.protocol.BasicHttpContext;
+
+/**
+ * An <code>AuthHeaderProvider</code> that returns an HTTP Basic auth header.
+ */
+public class BasicAuthHeaderProvider implements AuthHeaderProvider {
+  protected final String credentials;
+
+  /**
+   * Constructor.
+   *
+   * @param credentials string in form "user:pass".
+   */
+  public BasicAuthHeaderProvider(String credentials) {
+    this.credentials = credentials;
+  }
+
+  /**
+   * Constructor.
+   *
+   * @param user username.
+   * @param pass password.
+   */
+  public BasicAuthHeaderProvider(String user, String pass) {
+    this(user + ":" + pass);
+  }
+
+  /**
+   * Return a Header object representing an Authentication header for HTTP
+   * Basic.
+   */
+  @Override
+  public Header getAuthHeader(HttpRequestBase request, BasicHttpContext context, DefaultHttpClient client) {
+    Credentials creds = new UsernamePasswordCredentials(credentials);
+
+    // This must be UTF-8 to generate the same Basic Auth headers as desktop for non-ASCII passwords.
+    return BasicScheme.authenticate(creds, "UTF-8", false);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BearerAuthHeaderProvider.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BearerAuthHeaderProvider.java
new file mode 100644
index 000000000..d142d50d9
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BearerAuthHeaderProvider.java
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+/**
+ * An <code>AuthHeaderProvider</code> that returns an Authorization header for
+ * Bearer tokens in the format expected by a Mozilla Firefox Accounts Profile Server.
+ * <p>
+ * See <a href="https://github.com/mozilla/fxa-profile-server/blob/master/docs/API.md">https://github.com/mozilla/fxa-profile-server/blob/master/docs/API.md</a>.
+ */
+public class BearerAuthHeaderProvider extends AbstractBearerTokenAuthHeaderProvider {
+  public BearerAuthHeaderProvider(String token) {
+    super(token);
+  }
+
+  @Override
+  protected String getPrefix() {
+    return "Bearer";
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BrowserIDAuthHeaderProvider.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BrowserIDAuthHeaderProvider.java
new file mode 100644
index 000000000..5004673b3
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/BrowserIDAuthHeaderProvider.java
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+/**
+ * An <code>AuthHeaderProvider</code> that returns an Authorization header for
+ * BrowserID assertions in the format expected by a Mozilla Services Token
+ * Server.
+ * <p>
+ * See <a href="http://docs.services.mozilla.com/token/apis.html">http://docs.services.mozilla.com/token/apis.html</a>.
+ */
+public class BrowserIDAuthHeaderProvider extends AbstractBearerTokenAuthHeaderProvider {
+  public BrowserIDAuthHeaderProvider(String assertion) {
+    super(assertion);
+  }
+
+  @Override
+  protected String getPrefix() {
+    return "BrowserID";
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/ConnectionMonitorThread.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/ConnectionMonitorThread.java
new file mode 100644
index 000000000..1a2011771
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/ConnectionMonitorThread.java
@@ -0,0 +1,44 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+/**
+ * Every <code>REAP_INTERVAL</code> milliseconds, wake up
+ * and expire any connections that need cleaning up.
+ *
+ * When we're told to shut down, take the connection manager
+ * with us.
+ */
+public class ConnectionMonitorThread extends Thread {
+  private static final long REAP_INTERVAL = 5000;     // 5 seconds.
+  private static final String LOG_TAG = "ConnectionMonitorThread";
+
+  private volatile boolean stopping;
+
+  @Override
+  public void run() {
+    try {
+      while (!stopping) {
+        synchronized (this) {
+          wait(REAP_INTERVAL);
+          BaseResource.closeExpiredConnections();
+        }
+      }
+    } catch (InterruptedException e) {
+      Logger.trace(LOG_TAG, "Interrupted.");
+    }
+    BaseResource.shutdownConnectionManager();
+  }
+
+  public void shutdown() {
+    Logger.debug(LOG_TAG, "ConnectionMonitorThread told to shut down.");
+    stopping = true;
+    synchronized (this) {
+      notifyAll();
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/GzipNonChunkedCompressingEntity.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/GzipNonChunkedCompressingEntity.java
new file mode 100644
index 000000000..1e238c022
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/GzipNonChunkedCompressingEntity.java
@@ -0,0 +1,92 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import ch.boye.httpclientandroidlib.HttpEntity;
+import ch.boye.httpclientandroidlib.client.entity.GzipCompressingEntity;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * Wrapping entity that compresses content when {@link #writeTo writing}.
+ *
+ * This differs from {@link GzipCompressingEntity} in that it does not chunk
+ * the sent data, therefore replacing the "Transfer-Encoding" HTTP header with
+ * the "Content-Length" header required by some servers.
+ *
+ * However, to measure the content length, the gzipped content will be temporarily
+ * stored in memory so be careful what content you send!
+ */
+public class GzipNonChunkedCompressingEntity extends GzipCompressingEntity {
+    final int MAX_BUFFER_SIZE_BYTES = 10 * 1000 * 1000; // 10 MB.
+
+    private byte[] gzippedContent;
+
+    public GzipNonChunkedCompressingEntity(final HttpEntity entity) {
+        super(entity);
+    }
+
+    /**
+     * @return content length for gzipped content or -1 if there is an error
+     */
+    @Override
+    public long getContentLength() {
+        try {
+            initBuffer();
+        } catch (final IOException e) {
+            // GzipCompressingEntity always returns -1 in which case a 'Content-Length' header is omitted.
+            // Presumably, without it the request will fail (either client-side or server-side).
+            return -1;
+        }
+        return gzippedContent.length;
+    }
+
+    @Override
+    public boolean isChunked() {
+        // "Content-Length" & chunked encoding are mutually exclusive:
+        //   https://en.wikipedia.org/wiki/Chunked_transfer_encoding
+        return false;
+    }
+
+    @Override
+    public InputStream getContent() throws IOException {
+        initBuffer();
+        return new ByteArrayInputStream(gzippedContent);
+    }
+
+    @Override
+    public void writeTo(final OutputStream outstream) throws IOException {
+        initBuffer();
+        outstream.write(gzippedContent);
+    }
+
+    private void initBuffer() throws IOException {
+        if (gzippedContent != null) {
+            return;
+        }
+
+        final long unzippedContentLength = wrappedEntity.getContentLength();
+        if (unzippedContentLength > MAX_BUFFER_SIZE_BYTES) {
+            throw new IOException(
+                    "Wrapped entity content length, " + unzippedContentLength + " bytes, exceeds max: " + MAX_BUFFER_SIZE_BYTES);
+        }
+
+        // The buffer size needed by the gzipped content should be smaller than this,
+        // but it's more efficient just to allocate one larger buffer than allocate
+        // twice if the gzipped content is too large for the default buffer.
+        final ByteArrayOutputStream s = new ByteArrayOutputStream((int) unzippedContentLength);
+        try {
+            super.writeTo(s);
+        } finally {
+            s.close();
+        }
+
+        gzippedContent = s.toByteArray();
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HMACAuthHeaderProvider.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HMACAuthHeaderProvider.java
new file mode 100644
index 000000000..5314d345b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HMACAuthHeaderProvider.java
@@ -0,0 +1,257 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+
+import org.mozilla.apache.commons.codec.binary.Base64;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.Utils;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.client.methods.HttpUriRequest;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+import ch.boye.httpclientandroidlib.message.BasicHeader;
+import ch.boye.httpclientandroidlib.protocol.BasicHttpContext;
+
+/**
+ * An <code>AuthHeaderProvider</code> that returns an Authorization header for
+ * HMAC-SHA1-signed requests in the format expected by Mozilla Services
+ * identity-attached services and specified by the MAC Authentication spec, available at
+ * <a href="https://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac">https://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac</a>.
+ * <p>
+ * See <a href="https://wiki.mozilla.org/Services/Sagrada/ServiceClientFlow#Access">https://wiki.mozilla.org/Services/Sagrada/ServiceClientFlow#Access</a>.
+ */
+public class HMACAuthHeaderProvider implements AuthHeaderProvider {
+  public static final String LOG_TAG = "HMACAuthHeaderProvider";
+
+  public static final int NONCE_LENGTH_IN_BYTES = 8;
+
+  public static final String HMAC_SHA1_ALGORITHM = "hmacSHA1";
+
+  public final String identifier;
+  public final String key;
+
+  public HMACAuthHeaderProvider(String identifier, String key) {
+    // Validate identifier string.  From the MAC Authentication spec:
+    // id             = "id" "=" string-value
+    // string-value   = ( <"> plain-string <"> ) / plain-string
+    // plain-string   = 1*( %x20-21 / %x23-5B / %x5D-7E )
+    // We add quotes around the id string, so input identifier must be a plain-string.
+    if (identifier == null) {
+      throw new IllegalArgumentException("identifier must not be null.");
+    }
+    if (!isPlainString(identifier)) {
+      throw new IllegalArgumentException("identifier must be a plain-string.");
+    }
+
+    if (key == null) {
+      throw new IllegalArgumentException("key must not be null.");
+    }
+
+    this.identifier = identifier;
+    this.key = key;
+  }
+
+  @Override
+  public Header getAuthHeader(HttpRequestBase request, BasicHttpContext context, DefaultHttpClient client) throws GeneralSecurityException {
+    long timestamp = System.currentTimeMillis() / 1000;
+    String nonce = Base64.encodeBase64String(Utils.generateRandomBytes(NONCE_LENGTH_IN_BYTES));
+    String extra = "";
+
+    try {
+      return getAuthHeader(request, context, client, timestamp, nonce, extra);
+    } catch (InvalidKeyException | NoSuchAlgorithmException | UnsupportedEncodingException e) {
+      // We lie a little and make every exception a GeneralSecurityException.
+      throw new GeneralSecurityException(e);
+    }
+  }
+
+  /**
+   * Test if input is a <code>plain-string</code>.
+   * <p>
+   * A plain-string is defined by the MAC Authentication spec as
+   * <code>plain-string   = 1*( %x20-21 / %x23-5B / %x5D-7E )</code>.
+   *
+   * @param input
+   *          as a String of "US-ASCII" bytes.
+   * @return true if input is a <code>plain-string</code>; false otherwise.
+   * @throws UnsupportedEncodingException
+   */
+  protected static boolean isPlainString(String input) {
+    if (input == null || input.length() == 0) {
+      return false;
+    }
+
+    byte[] bytes;
+    try {
+      bytes = input.getBytes("US-ASCII");
+    } catch (UnsupportedEncodingException e) {
+      // Should never happen.
+      Logger.warn(LOG_TAG, "Got exception in isPlainString; returning false.", e);
+      return false;
+    }
+
+    for (byte b : bytes) {
+      if ((0x20 <= b && b <= 0x21) || (0x23 <= b && b <= 0x5B) || (0x5D <= b && b <= 0x7E)) {
+        continue;
+      }
+      return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Helper function that generates an HTTP Authorization header given
+   * additional MAC Authentication specific data.
+   *
+   * @throws UnsupportedEncodingException
+   * @throws NoSuchAlgorithmException 
+   * @throws InvalidKeyException 
+   */
+  protected Header getAuthHeader(HttpRequestBase request, BasicHttpContext context, DefaultHttpClient client,
+      long timestamp, String nonce, String extra)
+      throws UnsupportedEncodingException, InvalidKeyException, NoSuchAlgorithmException {
+    // Validate timestamp.  From the MAC Authentication spec:
+    // timestamp      = 1*DIGIT
+    // This is equivalent to timestamp >= 0.
+    if (timestamp < 0) {
+      throw new IllegalArgumentException("timestamp must contain only [0-9].");
+    }
+
+    // Validate nonce string.  From the MAC Authentication spec:
+    // nonce          = "nonce" "=" string-value
+    // string-value   = ( <"> plain-string <"> ) / plain-string
+    // plain-string   = 1*( %x20-21 / %x23-5B / %x5D-7E )
+    // We add quotes around the nonce string, so input nonce must be a plain-string.
+    if (nonce == null) {
+      throw new IllegalArgumentException("nonce must not be null.");
+    }
+    if (nonce.length() == 0) {
+      throw new IllegalArgumentException("nonce must not be empty.");
+    }
+    if (!isPlainString(nonce)) {
+      throw new IllegalArgumentException("nonce must be a plain-string.");
+    }
+
+    // Validate extra string.  From the MAC Authentication spec:
+    // ext            = "ext" "=" string-value
+    // string-value   = ( <"> plain-string <"> ) / plain-string
+    // plain-string   = 1*( %x20-21 / %x23-5B / %x5D-7E )
+    // We add quotes around the extra string, so input extra must be a plain-string.
+    // We break the spec by allowing ext to be an empty string, i.e. to match 0*(...).
+    if (extra == null) {
+      throw new IllegalArgumentException("extra must not be null.");
+    }
+    if (extra.length() > 0 && !isPlainString(extra)) {
+      throw new IllegalArgumentException("extra must be a plain-string.");
+    }
+
+    String requestString = getRequestString(request, timestamp, nonce, extra);
+    String macString = getSignature(requestString, this.key);
+
+    String h = "MAC id=\"" + this.identifier + "\", " +
+               "ts=\""     + timestamp       + "\", " +
+               "nonce=\""  + nonce           + "\", " +
+               "mac=\""    + macString       + "\"";
+
+    if (extra != null) {
+      h += ", ext=\"" + extra + "\"";
+    }
+
+    Header header = new BasicHeader("Authorization", h);
+
+    return header;
+  }
+
+  protected static byte[] sha1(byte[] message, byte[] key)
+      throws NoSuchAlgorithmException, InvalidKeyException {
+
+    SecretKeySpec keySpec = new SecretKeySpec(key, HMAC_SHA1_ALGORITHM);
+
+    Mac hasher = Mac.getInstance(HMAC_SHA1_ALGORITHM);
+    hasher.init(keySpec);
+    hasher.update(message);
+
+    byte[] hmac = hasher.doFinal();
+
+    return hmac;
+  }
+
+  /**
+   * Sign an HMAC request string.
+   *
+   * @param requestString to sign.
+   * @param key as <code>String</code>.
+   * @return signature as base-64 encoded string.
+   * @throws InvalidKeyException
+   * @throws NoSuchAlgorithmException
+   * @throws UnsupportedEncodingException
+   */
+  protected static String getSignature(String requestString, String key)
+      throws InvalidKeyException, NoSuchAlgorithmException, UnsupportedEncodingException {
+    String macString = Base64.encodeBase64String(sha1(requestString.getBytes("UTF-8"), key.getBytes("UTF-8")));
+
+    return macString;
+  }
+
+  /**
+   * Generate an HMAC request string.
+   * <p>
+   * This method trusts its inputs to be valid as per the MAC Authentication spec.
+   *
+   * @param request HTTP request.
+   * @param timestamp to use.
+   * @param nonce to use.
+   * @param extra to use.
+   * @return request string.
+   */
+  protected static String getRequestString(HttpUriRequest request, long timestamp, String nonce, String extra) {
+    String method = request.getMethod().toUpperCase();
+
+    URI uri = request.getURI();
+    String host = uri.getHost();
+
+    String path = uri.getRawPath();
+    if (uri.getRawQuery() != null) {
+      path += "?";
+      path += uri.getRawQuery();
+    }
+    if (uri.getRawFragment() != null) {
+      path += "#";
+      path += uri.getRawFragment();
+    }
+
+    int port = uri.getPort();
+    String scheme = uri.getScheme();
+    if (port != -1) {
+    } else if ("http".equalsIgnoreCase(scheme)) {
+      port = 80;
+    } else if ("https".equalsIgnoreCase(scheme)) {
+      port = 443;
+    } else {
+      throw new IllegalArgumentException("Unsupported URI scheme: " + scheme + ".");
+    }
+
+    String requestString = timestamp + "\n" +
+        nonce       + "\n" +
+        method      + "\n" +
+        path        + "\n" +
+        host        + "\n" +
+        port        + "\n" +
+        extra       + "\n";
+
+    return requestString;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HandleProgressException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HandleProgressException.java
new file mode 100644
index 000000000..27ec74b66
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HandleProgressException.java
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class HandleProgressException extends SyncException {
+  private static final long serialVersionUID = -4444933937013161059L;
+
+  public HandleProgressException(Exception ex) {
+    super(ex);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HawkAuthHeaderProvider.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HawkAuthHeaderProvider.java
new file mode 100644
index 000000000..2bdd5604a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HawkAuthHeaderProvider.java
@@ -0,0 +1,403 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Locale;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+
+import org.mozilla.apache.commons.codec.binary.Base64;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.Utils;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.HttpEntity;
+import ch.boye.httpclientandroidlib.HttpEntityEnclosingRequest;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.client.methods.HttpUriRequest;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+import ch.boye.httpclientandroidlib.message.BasicHeader;
+import ch.boye.httpclientandroidlib.protocol.BasicHttpContext;
+
+/**
+ * An <code>AuthHeaderProvider</code> that returns an Authorization header for
+ * Hawk: <a href="https://github.com/hueniverse/hawk">https://github.com/hueniverse/hawk</a>.
+ *
+ * Hawk is an HTTP authentication scheme using a message authentication code
+ * (MAC) algorithm to provide partial HTTP request cryptographic verification.
+ * Hawk is the successor to the HMAC authentication scheme.
+ */
+public class HawkAuthHeaderProvider implements AuthHeaderProvider {
+  public static final String LOG_TAG = HawkAuthHeaderProvider.class.getSimpleName();
+
+  public static final int HAWK_HEADER_VERSION = 1;
+
+  protected static final int NONCE_LENGTH_IN_BYTES = 8;
+  protected static final String HMAC_SHA256_ALGORITHM = "hmacSHA256";
+
+  protected final String id;
+  protected final byte[] key;
+  protected final boolean includePayloadHash;
+  protected final long skewSeconds;
+
+  /**
+   * Create a Hawk Authorization header provider.
+   * <p>
+   * Hawk specifies no mechanism by which a client receives an
+   * identifier-and-key pair from the server.
+   * <p>
+   * Hawk requests can include a payload verification hash with requests that
+   * enclose an entity (PATCH, POST, and PUT requests).  <b>You should default
+   * to including the payload verification hash<b> unless you have a good reason
+   * not to -- the server can always ignore payload verification hashes provided
+   * by the client.
+   *
+   * @param id
+   *          to name requests with.
+   * @param key
+   *          to sign request with.
+   *
+   * @param includePayloadHash
+   *          true if payload verification hash should be included in signed
+   *          request header. See <a href="https://github.com/hueniverse/hawk#payload-validation">https://github.com/hueniverse/hawk#payload-validation</a>.
+   *
+   * @param skewSeconds
+   *          a number of seconds by which to skew the current time when
+   *          computing a header.
+   */
+  public HawkAuthHeaderProvider(String id, byte[] key, boolean includePayloadHash, long skewSeconds) {
+    if (id == null) {
+      throw new IllegalArgumentException("id must not be null");
+    }
+    if (key == null) {
+      throw new IllegalArgumentException("key must not be null");
+    }
+    this.id = id;
+    this.key = key;
+    this.includePayloadHash = includePayloadHash;
+    this.skewSeconds = skewSeconds;
+  }
+
+  /**
+   * @return the current time in milliseconds.
+   */
+  @SuppressWarnings("static-method")
+  protected long now() {
+    return System.currentTimeMillis();
+  }
+
+  /**
+   * @return the current time in seconds, adjusted for skew. This should
+   *         approximate the server's timestamp.
+   */
+  protected long getTimestampSeconds() {
+    return (now() / 1000) + skewSeconds;
+  }
+
+  @Override
+  public Header getAuthHeader(HttpRequestBase request, BasicHttpContext context, DefaultHttpClient client) throws GeneralSecurityException {
+    long timestamp = getTimestampSeconds();
+    String nonce = Base64.encodeBase64String(Utils.generateRandomBytes(NONCE_LENGTH_IN_BYTES));
+    String extra = "";
+
+    try {
+      return getAuthHeader(request, context, client, timestamp, nonce, extra, this.includePayloadHash);
+    } catch (Exception e) {
+      // We lie a little and make every exception a GeneralSecurityException.
+      throw new GeneralSecurityException(e);
+    }
+  }
+
+  /**
+   * Helper function that generates an HTTP Authorization: Hawk header given
+   * additional Hawk specific data.
+   *
+   * @throws NoSuchAlgorithmException
+   * @throws InvalidKeyException
+   * @throws IOException
+   */
+  protected Header getAuthHeader(HttpRequestBase request, BasicHttpContext context, DefaultHttpClient client,
+      long timestamp, String nonce, String extra, boolean includePayloadHash)
+          throws InvalidKeyException, NoSuchAlgorithmException, IOException {
+    if (timestamp < 0) {
+      throw new IllegalArgumentException("timestamp must contain only [0-9].");
+    }
+
+    if (nonce == null) {
+      throw new IllegalArgumentException("nonce must not be null.");
+    }
+    if (nonce.length() == 0) {
+      throw new IllegalArgumentException("nonce must not be empty.");
+    }
+
+    String payloadHash = null;
+    if (includePayloadHash) {
+      payloadHash = getPayloadHashString(request);
+    } else {
+      Logger.debug(LOG_TAG, "Configured to not include payload hash for this request.");
+    }
+
+    String app = null;
+    String dlg = null;
+    String requestString = getRequestString(request, "header", timestamp, nonce, payloadHash, extra, app, dlg);
+    String macString = getSignature(requestString.getBytes("UTF-8"), this.key);
+
+    StringBuilder sb = new StringBuilder();
+    sb.append("Hawk id=\"");
+    sb.append(this.id);
+    sb.append("\", ");
+    sb.append("ts=\"");
+    sb.append(timestamp);
+    sb.append("\", ");
+    sb.append("nonce=\"");
+    sb.append(nonce);
+    sb.append("\", ");
+    if (payloadHash != null) {
+      sb.append("hash=\"");
+      sb.append(payloadHash);
+      sb.append("\", ");
+    }
+    if (extra != null && extra.length() > 0) {
+      sb.append("ext=\"");
+      sb.append(escapeExtraHeaderAttribute(extra));
+      sb.append("\", ");
+    }
+    sb.append("mac=\"");
+    sb.append(macString);
+    sb.append("\"");
+
+    return new BasicHeader("Authorization", sb.toString());
+  }
+
+  /**
+   * Get the payload verification hash for the given request, if possible.
+   * <p>
+   * Returns null if the request does not enclose an entity (is not an HTTP
+   * PATCH, POST, or PUT). Throws if the payload verification hash cannot be
+   * computed.
+   *
+   * @param request
+   *          to compute hash for.
+   * @return verification hash, or null if the request does not enclose an entity.
+   * @throws IllegalArgumentException if the request does not enclose a valid non-null entity.
+   * @throws UnsupportedEncodingException
+   * @throws NoSuchAlgorithmException
+   * @throws IOException
+   */
+  protected static String getPayloadHashString(HttpRequestBase request)
+      throws UnsupportedEncodingException, NoSuchAlgorithmException, IOException, IllegalArgumentException {
+    final boolean shouldComputePayloadHash = request instanceof HttpEntityEnclosingRequest;
+    if (!shouldComputePayloadHash) {
+      Logger.debug(LOG_TAG, "Not computing payload verification hash for non-enclosing request.");
+      return null;
+    }
+    if (!(request instanceof HttpEntityEnclosingRequest)) {
+      throw new IllegalArgumentException("Cannot compute payload verification hash for enclosing request without an entity");
+    }
+    final HttpEntity entity = ((HttpEntityEnclosingRequest) request).getEntity();
+    if (entity == null) {
+      throw new IllegalArgumentException("Cannot compute payload verification hash for enclosing request with a null entity");
+    }
+    return Base64.encodeBase64String(getPayloadHash(entity));
+  }
+
+  /**
+   * Escape the user-provided extra string for the ext="" header attribute.
+   * <p>
+   * Hawk escapes the header ext="" attribute differently than it does the extra
+   * line in the normalized request string.
+   * <p>
+   * See <a href="https://github.com/hueniverse/hawk/blob/871cc597973110900467bd3dfb84a3c892f678fb/lib/browser.js#L385">https://github.com/hueniverse/hawk/blob/871cc597973110900467bd3dfb84a3c892f678fb/lib/browser.js#L385</a>.
+   *
+   * @param extra to escape.
+   * @return extra escaped for the ext="" header attribute.
+   */
+  protected static String escapeExtraHeaderAttribute(String extra) {
+    return extra.replaceAll("\\\\", "\\\\").replaceAll("\"", "\\\"");
+  }
+
+  /**
+   * Escape the user-provided extra string for inserting into the normalized
+   * request string.
+   * <p>
+   * Hawk escapes the header ext="" attribute differently than it does the extra
+   * line in the normalized request string.
+   * <p>
+   * See <a href="https://github.com/hueniverse/hawk/blob/871cc597973110900467bd3dfb84a3c892f678fb/lib/crypto.js#L67">https://github.com/hueniverse/hawk/blob/871cc597973110900467bd3dfb84a3c892f678fb/lib/crypto.js#L67</a>.
+   *
+   * @param extra to escape.
+   * @return extra escaped for the normalized request string.
+   */
+  protected static String escapeExtraString(String extra) {
+    return extra.replaceAll("\\\\", "\\\\").replaceAll("\n", "\\n");
+  }
+
+  /**
+   * Return the content type with no parameters (pieces following ;).
+   *
+   * @param contentTypeHeader to interrogate.
+   * @return base content type.
+   */
+  protected static String getBaseContentType(Header contentTypeHeader) {
+    if (contentTypeHeader == null) {
+      throw new IllegalArgumentException("contentTypeHeader must not be null.");
+    }
+    String contentType = contentTypeHeader.getValue();
+    if (contentType == null) {
+      throw new IllegalArgumentException("contentTypeHeader value must not be null.");
+    }
+    int index = contentType.indexOf(";");
+    if (index < 0) {
+      return contentType.trim();
+    }
+    return contentType.substring(0, index).trim();
+  }
+
+  /**
+   * Generate the SHA-256 hash of a normalized Hawk payload generated from an
+   * HTTP entity.
+   * <p>
+   * <b>Warning:</b> the entity <b>must</b> be repeatable.  If it is not, this
+   * code throws an <code>IllegalArgumentException</code>.
+   * <p>
+   * This is under-specified; the code here was reverse engineered from the code
+   * at
+   * <a href="https://github.com/hueniverse/hawk/blob/871cc597973110900467bd3dfb84a3c892f678fb/lib/crypto.js#L81">https://github.com/hueniverse/hawk/blob/871cc597973110900467bd3dfb84a3c892f678fb/lib/crypto.js#L81</a>.
+   * @param entity to normalize and hash.
+   * @return hash.
+   * @throws IllegalArgumentException if entity is not repeatable.
+   */
+  protected static byte[] getPayloadHash(HttpEntity entity) throws UnsupportedEncodingException, IOException, NoSuchAlgorithmException {
+    if (!entity.isRepeatable()) {
+      throw new IllegalArgumentException("entity must be repeatable");
+    }
+    final MessageDigest digest = MessageDigest.getInstance("SHA-256");
+    digest.update(("hawk." + HAWK_HEADER_VERSION + ".payload\n").getBytes("UTF-8"));
+    digest.update(getBaseContentType(entity.getContentType()).getBytes("UTF-8"));
+    digest.update("\n".getBytes("UTF-8"));
+    InputStream stream = entity.getContent();
+    try {
+      int numRead;
+      byte[] buffer = new byte[4096];
+      while (-1 != (numRead = stream.read(buffer))) {
+        if (numRead > 0) {
+          digest.update(buffer, 0, numRead);
+        }
+      }
+      digest.update("\n".getBytes("UTF-8")); // Trailing newline is specified by Hawk.
+      return digest.digest();
+    } finally {
+      stream.close();
+    }
+  }
+
+  /**
+   * Generate a normalized Hawk request string. This is under-specified; the
+   * code here was reverse engineered from the code at
+   * <a href="https://github.com/hueniverse/hawk/blob/871cc597973110900467bd3dfb84a3c892f678fb/lib/crypto.js#L55">https://github.com/hueniverse/hawk/blob/871cc597973110900467bd3dfb84a3c892f678fb/lib/crypto.js#L55</a>.
+   * <p>
+   * This method trusts its inputs to be valid.
+   */
+  protected static String getRequestString(HttpUriRequest request, String type, long timestamp, String nonce, String hash, String extra, String app, String dlg) {
+    String method = request.getMethod().toUpperCase(Locale.US);
+
+    URI uri = request.getURI();
+    String host = uri.getHost();
+
+    String path = uri.getRawPath();
+    if (uri.getRawQuery() != null) {
+      path += "?";
+      path += uri.getRawQuery();
+    }
+    if (uri.getRawFragment() != null) {
+      path += "#";
+      path += uri.getRawFragment();
+    }
+
+    int port = uri.getPort();
+    String scheme = uri.getScheme();
+    if (port != -1) {
+    } else if ("http".equalsIgnoreCase(scheme)) {
+      port = 80;
+    } else if ("https".equalsIgnoreCase(scheme)) {
+      port = 443;
+    } else {
+      throw new IllegalArgumentException("Unsupported URI scheme: " + scheme + ".");
+    }
+
+    StringBuilder sb = new StringBuilder();
+    sb.append("hawk.");
+    sb.append(HAWK_HEADER_VERSION);
+    sb.append('.');
+    sb.append(type);
+    sb.append('\n');
+    sb.append(timestamp);
+    sb.append('\n');
+    sb.append(nonce);
+    sb.append('\n');
+    sb.append(method);
+    sb.append('\n');
+    sb.append(path);
+    sb.append('\n');
+    sb.append(host);
+    sb.append('\n');
+    sb.append(port);
+    sb.append('\n');
+    if (hash != null) {
+      sb.append(hash);
+    }
+    sb.append("\n");
+    if (extra != null && extra.length() > 0) {
+      sb.append(escapeExtraString(extra));
+    }
+    sb.append("\n");
+    if (app != null) {
+      sb.append(app);
+      sb.append("\n");
+      if (dlg != null) {
+        sb.append(dlg);
+      }
+      sb.append("\n");
+    }
+
+    return sb.toString();
+  }
+
+  protected static byte[] hmacSha256(byte[] message, byte[] key)
+      throws NoSuchAlgorithmException, InvalidKeyException {
+
+    SecretKeySpec keySpec = new SecretKeySpec(key, HMAC_SHA256_ALGORITHM);
+
+    Mac hasher = Mac.getInstance(HMAC_SHA256_ALGORITHM);
+    hasher.init(keySpec);
+    hasher.update(message);
+
+    return hasher.doFinal();
+  }
+
+  /**
+   * Sign a Hawk request string.
+   *
+   * @param requestString to sign.
+   * @param key as <code>String</code>.
+   * @return signature as base-64 encoded string.
+   * @throws InvalidKeyException
+   * @throws NoSuchAlgorithmException
+   * @throws UnsupportedEncodingException
+   */
+  protected static String getSignature(byte[] requestString, byte[] key)
+      throws InvalidKeyException, NoSuchAlgorithmException, UnsupportedEncodingException {
+    return Base64.encodeBase64String(hmacSha256(requestString, key));
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HttpResponseObserver.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HttpResponseObserver.java
new file mode 100644
index 000000000..24b37a0e6
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/HttpResponseObserver.java
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.methods.HttpUriRequest;
+
+public interface HttpResponseObserver {
+  /**
+   * Observe an HTTP response.
+   * @param request
+   *          The <code>HttpUriRequest<code> that elicited the response.
+   *
+   * @param response
+   *          The <code>HttpResponse</code> to observe.
+   */
+  public void observeHttpResponse(HttpUriRequest request, HttpResponse response);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/MozResponse.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/MozResponse.java
new file mode 100644
index 000000000..3f76f929f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/MozResponse.java
@@ -0,0 +1,225 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.util.Scanner;
+
+import org.json.simple.JSONArray;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonArrayJSONException;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.HttpEntity;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.HttpStatus;
+import ch.boye.httpclientandroidlib.impl.cookie.DateParseException;
+import ch.boye.httpclientandroidlib.impl.cookie.DateUtils;
+
+public class MozResponse {
+  private static final String LOG_TAG = "MozResponse";
+
+  private static final String HEADER_RETRY_AFTER = "retry-after";
+
+  protected HttpResponse response;
+  private String body = null;
+
+  public HttpResponse httpResponse() {
+    return this.response;
+  }
+
+  public int getStatusCode() {
+    return this.response.getStatusLine().getStatusCode();
+  }
+
+  public boolean wasSuccessful() {
+    return this.getStatusCode() == 200;
+  }
+
+  public boolean isInvalidAuthentication() {
+    return this.getStatusCode() == HttpStatus.SC_UNAUTHORIZED;
+  }
+
+  /**
+   * Fetch the content type of the HTTP response body.
+   *
+   * @return a <code>Header</code> instance, or <code>null</code> if there was
+   *         no body or no valid Content-Type.
+   */
+  public Header getContentType() {
+    HttpEntity entity = this.response.getEntity();
+    if (entity == null) {
+      return null;
+    }
+    return entity.getContentType();
+  }
+
+  private static boolean missingHeader(String value) {
+    return value == null ||
+           value.trim().length() == 0;
+  }
+
+  public String body() throws IllegalStateException, IOException {
+    if (body != null) {
+      return body;
+    }
+    final HttpEntity entity = this.response.getEntity();
+    if (entity == null) {
+      body = null;
+      return null;
+    }
+
+    InputStreamReader is = new InputStreamReader(entity.getContent());
+    // Oh, Java, you are so evil.
+    body = new Scanner(is).useDelimiter("\\A").next();
+    return body;
+  }
+
+  /**
+   * Return the body as a <b>non-null</b> <code>ExtendedJSONObject</code>.
+   *
+   * @return A non-null <code>ExtendedJSONObject</code>.
+   *
+   * @throws IllegalStateException
+   * @throws IOException
+   * @throws NonObjectJSONException
+   */
+  public ExtendedJSONObject jsonObjectBody() throws IllegalStateException, IOException, NonObjectJSONException {
+    if (body != null) {
+      // Do it from the cached String.
+      return new ExtendedJSONObject(body);
+    }
+
+    HttpEntity entity = this.response.getEntity();
+    if (entity == null) {
+      throw new IOException("no entity");
+    }
+
+    InputStream content = entity.getContent();
+    try {
+      Reader in = new BufferedReader(new InputStreamReader(content, "UTF-8"));
+      return new ExtendedJSONObject(in);
+    } finally {
+      content.close();
+    }
+  }
+
+  public JSONArray jsonArrayBody() throws NonArrayJSONException, IOException {
+    final JSONParser parser = new JSONParser();
+    try {
+      if (body != null) {
+        // Do it from the cached String.
+        return (JSONArray) parser.parse(body);
+      }
+
+      final HttpEntity entity = this.response.getEntity();
+      if (entity == null) {
+        throw new IOException("no entity");
+      }
+
+      final InputStream content = entity.getContent();
+      final Reader in = new BufferedReader(new InputStreamReader(content, "UTF-8"));
+      try {
+        return (JSONArray) parser.parse(in);
+      } finally {
+        in.close();
+      }
+    } catch (ClassCastException | ParseException e) {
+      NonArrayJSONException exception = new NonArrayJSONException("value must be a json array");
+      exception.initCause(e);
+      throw exception;
+    }
+  }
+
+  protected boolean hasHeader(String h) {
+    return this.response.containsHeader(h);
+  }
+
+  public MozResponse(HttpResponse res) {
+    response = res;
+  }
+
+  protected String getNonMissingHeader(String h) {
+    if (!this.hasHeader(h)) {
+      return null;
+    }
+
+    final Header header = this.response.getFirstHeader(h);
+    final String value = header.getValue();
+    if (missingHeader(value)) {
+      Logger.warn(LOG_TAG, h + " header present but empty.");
+      return null;
+    }
+    return value;
+  }
+
+  protected long getLongHeader(String h) throws NumberFormatException {
+    final String value = getNonMissingHeader(h);
+    if (value == null) {
+      return -1L;
+    }
+    return Long.parseLong(value, 10);
+  }
+
+  protected int getIntegerHeader(String h) throws NumberFormatException {
+    final String value = getNonMissingHeader(h);
+    if (value == null) {
+      return -1;
+    }
+    return Integer.parseInt(value, 10);
+  }
+
+  /**
+   * @return A number of seconds, or -1 if the 'Retry-After' header was not present.
+   */
+  public int retryAfterInSeconds() throws NumberFormatException {
+    final String retryAfter = getNonMissingHeader(HEADER_RETRY_AFTER);
+    if (retryAfter == null) {
+      return -1;
+    }
+
+    try {
+      return Integer.parseInt(retryAfter, 10);
+    } catch (NumberFormatException e) {
+      // Fall through to try date format.
+    }
+
+    try {
+      final long then = DateUtils.parseDate(retryAfter).getTime();
+      final long now  = System.currentTimeMillis();
+      return (int)((then - now) / 1000);     // Convert milliseconds to seconds.
+    } catch (DateParseException e) {
+      Logger.warn(LOG_TAG, "Retry-After header neither integer nor date: " + retryAfter);
+      return -1;
+    }
+  }
+
+  /**
+   * @return A number of seconds, or -1 if the 'Backoff' header was not
+   *         present.
+   */
+  public int backoffInSeconds() throws NumberFormatException {
+    return this.getIntegerHeader("backoff");
+  }
+
+  public void logResponseBody(final String logTag) {
+    if (!Logger.LOG_PERSONAL_INFORMATION) {
+      return;
+    }
+    try {
+      Logger.pii(logTag, "Response body: " + body());
+    } catch (Throwable e) {
+      Logger.debug(logTag, "No response body.");
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/Resource.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/Resource.java
new file mode 100644
index 000000000..ab7b98aff
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/Resource.java
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.net.URI;
+
+import ch.boye.httpclientandroidlib.HttpEntity;
+
+public interface Resource {
+  public abstract URI getURI();
+  public abstract String getURIString();
+  public abstract String getHostname();
+  public abstract void get();
+  public abstract void delete();
+  public abstract void post(HttpEntity body);
+  public abstract void patch(HttpEntity body);
+  public abstract void put(HttpEntity body);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/ResourceDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/ResourceDelegate.java
new file mode 100644
index 000000000..0dea9432b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/ResourceDelegate.java
@@ -0,0 +1,55 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.io.IOException;
+import java.security.GeneralSecurityException;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.ClientProtocolException;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+
+/**
+ * ResourceDelegate implementers must ensure that HTTP responses
+ * are fully consumed to ensure that connections are returned to
+ * the pool:
+ *
+ *          EntityUtils.consume(entity);
+ * @author rnewman
+ *
+ */
+public interface ResourceDelegate {
+  // Request augmentation.
+  AuthHeaderProvider getAuthHeaderProvider();
+  void addHeaders(HttpRequestBase request, DefaultHttpClient client);
+
+  /**
+   * The value of the User-Agent header to include with the request.
+   *
+   * @return User-Agent header value; null means do not set User-Agent header.
+   */
+  public String getUserAgent();
+
+  // Response handling.
+
+  /**
+   * Override this to handle an HttpResponse.
+   *
+   * ResourceDelegate implementers <b>must</b> ensure that HTTP responses are
+   * fully consumed to ensure that connections are returned to the pool, for
+   * example by calling <code>EntityUtils.consume(response.getEntity())</code>.
+   */
+  void handleHttpResponse(HttpResponse response);
+  void handleHttpProtocolException(ClientProtocolException e);
+  void handleHttpIOException(IOException e);
+
+  // During preparation.
+  void handleTransportException(GeneralSecurityException e);
+
+  // Connection parameters.
+  int connectionTimeout();
+  int socketTimeout();
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SRPConstants.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SRPConstants.java
new file mode 100644
index 000000000..5dfe660ef
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SRPConstants.java
@@ -0,0 +1,174 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.math.BigInteger;
+
+/**
+ * SRP Group Parameters from
+ * <a href="http://tools.ietf.org/html/rfc5054#appendix-A">Appendix A of RFC 5054</a>.
+ *
+ * The 1024-, 1536-, and 2048-bit groups are taken from software
+ * developed by Tom Wu and Eugene Jhong for the Stanford SRP
+ * distribution, and subsequently proven to be prime.  The larger primes
+ * are taken from [MODP], but generators have been calculated that are
+ * primitive roots of N, unlike the generators in [MODP].
+ *
+ * The 1024-bit and 1536-bit groups <b>MUST</b> be supported.
+ */
+public class SRPConstants {
+  public static class Parameters {
+    public final BigInteger N;
+    public final BigInteger g;
+    public final int bitLength;
+    public final int byteLength;
+    public final int hexLength;
+
+    protected Parameters(String N, long g) {
+      if (N == null) {
+        throw new IllegalArgumentException("N must not be null");
+      }
+      this.N = new BigInteger(N.replaceAll(" ", ""), 16); // Hex.
+      this.g = BigInteger.valueOf(g);
+      this.hexLength = this.N.toString(16).length();
+      this.byteLength = hexLength / 2;
+      this.bitLength = this.byteLength * 8;
+    }
+  }
+
+  public static final Parameters _1024 = new Parameters("" +
+      "EEAF0AB9 ADB38DD6 9C33F80A FA8FC5E8 60726187 75FF3C0B 9EA2314C" +
+      "9C256576 D674DF74 96EA81D3 383B4813 D692C6E0 E0D5D8E2 50B98BE4" +
+      "8E495C1D 6089DAD1 5DC7D7B4 6154D6B6 CE8EF4AD 69B15D49 82559B29" +
+      "7BCF1885 C529F566 660E57EC 68EDBC3C 05726CC0 2FD4CBF4 976EAA9A" +
+      "FD5138FE 8376435B 9FC61D2F C0EB06E3", 2L);
+
+  public static final Parameters _1536 = new Parameters("" +
+      "9DEF3CAF B939277A B1F12A86 17A47BBB DBA51DF4 99AC4C80 BEEEA961" +
+      "4B19CC4D 5F4F5F55 6E27CBDE 51C6A94B E4607A29 1558903B A0D0F843" +
+      "80B655BB 9A22E8DC DF028A7C EC67F0D0 8134B1C8 B9798914 9B609E0B" +
+      "E3BAB63D 47548381 DBC5B1FC 764E3F4B 53DD9DA1 158BFD3E 2B9C8CF5" +
+      "6EDF0195 39349627 DB2FD53D 24B7C486 65772E43 7D6C7F8C E442734A" +
+      "F7CCB7AE 837C264A E3A9BEB8 7F8A2FE9 B8B5292E 5A021FFF 5E91479E" +
+      "8CE7A28C 2442C6F3 15180F93 499A234D CF76E3FE D135F9BB", 2L);
+
+  public static final Parameters _2048 = new Parameters("" +
+      "AC6BDB41 324A9A9B F166DE5E 1389582F AF72B665 1987EE07 FC319294" +
+      "3DB56050 A37329CB B4A099ED 8193E075 7767A13D D52312AB 4B03310D" +
+      "CD7F48A9 DA04FD50 E8083969 EDB767B0 CF609517 9A163AB3 661A05FB" +
+      "D5FAAAE8 2918A996 2F0B93B8 55F97993 EC975EEA A80D740A DBF4FF74" +
+      "7359D041 D5C33EA7 1D281E44 6B14773B CA97B43A 23FB8016 76BD207A" +
+      "436C6481 F1D2B907 8717461A 5B9D32E6 88F87748 544523B5 24B0D57D" +
+      "5EA77A27 75D2ECFA 032CFBDB F52FB378 61602790 04E57AE6 AF874E73" +
+      "03CE5329 9CCC041C 7BC308D8 2A5698F3 A8D0C382 71AE35F8 E9DBFBB6" +
+      "94B5C803 D89F7AE4 35DE236D 525F5475 9B65E372 FCD68EF2 0FA7111F" +
+      "9E4AFF73", 2L);
+
+  public static final Parameters _3072 = new Parameters("" +
+      "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08" +
+      "8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B" +
+      "302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9" +
+      "A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6" +
+      "49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8" +
+      "FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+      "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C" +
+      "180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718" +
+      "3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D" +
+      "04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D" +
+      "B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226" +
+      "1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
+      "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC" +
+      "E0FD108E 4B82D120 A93AD2CA FFFFFFFF FFFFFFFF", 5L);
+
+  public static final Parameters _4096 = new Parameters("" +
+      "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08" +
+      "8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B" +
+      "302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9" +
+      "A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6" +
+      "49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8" +
+      "FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+      "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C" +
+      "180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718" +
+      "3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D" +
+      "04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D" +
+      "B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226" +
+      "1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
+      "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC" +
+      "E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7 88719A10 BDBA5B26" +
+      "99C32718 6AF4E23C 1A946834 B6150BDA 2583E9CA 2AD44CE8 DBBBC2DB" +
+      "04DE8EF9 2E8EFC14 1FBECAA6 287C5947 4E6BC05D 99B2964F A090C3A2" +
+      "233BA186 515BE7ED 1F612970 CEE2D7AF B81BDD76 2170481C D0069127" +
+      "D5B05AA9 93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34063199" +
+      "FFFFFFFF FFFFFFFF", 5L);
+
+  public static final Parameters _6144 = new Parameters("" +
+      "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08" +
+      "8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B" +
+      "302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9" +
+      "A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6" +
+      "49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8" +
+      "FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+      "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C" +
+      "180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718" +
+      "3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D" +
+      "04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D" +
+      "B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226" +
+      "1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
+      "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC" +
+      "E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7 88719A10 BDBA5B26" +
+      "99C32718 6AF4E23C 1A946834 B6150BDA 2583E9CA 2AD44CE8 DBBBC2DB" +
+      "04DE8EF9 2E8EFC14 1FBECAA6 287C5947 4E6BC05D 99B2964F A090C3A2" +
+      "233BA186 515BE7ED 1F612970 CEE2D7AF B81BDD76 2170481C D0069127" +
+      "D5B05AA9 93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34028492" +
+      "36C3FAB4 D27C7026 C1D4DCB2 602646DE C9751E76 3DBA37BD F8FF9406" +
+      "AD9E530E E5DB382F 413001AE B06A53ED 9027D831 179727B0 865A8918" +
+      "DA3EDBEB CF9B14ED 44CE6CBA CED4BB1B DB7F1447 E6CC254B 33205151" +
+      "2BD7AF42 6FB8F401 378CD2BF 5983CA01 C64B92EC F032EA15 D1721D03" +
+      "F482D7CE 6E74FEF6 D55E702F 46980C82 B5A84031 900B1C9E 59E7C97F" +
+      "BEC7E8F3 23A97A7E 36CC88BE 0F1D45B7 FF585AC5 4BD407B2 2B4154AA" +
+      "CC8F6D7E BF48E1D8 14CC5ED2 0F8037E0 A79715EE F29BE328 06A1D58B" +
+      "B7C5DA76 F550AA3D 8A1FBFF0 EB19CCB1 A313D55C DA56C9EC 2EF29632" +
+      "387FE8D7 6E3C0468 043E8F66 3F4860EE 12BF2D5B 0B7474D6 E694F91E" +
+      "6DCC4024 FFFFFFFF FFFFFFFF", 5L);
+
+  public static final Parameters _8192 = new Parameters("" +
+      "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08" +
+      "8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B" +
+      "302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9" +
+      "A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6" +
+      "49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8" +
+      "FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+      "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C" +
+      "180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718" +
+      "3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D" +
+      "04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D" +
+      "B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226" +
+      "1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
+      "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC" +
+      "E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7 88719A10 BDBA5B26" +
+      "99C32718 6AF4E23C 1A946834 B6150BDA 2583E9CA 2AD44CE8 DBBBC2DB" +
+      "04DE8EF9 2E8EFC14 1FBECAA6 287C5947 4E6BC05D 99B2964F A090C3A2" +
+      "233BA186 515BE7ED 1F612970 CEE2D7AF B81BDD76 2170481C D0069127" +
+      "D5B05AA9 93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34028492" +
+      "36C3FAB4 D27C7026 C1D4DCB2 602646DE C9751E76 3DBA37BD F8FF9406" +
+      "AD9E530E E5DB382F 413001AE B06A53ED 9027D831 179727B0 865A8918" +
+      "DA3EDBEB CF9B14ED 44CE6CBA CED4BB1B DB7F1447 E6CC254B 33205151" +
+      "2BD7AF42 6FB8F401 378CD2BF 5983CA01 C64B92EC F032EA15 D1721D03" +
+      "F482D7CE 6E74FEF6 D55E702F 46980C82 B5A84031 900B1C9E 59E7C97F" +
+      "BEC7E8F3 23A97A7E 36CC88BE 0F1D45B7 FF585AC5 4BD407B2 2B4154AA" +
+      "CC8F6D7E BF48E1D8 14CC5ED2 0F8037E0 A79715EE F29BE328 06A1D58B" +
+      "B7C5DA76 F550AA3D 8A1FBFF0 EB19CCB1 A313D55C DA56C9EC 2EF29632" +
+      "387FE8D7 6E3C0468 043E8F66 3F4860EE 12BF2D5B 0B7474D6 E694F91E" +
+      "6DBE1159 74A3926F 12FEE5E4 38777CB6 A932DF8C D8BEC4D0 73B931BA" +
+      "3BC832B6 8D9DD300 741FA7BF 8AFC47ED 2576F693 6BA42466 3AAB639C" +
+      "5AE4F568 3423B474 2BF1C978 238F16CB E39D652D E3FDB8BE FC848AD9" +
+      "22222E04 A4037C07 13EB57A8 1A23F0C7 3473FC64 6CEA306B 4BCBC886" +
+      "2F8385DD FA9D4B7F A2C087E8 79683303 ED5BDD3A 062B3CF5 B3A278A6" +
+      "6D2A13F8 3F44F82D DF310EE0 74AB6A36 4597E899 A0255DC1 64F31CC5" +
+      "0846851D F9AB4819 5DED7EA1 B1D510BD 7EE74D73 FAF36BC3 1ECFA268" +
+      "359046F4 EB879F92 4009438B 481C6CD7 889A002E D5EE382B C9190DA6" +
+      "FC026E47 9558E447 5677E9AA 9E3050E2 765694DF C81F56E8 80B96E71" +
+      "60C980DD 98EDD3DF FFFFFFFF FFFFFFFF", 19L);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncResponse.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncResponse.java
new file mode 100644
index 000000000..177d7aaba
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncResponse.java
@@ -0,0 +1,157 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import android.support.annotation.Nullable;
+
+import org.mozilla.gecko.sync.Utils;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+
+public class SyncResponse extends MozResponse {
+  public static final String X_WEAVE_BACKOFF = "x-weave-backoff";
+  public static final String X_BACKOFF = "x-backoff";
+  public static final String X_LAST_MODIFIED = "x-last-modified";
+  public static final String X_WEAVE_TIMESTAMP = "x-weave-timestamp";
+  public static final String X_WEAVE_RECORDS = "x-weave-records";
+  public static final String X_WEAVE_QUOTA_REMAINING = "x-weave-quota-remaining";
+  public static final String X_WEAVE_ALERT = "x-weave-alert";
+  public static final String X_WEAVE_NEXT_OFFSET = "x-weave-next-offset";
+
+  public SyncResponse(HttpResponse res) {
+    super(res);
+  }
+
+  /**
+   * @return A number of seconds, or -1 if the 'X-Weave-Backoff' header was not
+   *         present.
+   */
+  public int weaveBackoffInSeconds() throws NumberFormatException {
+    return this.getIntegerHeader(X_WEAVE_BACKOFF);
+  }
+
+  /**
+   * @return A number of seconds, or -1 if the 'X-Backoff' header was not
+   *         present.
+   */
+  public int xBackoffInSeconds() throws NumberFormatException {
+    return this.getIntegerHeader(X_BACKOFF);
+  }
+
+  /**
+   * Extract a number of seconds, or -1 if none of the specified headers were present.
+   *
+   * @param includeRetryAfter
+   *          if <code>true</code>, the Retry-After header is excluded. This is
+   *          useful for processing non-error responses where a Retry-After
+   *          header would be unexpected.
+   * @return the maximum of the three possible backoff headers, in seconds.
+   */
+  public int totalBackoffInSeconds(boolean includeRetryAfter) {
+    int retryAfterInSeconds = -1;
+    if (includeRetryAfter) {
+      try {
+        retryAfterInSeconds = retryAfterInSeconds();
+      } catch (NumberFormatException e) {
+      }
+    }
+
+    int weaveBackoffInSeconds = -1;
+    try {
+      weaveBackoffInSeconds = weaveBackoffInSeconds();
+    } catch (NumberFormatException e) {
+    }
+
+    int backoffInSeconds = -1;
+    try {
+      backoffInSeconds = xBackoffInSeconds();
+    } catch (NumberFormatException e) {
+    }
+
+    int totalBackoff = Math.max(retryAfterInSeconds, Math.max(backoffInSeconds, weaveBackoffInSeconds));
+    if (totalBackoff < 0) {
+      return -1;
+    } else {
+      return totalBackoff;
+    }
+  }
+
+  /**
+   * @return A number of milliseconds, or -1 if neither the 'Retry-After',
+   *         'X-Backoff', or 'X-Weave-Backoff' header were present.
+   */
+  public long totalBackoffInMilliseconds() {
+    long totalBackoff = totalBackoffInSeconds(true);
+    if (totalBackoff < 0) {
+      return -1;
+    } else {
+      return 1000 * totalBackoff;
+    }
+  }
+
+  public long normalizedWeaveTimestamp() {
+    return normalizedTimestampForHeader(X_WEAVE_TIMESTAMP);
+  }
+
+  /**
+   * Timestamps returned from a Sync server are decimal numbers of seconds,
+   * e.g., 1323393518.04.
+   *
+   * We want milliseconds since epoch.
+   *
+   * @return milliseconds since the epoch, as a long, or -1 if the header
+   *         was missing or invalid.
+   */
+  public long normalizedTimestampForHeader(String header) {
+    if (!this.hasHeader(header)) {
+      return -1;
+    }
+
+    return Utils.decimalSecondsToMilliseconds(
+            this.response.getFirstHeader(header).getValue()
+    );
+  }
+
+  public int weaveRecords() throws NumberFormatException {
+    return this.getIntegerHeader(X_WEAVE_RECORDS);
+  }
+
+  public int weaveQuotaRemaining() throws NumberFormatException {
+    return this.getIntegerHeader(X_WEAVE_QUOTA_REMAINING);
+  }
+
+  public String weaveAlert() {
+    return this.getNonMissingHeader(X_WEAVE_ALERT);
+  }
+
+  /**
+   * This header may be sent back with multi-record responses where the request included a limit parameter.
+   * Its presence indicates that the number of available records exceeded the given limit.
+   * The value from this header can be passed back in the offset parameter to retrieve additional records.
+   * The value of this header will always be a string of characters from the urlsafe-base64 alphabet.
+   * The specific contents of the string are an implementation detail of the server,
+   * so clients should treat it as an opaque token.
+   *
+   * @return the offset header
+   */
+  public String weaveOffset() {
+    return this.getNonMissingHeader(X_WEAVE_NEXT_OFFSET);
+  }
+
+  /**
+   * This header gives the last-modified time of the target resource as seen during processing of the request,
+   * and will be included in all success responses (200, 201, 204).
+   * When given in response to a write request, this will be equal to the server’s current time and
+   * to the new last-modified time of any BSOs created or changed by the request.
+   * It is similar to the standard HTTP Last-Modified header,
+   * but the value is a decimal timestamp rather than a HTTP-format date.
+   *
+   * @return the last modified header
+   */
+  @Nullable
+  public String lastModified() {
+    return this.getNonMissingHeader(X_LAST_MODIFIED);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageCollectionRequest.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageCollectionRequest.java
new file mode 100644
index 000000000..3ae672f21
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageCollectionRequest.java
@@ -0,0 +1,145 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.URI;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.HttpEntity;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+
+/**
+ * A request class that handles line-by-line responses. Eventually this will
+ * handle real stream processing; for now, just parse the returned body
+ * line-by-line.
+ *
+ * @author rnewman
+ *
+ */
+public class SyncStorageCollectionRequest extends SyncStorageRequest {
+  private static final String LOG_TAG = "CollectionRequest";
+
+  public SyncStorageCollectionRequest(URI uri) {
+    super(uri);
+  }
+
+  protected volatile boolean aborting = false;
+
+  /**
+   * Instruct the request that it should process no more records,
+   * and decline to notify any more delegate callbacks.
+   */
+  public void abort() {
+    aborting = true;
+    try {
+      this.resource.request.abort();
+    } catch (Exception e) {
+      // Just in case.
+      Logger.warn(LOG_TAG, "Got exception in abort: " + e);
+    }
+  }
+
+  @Override
+  protected BaseResourceDelegate makeResourceDelegate(SyncStorageRequest request) {
+    return new SyncCollectionResourceDelegate((SyncStorageCollectionRequest) request);
+  }
+
+  // TODO: this is awful.
+  public class SyncCollectionResourceDelegate extends
+      SyncStorageResourceDelegate {
+
+    private static final String CONTENT_TYPE_INCREMENTAL = "application/newlines";
+    private static final int FETCH_BUFFER_SIZE = 16 * 1024;   // 16K chars.
+
+    SyncCollectionResourceDelegate(SyncStorageCollectionRequest request) {
+      super(request);
+    }
+
+    @Override
+    public void addHeaders(HttpRequestBase request, DefaultHttpClient client) {
+      super.addHeaders(request, client);
+      request.setHeader("Accept", CONTENT_TYPE_INCREMENTAL);
+      // Caller is responsible for setting full=1.
+    }
+
+    @Override
+    public void handleHttpResponse(HttpResponse response) {
+      if (aborting) {
+        return;
+      }
+
+      if (response.getStatusLine().getStatusCode() != 200) {
+        super.handleHttpResponse(response);
+        return;
+      }
+
+      HttpEntity entity = response.getEntity();
+      Header contentType = entity.getContentType();
+      if (!contentType.getValue().startsWith(CONTENT_TYPE_INCREMENTAL)) {
+        // Not incremental!
+        super.handleHttpResponse(response);
+        return;
+      }
+
+      // TODO: at this point we can access X-Weave-Timestamp, compare
+      // that to our local timestamp, and compute an estimate of clock
+      // skew. We can provide this to the incremental delegate, which
+      // will allow it to seamlessly correct timestamps on the records
+      // it processes. Bug 721887.
+
+      // Line-by-line processing, then invoke success.
+      SyncStorageCollectionRequestDelegate delegate = (SyncStorageCollectionRequestDelegate) this.request.delegate;
+      InputStream content = null;
+      BufferedReader br = null;
+      try {
+        content = entity.getContent();
+        br = new BufferedReader(new InputStreamReader(content), FETCH_BUFFER_SIZE);
+        String line;
+
+        // This relies on connection timeouts at the HTTP layer.
+        while (!aborting &&
+               null != (line = br.readLine())) {
+          try {
+            delegate.handleRequestProgress(line);
+          } catch (Exception ex) {
+            delegate.handleRequestError(new HandleProgressException(ex));
+            BaseResource.consumeEntity(entity);
+            return;
+          }
+        }
+        if (aborting) {
+          // So we don't hit the success case below.
+          return;
+        }
+      } catch (IOException ex) {
+        if (!aborting) {
+          delegate.handleRequestError(ex);
+        }
+        BaseResource.consumeEntity(entity);
+        return;
+      } finally {
+        // Attempt to close the stream and reader.
+        if (br != null) {
+          try {
+            br.close();
+          } catch (IOException e) {
+            // We don't care if this fails.
+          }
+        }
+      }
+      // We're done processing the entity. Don't let fetching the body succeed!
+      BaseResource.consumeEntity(entity);
+      delegate.handleRequestSuccess(new SyncStorageResponse(response));
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageCollectionRequestDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageCollectionRequestDelegate.java
new file mode 100644
index 000000000..ddf52007b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageCollectionRequestDelegate.java
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+public abstract class SyncStorageCollectionRequestDelegate implements
+    SyncStorageRequestIncrementalDelegate, SyncStorageRequestDelegate {
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRecordRequest.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRecordRequest.java
new file mode 100644
index 000000000..c18c4fe15
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRecordRequest.java
@@ -0,0 +1,95 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.sync.CryptoRecord;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.net.URISyntaxException;
+
+/**
+ * Resource class that implements expected headers and processing for Sync.
+ * Accepts a simplified delegate.
+ *
+ * Includes:
+ * * Basic Auth headers (via Resource)
+ * * Error responses:
+ *   * 401
+ *   * 503
+ * * Headers:
+ *   * Retry-After
+ *   * X-Weave-Backoff
+ *   * X-Backoff
+ *   * X-Weave-Records?
+ *   * ...
+ * * Timeouts
+ * * Network errors
+ * * application/newlines
+ * * JSON parsing
+ * * Content-Type and Content-Length validation.
+ */
+public class SyncStorageRecordRequest extends SyncStorageRequest {
+
+  public class SyncStorageRecordResourceDelegate extends SyncStorageResourceDelegate {
+    SyncStorageRecordResourceDelegate(SyncStorageRequest request) {
+      super(request);
+    }
+  }
+
+  public SyncStorageRecordRequest(URI uri) {
+    super(uri);
+  }
+
+  public SyncStorageRecordRequest(String url) throws URISyntaxException {
+    this(new URI(url));
+  }
+
+  @Override
+  protected BaseResourceDelegate makeResourceDelegate(SyncStorageRequest request) {
+    return new SyncStorageRecordResourceDelegate(request);
+  }
+
+  @SuppressWarnings("unchecked")
+  public void post(JSONObject body) {
+    // Let's do this the trivial way for now.
+    // Note that POSTs should be an array, so we wrap here.
+    final JSONArray toPOST = new JSONArray();
+    toPOST.add(body);
+    try {
+      this.resource.post(toPOST);
+    } catch (UnsupportedEncodingException e) {
+      this.delegate.handleRequestError(e);
+    }
+  }
+
+  public void post(JSONArray body) {
+    // Let's do this the trivial way for now.
+    try {
+      this.resource.post(body);
+    } catch (UnsupportedEncodingException e) {
+      this.delegate.handleRequestError(e);
+    }
+  }
+
+  public void put(JSONObject body) {
+    // Let's do this the trivial way for now.
+    try {
+      this.resource.put(body);
+    } catch (UnsupportedEncodingException e) {
+      this.delegate.handleRequestError(e);
+    }
+  }
+
+  public void post(CryptoRecord record) {
+    this.post(record.toJSONObject());
+  }
+
+  public void put(CryptoRecord record) {
+    this.put(record.toJSONObject());
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRequest.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRequest.java
new file mode 100644
index 000000000..3ede9cded
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRequest.java
@@ -0,0 +1,204 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.security.GeneralSecurityException;
+import java.util.HashMap;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.SyncConstants;
+
+import ch.boye.httpclientandroidlib.HttpEntity;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.ClientProtocolException;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+
+public class SyncStorageRequest implements Resource {
+  public static HashMap<String, String> SERVER_ERROR_MESSAGES;
+  static {
+    HashMap<String, String> errors = new HashMap<String, String>();
+
+    // Sync protocol errors.
+    errors.put("1", "Illegal method/protocol");
+    errors.put("2", "Incorrect/missing CAPTCHA");
+    errors.put("3", "Invalid/missing username");
+    errors.put("4", "Attempt to overwrite data that can't be overwritten (such as creating a user ID that already exists)");
+    errors.put("5", "User ID does not match account in path");
+    errors.put("6", "JSON parse failure");
+    errors.put("7", "Missing password field");
+    errors.put("8", "Invalid Weave Basic Object");
+    errors.put("9", "Requested password not strong enough");
+    errors.put("10", "Invalid/missing password reset code");
+    errors.put("11", "Unsupported function");
+    errors.put("12", "No email address on file");
+    errors.put("13", "Invalid collection");
+    errors.put("14", "User over quota");
+    errors.put("15", "The email does not match the username");
+    errors.put("16", "Client upgrade required");
+    errors.put("255", "An unexpected server error occurred: pool is empty.");
+
+    // Infrastructure-generated errors.
+    errors.put("\"server issue: getVS failed\"",                         "server issue: getVS failed");
+    errors.put("\"server issue: prefix not set\"",                       "server issue: prefix not set");
+    errors.put("\"server issue: host header not received from client\"", "server issue: host header not received from client");
+    errors.put("\"server issue: database lookup failed\"",               "server issue: database lookup failed");
+    errors.put("\"server issue: database is not healthy\"",              "server issue: database is not healthy");
+    errors.put("\"server issue: database not in pool\"",                 "server issue: database not in pool");
+    errors.put("\"server issue: database marked as down\"",              "server issue: database marked as down");
+    SERVER_ERROR_MESSAGES = errors;
+  }
+  public static String getServerErrorMessage(String body) {
+    if (SERVER_ERROR_MESSAGES.containsKey(body)) {
+      return SERVER_ERROR_MESSAGES.get(body);
+    }
+    return body;
+  }
+
+  /**
+   * @param uri
+   * @throws URISyntaxException
+   */
+  public SyncStorageRequest(String uri) throws URISyntaxException {
+    this(new URI(uri));
+  }
+
+  /**
+   * @param uri
+   */
+  public SyncStorageRequest(URI uri) {
+    this.resource = new BaseResource(uri);
+    this.resourceDelegate = this.makeResourceDelegate(this);
+    this.resource.delegate = this.resourceDelegate;
+  }
+
+  @Override
+  public URI getURI() {
+    return this.resource.getURI();
+  }
+
+  @Override
+  public String getURIString() {
+    return this.resource.getURIString();
+  }
+
+  @Override
+  public String getHostname() {
+    return this.resource.getHostname();
+  }
+
+  /**
+   * A ResourceDelegate that mediates between Resource-level notifications and the SyncStorageRequest.
+   */
+  public class SyncStorageResourceDelegate extends BaseResourceDelegate {
+    private static final String LOG_TAG = "SSResourceDelegate";
+    protected SyncStorageRequest request;
+
+    SyncStorageResourceDelegate(SyncStorageRequest request) {
+      super(request);
+      this.request = request;
+    }
+
+    @Override
+    public AuthHeaderProvider getAuthHeaderProvider() {
+      return request.delegate.getAuthHeaderProvider();
+    }
+
+    @Override
+    public String getUserAgent() {
+      return SyncConstants.USER_AGENT;
+    }
+
+    @Override
+    public void handleHttpResponse(HttpResponse response) {
+      Logger.debug(LOG_TAG, "SyncStorageResourceDelegate handling response: " + response.getStatusLine() + ".");
+      SyncStorageRequestDelegate d = this.request.delegate;
+      SyncStorageResponse res = new SyncStorageResponse(response);
+      // It is the responsibility of the delegate handlers to completely consume the response.
+      // In context of a Sync storage response, success is either a 200 OK or 202 Accepted.
+      // 202 is returned during uploads of data in a batching mode, indicating that more is expected.
+      if (res.getStatusCode() == 200 || res.getStatusCode() == 202) {
+        d.handleRequestSuccess(res);
+      } else {
+        Logger.warn(LOG_TAG, "HTTP request failed.");
+        try {
+          Logger.warn(LOG_TAG, "HTTP response body: " + res.getErrorMessage());
+        } catch (Exception e) {
+          Logger.error(LOG_TAG, "Can't fetch HTTP response body.", e);
+        }
+        d.handleRequestFailure(res);
+      }
+    }
+
+    @Override
+    public void handleHttpProtocolException(ClientProtocolException e) {
+      this.request.delegate.handleRequestError(e);
+    }
+
+    @Override
+    public void handleHttpIOException(IOException e) {
+      this.request.delegate.handleRequestError(e);
+    }
+
+    @Override
+    public void handleTransportException(GeneralSecurityException e) {
+      this.request.delegate.handleRequestError(e);
+    }
+
+    @Override
+    public void addHeaders(HttpRequestBase request, DefaultHttpClient client) {
+      // Clients can use their delegate interface to specify X-If-Unmodified-Since.
+      String ifUnmodifiedSince = this.request.delegate.ifUnmodifiedSince();
+      if (ifUnmodifiedSince != null) {
+        Logger.debug(LOG_TAG, "Making request with X-If-Unmodified-Since = " + ifUnmodifiedSince);
+        request.setHeader("x-if-unmodified-since", ifUnmodifiedSince);
+      }
+      if (request.getMethod().equalsIgnoreCase("DELETE")) {
+        request.addHeader("x-confirm-delete", "1");
+      }
+    }
+  }
+
+  protected BaseResourceDelegate resourceDelegate;
+  public SyncStorageRequestDelegate delegate;
+  protected BaseResource resource;
+
+  public SyncStorageRequest() {
+    super();
+  }
+
+  // Default implementation. Override this.
+  protected BaseResourceDelegate makeResourceDelegate(SyncStorageRequest request) {
+    return new SyncStorageResourceDelegate(request);
+  }
+
+  @Override
+  public void get() {
+    this.resource.get();
+  }
+
+  @Override
+  public void delete() {
+    this.resource.delete();
+  }
+
+  @Override
+  public void post(HttpEntity body) {
+    this.resource.post(body);
+  }
+
+  @Override
+  public void patch(HttpEntity body) {
+    this.resource.patch(body);
+  }
+
+  @Override
+  public void put(HttpEntity body) {
+    this.resource.put(body);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRequestDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRequestDelegate.java
new file mode 100644
index 000000000..29f42cc28
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRequestDelegate.java
@@ -0,0 +1,38 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+public interface SyncStorageRequestDelegate {
+  public AuthHeaderProvider getAuthHeaderProvider();
+
+  String ifUnmodifiedSince();
+
+  // TODO: at this point we can access X-Weave-Timestamp, compare
+  // that to our local timestamp, and compute an estimate of clock
+  // skew. Bug 721887.
+
+  /**
+   * Override this to handle a successful SyncStorageRequest.
+   *
+   * SyncStorageResourceDelegate implementers <b>must</b> ensure that the HTTP
+   * responses underlying SyncStorageResponses are fully consumed to ensure that
+   * connections are returned to the pool, for example by calling
+   * <code>BaseResource.consumeEntity(response)</code>.
+   */
+  void handleRequestSuccess(SyncStorageResponse response);
+
+  /**
+   * Override this to handle a failed SyncStorageRequest.
+   *
+   *
+   * SyncStorageResourceDelegate implementers <b>must</b> ensure that the HTTP
+   * responses underlying SyncStorageResponses are fully consumed to ensure that
+   * connections are returned to the pool, for example by calling
+   * <code>BaseResource.consumeEntity(response)</code>.
+   */
+  void handleRequestFailure(SyncStorageResponse response);
+
+  void handleRequestError(Exception ex);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRequestIncrementalDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRequestIncrementalDelegate.java
new file mode 100644
index 000000000..aa5d735bf
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageRequestIncrementalDelegate.java
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+public interface SyncStorageRequestIncrementalDelegate {
+  void handleRequestProgress(String progress);  // For line-by-line.
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageResponse.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageResponse.java
new file mode 100644
index 000000000..644df314c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/SyncStorageResponse.java
@@ -0,0 +1,85 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.io.IOException;
+import java.util.HashMap;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+
+public class SyncStorageResponse extends SyncResponse {
+  private static final String LOG_TAG = "SyncStorageResponse";
+
+  // Responses that are actionable get constant status codes.
+  public static final String RESPONSE_CLIENT_UPGRADE_REQUIRED = "16";
+
+  public static HashMap<String, String> SERVER_ERROR_MESSAGES;
+  static {
+    HashMap<String, String> errors = new HashMap<String, String>();
+
+    // Sync protocol errors.
+    errors.put("1", "Illegal method/protocol");
+    errors.put("2", "Incorrect/missing CAPTCHA");
+    errors.put("3", "Invalid/missing username");
+    errors.put("4", "Attempt to overwrite data that can't be overwritten (such as creating a user ID that already exists)");
+    errors.put("5", "User ID does not match account in path");
+    errors.put("6", "JSON parse failure");
+    errors.put("7", "Missing password field");
+    errors.put("8", "Invalid Weave Basic Object");
+    errors.put("9", "Requested password not strong enough");
+    errors.put("10", "Invalid/missing password reset code");
+    errors.put("11", "Unsupported function");
+    errors.put("12", "No email address on file");
+    errors.put("13", "Invalid collection");
+    errors.put("14", "User over quota");
+    errors.put("15", "The email does not match the username");
+    errors.put(RESPONSE_CLIENT_UPGRADE_REQUIRED, "Client upgrade required");
+    errors.put("255", "An unexpected server error occurred: pool is empty.");
+
+    // Infrastructure-generated errors.
+    errors.put("\"server issue: getVS failed\"",                         "server issue: getVS failed");
+    errors.put("\"server issue: prefix not set\"",                       "server issue: prefix not set");
+    errors.put("\"server issue: host header not received from client\"", "server issue: host header not received from client");
+    errors.put("\"server issue: database lookup failed\"",               "server issue: database lookup failed");
+    errors.put("\"server issue: database is not healthy\"",              "server issue: database is not healthy");
+    errors.put("\"server issue: database not in pool\"",                 "server issue: database not in pool");
+    errors.put("\"server issue: database marked as down\"",              "server issue: database marked as down");
+    SERVER_ERROR_MESSAGES = errors;
+  }
+  public static String getServerErrorMessage(String body) {
+    Logger.debug(LOG_TAG, "Looking up message for body \"" + body + "\"");
+    if (SERVER_ERROR_MESSAGES.containsKey(body)) {
+      return SERVER_ERROR_MESSAGES.get(body);
+    }
+    return body;
+  }
+
+
+  public SyncStorageResponse(HttpResponse res) {
+    super(res);
+  }
+
+  public String getErrorMessage() throws IllegalStateException, IOException {
+    return SyncStorageResponse.getServerErrorMessage(this.body().trim());
+  }
+
+  /**
+   * This header gives the last-modified time of the target resource as seen during processing of
+   * the request, and will be included in all success responses (200, 201, 204).
+   * When given in response to a write request, this will be equal to the server’s current time and
+   * to the new last-modified time of any BSOs created or changed by the request.
+   */
+  public String getLastModified() {
+    if (!response.containsHeader(X_LAST_MODIFIED)) {
+      return null;
+    }
+    return response.getFirstHeader(X_LAST_MODIFIED).getValue();
+  }
+
+  // TODO: Content-Type and Content-Length validation.
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/TLSSocketFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/TLSSocketFactory.java
new file mode 100644
index 000000000..dd68c0515
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/TLSSocketFactory.java
@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import java.io.IOException;
+import java.net.Socket;
+
+import javax.net.ssl.SSLContext;
+import javax.net.ssl.SSLSocket;
+
+import org.mozilla.gecko.background.common.GlobalConstants;
+import org.mozilla.gecko.background.common.log.Logger;
+
+import ch.boye.httpclientandroidlib.conn.ssl.SSLSocketFactory;
+import ch.boye.httpclientandroidlib.params.HttpParams;
+
+public class TLSSocketFactory extends SSLSocketFactory {
+  private static final String LOG_TAG = "TLSSocketFactory";
+
+  // Guarded by `this`.
+  private static String[] cipherSuites = GlobalConstants.DEFAULT_CIPHER_SUITES;
+
+  public TLSSocketFactory(SSLContext sslContext) {
+    super(sslContext);
+  }
+
+  /**
+   * Attempt to specify the cipher suites to use for a connection. If
+   * setting fails (as it will on Android 2.2, because the wrong names
+   * are in use to specify ciphers), attempt to set the defaults.
+   *
+   * We store the list of cipher suites in `cipherSuites`, which
+   * avoids this fallback handling having to be executed more than once.
+   *
+   * This method is synchronized to ensure correct use of that member.
+   *
+   * See Bug 717691 for more details.
+   *
+   * @param socket
+   *        The SSLSocket on which to operate.
+   */
+  public static synchronized void setEnabledCipherSuites(SSLSocket socket) {
+    try {
+      socket.setEnabledCipherSuites(cipherSuites);
+    } catch (IllegalArgumentException e) {
+      cipherSuites = socket.getSupportedCipherSuites();
+      Logger.warn(LOG_TAG, "Setting enabled cipher suites failed: " + e.getMessage());
+      Logger.warn(LOG_TAG, "Using " + cipherSuites.length + " supported suites.");
+      socket.setEnabledCipherSuites(cipherSuites);
+    }
+  }
+
+  @Override
+  public Socket createSocket(HttpParams params) throws IOException {
+    SSLSocket socket = (SSLSocket) super.createSocket(params);
+    socket.setEnabledProtocols(GlobalConstants.DEFAULT_PROTOCOLS);
+    setEnabledCipherSuites(socket);
+    return socket;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/WBOCollectionRequestDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/WBOCollectionRequestDelegate.java
new file mode 100644
index 000000000..2e26f041b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/WBOCollectionRequestDelegate.java
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.KeyBundleProvider;
+
+/**
+ * Subclass this to handle collection fetches.
+ * @author rnewman
+ *
+ */
+public abstract class WBOCollectionRequestDelegate
+extends SyncStorageCollectionRequestDelegate
+implements KeyBundleProvider {
+
+  @Override
+  public abstract KeyBundle keyBundle();
+  public abstract void handleWBO(CryptoRecord record);
+
+  @Override
+  public void handleRequestProgress(String progress) {
+    try {
+      CryptoRecord record = CryptoRecord.fromJSONRecord(progress);
+      record.keyBundle = this.keyBundle();
+      this.handleWBO(record);
+    } catch (Exception e) {
+      this.handleRequestError(e);
+      // TODO: abort?! Allow exception to propagate to fail?
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/WBORequestDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/WBORequestDelegate.java
new file mode 100644
index 000000000..8a09e0c7f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/WBORequestDelegate.java
@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.net;
+
+import org.mozilla.gecko.sync.KeyBundleProvider;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+
+public abstract class WBORequestDelegate
+implements SyncStorageRequestDelegate, KeyBundleProvider {
+  @Override
+  public abstract KeyBundle keyBundle();
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/BookmarkNeedsReparentingException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/BookmarkNeedsReparentingException.java
new file mode 100644
index 000000000..5fe3dc9fa
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/BookmarkNeedsReparentingException.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class BookmarkNeedsReparentingException extends SyncException {
+
+  private static final long serialVersionUID = -7018336108709392800L;
+
+  public BookmarkNeedsReparentingException(Exception ex) {
+    super(ex);
+  }
+
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/BookmarksRepository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/BookmarksRepository.java
new file mode 100644
index 000000000..289fc48ec
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/BookmarksRepository.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+/**
+ * Shared interface for repositories that consume and produce
+ * bookmark records.
+ *
+ * @author rnewman
+ *
+ */
+public interface BookmarksRepository {
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/ConstrainedServer11Repository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/ConstrainedServer11Repository.java
new file mode 100644
index 000000000..a6dc3f6b8
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/ConstrainedServer11Repository.java
@@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import java.net.URISyntaxException;
+
+import org.mozilla.gecko.sync.InfoCollections;
+import org.mozilla.gecko.sync.InfoConfiguration;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+
+/**
+ * A kind of Server11Repository that supports explicit setting of total fetch limit, per-batch fetch limit, and a sort order.
+ *
+ * @author rnewman
+ *
+ */
+public class ConstrainedServer11Repository extends Server11Repository {
+
+  private final String sort;
+  private final long batchLimit;
+  private final long totalLimit;
+
+  public ConstrainedServer11Repository(String collection, String storageURL,
+                                       AuthHeaderProvider authHeaderProvider,
+                                       InfoCollections infoCollections,
+                                       InfoConfiguration infoConfiguration,
+                                       long batchLimit, long totalLimit, String sort)
+          throws URISyntaxException {
+    super(collection, storageURL, authHeaderProvider, infoCollections, infoConfiguration);
+    this.batchLimit = batchLimit;
+    this.totalLimit = totalLimit;
+    this.sort  = sort;
+  }
+
+  @Override
+  public String getDefaultSort() {
+    return sort;
+  }
+
+  @Override
+  public long getDefaultBatchLimit() {
+    return batchLimit;
+  }
+
+  @Override
+  public long getDefaultTotalLimit() {
+    return totalLimit;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/FetchFailedException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/FetchFailedException.java
new file mode 100644
index 000000000..8b29a37ba
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/FetchFailedException.java
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class FetchFailedException extends SyncException {
+  private static final long serialVersionUID = -7533105300182522946L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/HashSetStoreTracker.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/HashSetStoreTracker.java
new file mode 100644
index 000000000..3b6facc31
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/HashSetStoreTracker.java
@@ -0,0 +1,61 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import java.util.HashSet;
+import java.util.Iterator;
+
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+public class HashSetStoreTracker implements StoreTracker {
+
+  // Guarded by `this`.
+  // Used to store GUIDs that were not locally modified but
+  // have been modified by a call to `store`, and thus
+  // should not be returned by a subsequent fetch.
+  private final HashSet<String> guids;
+
+  public HashSetStoreTracker() {
+    guids = new HashSet<String>();
+  }
+
+  @Override
+  public String toString() {
+    return "#<Tracker: " + guids.size() + " guids tracked.>";
+  }
+
+  @Override
+  public synchronized boolean trackRecordForExclusion(String guid) {
+    return (guid != null) && guids.add(guid);
+  }
+
+  @Override
+  public synchronized boolean isTrackedForExclusion(String guid) {
+    return (guid != null) && guids.contains(guid);
+  }
+
+  @Override
+  public synchronized boolean untrackStoredForExclusion(String guid) {
+    return (guid != null) && guids.remove(guid);
+  }
+
+  @Override
+  public RecordFilter getFilter() {
+    if (guids.size() == 0) {
+      return null;
+    }
+    return new RecordFilter() {
+      @Override
+      public boolean excludeRecord(Record r) {
+        return isTrackedForExclusion(r.guid);
+      }
+    };
+  }
+
+  @Override
+  public Iterator<String> recordsTrackedForExclusion() {
+    return this.guids.iterator();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/HistoryRepository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/HistoryRepository.java
new file mode 100644
index 000000000..eddc32102
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/HistoryRepository.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+/**
+ * Shared interface for repositories that consume and produce
+ * history records.
+ *
+ * @author rnewman
+ *
+ */
+public interface HistoryRepository {
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/IdentityRecordFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/IdentityRecordFactory.java
new file mode 100644
index 000000000..acedc66e2
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/IdentityRecordFactory.java
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+public class IdentityRecordFactory extends RecordFactory {
+
+  @Override
+  public Record createRecord(Record record) {
+    return record;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InactiveSessionException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InactiveSessionException.java
new file mode 100644
index 000000000..185f0d724
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InactiveSessionException.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class InactiveSessionException extends SyncException {
+
+  private static final long serialVersionUID = 537241160815940991L;
+
+  public InactiveSessionException(Exception ex) {
+    super(ex);
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InvalidBookmarkTypeException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InvalidBookmarkTypeException.java
new file mode 100644
index 000000000..3597276a4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InvalidBookmarkTypeException.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class InvalidBookmarkTypeException extends SyncException {
+
+  private static final long serialVersionUID = -6098516814844387449L;
+
+  public InvalidBookmarkTypeException(Exception e) {
+    super(e);
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InvalidRequestException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InvalidRequestException.java
new file mode 100644
index 000000000..3f761e540
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InvalidRequestException.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class InvalidRequestException extends SyncException {
+
+  private static final long serialVersionUID = 4502951350743608243L;
+
+  public InvalidRequestException(Exception ex) {
+    super(ex);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InvalidSessionTransitionException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InvalidSessionTransitionException.java
new file mode 100644
index 000000000..0963892c9
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/InvalidSessionTransitionException.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class InvalidSessionTransitionException extends SyncException {
+
+  private static final long serialVersionUID = 4157729859314427281L;
+
+  public InvalidSessionTransitionException(Exception ex) {
+    super(ex);
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/MultipleRecordsForGuidException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/MultipleRecordsForGuidException.java
new file mode 100644
index 000000000..58cca4a49
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/MultipleRecordsForGuidException.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class MultipleRecordsForGuidException extends SyncException {
+
+  private static final long serialVersionUID = 7426987323485324741L;
+
+  public MultipleRecordsForGuidException(Exception ex) {
+    super(ex);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NoContentProviderException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NoContentProviderException.java
new file mode 100644
index 000000000..85d119a5d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NoContentProviderException.java
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+import android.net.Uri;
+
+/**
+ * Raised when a Content Provider cannot be retrieved.
+ *
+ * @author rnewman
+ *
+ */
+public class NoContentProviderException extends SyncException {
+  private static final long serialVersionUID = 1L;
+
+  public final Uri requestedProvider;
+  public NoContentProviderException(Uri requested) {
+    super();
+    this.requestedProvider = requested;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NoGuidForIdException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NoGuidForIdException.java
new file mode 100644
index 000000000..3681deffd
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NoGuidForIdException.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class NoGuidForIdException extends SyncException {
+
+  private static final long serialVersionUID = -675614284405829041L;
+
+  public NoGuidForIdException(Exception ex) {
+    super(ex);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NoStoreDelegateException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NoStoreDelegateException.java
new file mode 100644
index 000000000..5747039aa
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NoStoreDelegateException.java
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class NoStoreDelegateException extends SyncException {
+  private static final long serialVersionUID = 6631689468978422074L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NullCursorException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NullCursorException.java
new file mode 100644
index 000000000..4d9057992
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/NullCursorException.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class NullCursorException extends SyncException {
+
+  private static final long serialVersionUID = 3146506225701104661L;
+
+  public NullCursorException(Exception e) {
+    super(e);
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/ParentNotFoundException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/ParentNotFoundException.java
new file mode 100644
index 000000000..991fd7426
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/ParentNotFoundException.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class ParentNotFoundException extends SyncException {
+  
+  private static final long serialVersionUID = -2687003621705922982L;
+
+  public ParentNotFoundException(Exception ex) {
+    super(ex);
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/ProfileDatabaseException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/ProfileDatabaseException.java
new file mode 100644
index 000000000..0f8075133
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/ProfileDatabaseException.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class ProfileDatabaseException extends SyncException {
+
+  private static final long serialVersionUID = -4916908502042261602L;
+
+  public ProfileDatabaseException(Exception ex) {
+    super(ex);
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RecordFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RecordFactory.java
new file mode 100644
index 000000000..6a8d81a77
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RecordFactory.java
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+// Take a record retrieved from some middleware, producing
+// some concrete record type for application to some local repository.
+public abstract class RecordFactory {
+  public abstract Record createRecord(Record record);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RecordFilter.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RecordFilter.java
new file mode 100644
index 000000000..733448ded
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RecordFilter.java
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+public interface RecordFilter {
+  public boolean excludeRecord(Record r);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/Repository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/Repository.java
new file mode 100644
index 000000000..3dd3fd2c4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/Repository.java
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCleanDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+
+import android.content.Context;
+
+public abstract class Repository {
+  public abstract void createSession(RepositorySessionCreationDelegate delegate, Context context);
+
+  public void clean(boolean success, RepositorySessionCleanDelegate delegate, Context context) {
+    delegate.onCleaned(this);
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RepositorySession.java
new file mode 100644
index 000000000..84fca1379
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RepositorySession.java
@@ -0,0 +1,384 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionBeginDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionGuidsSinceDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionStoreDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionWipeDelegate;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+/**
+ * A <code>RepositorySession</code> is created and used thusly:
+ *
+ *<ul>
+ * <li>Construct, with a reference to its parent {@link Repository}, by calling
+ *   {@link Repository#createSession(RepositorySessionCreationDelegate, android.content.Context)}.</li>
+ * <li>Populate with saved information by calling {@link #unbundle(RepositorySessionBundle)}.</li>
+ * <li>Begin a sync by calling {@link #begin(RepositorySessionBeginDelegate)}. <code>begin()</code>
+ *   is an appropriate place to initialize expensive resources.</li>
+ * <li>Perform operations such as {@link #fetchSince(long, RepositorySessionFetchRecordsDelegate)} and
+ *   {@link #store(Record)}.</li>
+ * <li>Finish by calling {@link #finish(RepositorySessionFinishDelegate)}, retrieving and storing
+ *   the current bundle.</li>
+ *</ul>
+ *
+ * If <code>finish()</code> is not called, {@link #abort()} must be called. These calls must
+ * <em>always</em> be paired with <code>begin()</code>.
+ *
+ */
+public abstract class RepositorySession {
+
+  public enum SessionStatus {
+    UNSTARTED,
+    ACTIVE,
+    ABORTED,
+    DONE
+  }
+
+  private static final String LOG_TAG = "RepositorySession";
+
+  protected static void trace(String message) {
+    Logger.trace(LOG_TAG, message);
+  }
+
+  private SessionStatus status = SessionStatus.UNSTARTED;
+  protected Repository repository;
+  protected RepositorySessionStoreDelegate delegate;
+
+  /**
+   * A queue of Runnables which call out into delegates.
+   */
+  protected ExecutorService delegateQueue  = Executors.newSingleThreadExecutor();
+
+  /**
+   * A queue of Runnables which effect storing.
+   * This includes actual store work, and also the consequences of storeDone.
+   * This provides strict ordering.
+   */
+  protected ExecutorService storeWorkQueue = Executors.newSingleThreadExecutor();
+
+  // The time that the last sync on this collection completed, in milliseconds since epoch.
+  private long lastSyncTimestamp = 0;
+
+  public long getLastSyncTimestamp() {
+    return lastSyncTimestamp;
+  }
+
+  public static long now() {
+    return System.currentTimeMillis();
+  }
+
+  public RepositorySession(Repository repository) {
+    this.repository = repository;
+  }
+
+  public abstract void guidsSince(long timestamp, RepositorySessionGuidsSinceDelegate delegate);
+  public abstract void fetchSince(long timestamp, RepositorySessionFetchRecordsDelegate delegate);
+  public abstract void fetch(String[] guids, RepositorySessionFetchRecordsDelegate delegate) throws InactiveSessionException;
+  public abstract void fetchAll(RepositorySessionFetchRecordsDelegate delegate);
+
+  /**
+   * Override this if you wish to short-circuit a sync when you know --
+   * e.g., by inspecting the database or info/collections -- that no new
+   * data are available.
+   *
+   * @return true if a sync should proceed.
+   */
+  public boolean dataAvailable() {
+    return true;
+  }
+
+  /**
+   * @return true if we cannot safely sync from this <code>RepositorySession</code>.
+   */
+  public boolean shouldSkip() {
+    return false;
+  }
+
+  /*
+   * Store operations proceed thusly:
+   *
+   * * Set a delegate
+   * * Store an arbitrary number of records. At any time the delegate can be
+   *   notified of an error.
+   * * Call storeDone to notify the session that no more items are forthcoming.
+   * * The store delegate will be notified of error or completion.
+   *
+   * This arrangement of calls allows for batching at the session level.
+   *
+   * Store success calls are not guaranteed.
+   */
+  public void setStoreDelegate(RepositorySessionStoreDelegate delegate) {
+    Logger.debug(LOG_TAG, "Setting store delegate to " + delegate);
+    this.delegate = delegate;
+  }
+  public abstract void store(Record record) throws NoStoreDelegateException;
+
+  public void storeDone() {
+    // Our default behavior will be to assume that the Runnable is
+    // executed as soon as all the stores synchronously finish, so
+    // our end timestamp can just be… now.
+    storeDone(now());
+  }
+
+  public void storeDone(final long end) {
+    Logger.debug(LOG_TAG, "Scheduling onStoreCompleted for after storing is done: " + end);
+    Runnable command = new Runnable() {
+      @Override
+      public void run() {
+        delegate.onStoreCompleted(end);
+      }
+    };
+    storeWorkQueue.execute(command);
+  }
+
+  public abstract void wipe(RepositorySessionWipeDelegate delegate);
+
+  /**
+   * Synchronously perform the shared work of beginning. Throws on failure.
+   * @throws InvalidSessionTransitionException
+   *
+   */
+  protected void sharedBegin() throws InvalidSessionTransitionException {
+    Logger.debug(LOG_TAG, "Shared begin.");
+    if (delegateQueue.isShutdown()) {
+      throw new InvalidSessionTransitionException(null);
+    }
+    if (storeWorkQueue.isShutdown()) {
+      throw new InvalidSessionTransitionException(null);
+    }
+    this.transitionFrom(SessionStatus.UNSTARTED, SessionStatus.ACTIVE);
+  }
+
+  /**
+   * Start the session. This is an appropriate place to initialize
+   * data access components such as database handles.
+   *
+   * @param delegate
+   * @throws InvalidSessionTransitionException
+   */
+  public void begin(RepositorySessionBeginDelegate delegate) throws InvalidSessionTransitionException {
+    sharedBegin();
+    delegate.deferredBeginDelegate(delegateQueue).onBeginSucceeded(this);
+  }
+
+  public void unbundle(RepositorySessionBundle bundle) {
+    this.lastSyncTimestamp = bundle == null ? 0 : bundle.getTimestamp();
+  }
+
+  /**
+   * Override this in your subclasses to return values to save between sessions.
+   * Note that RepositorySession automatically bumps the timestamp to the time
+   * the last sync began. If unbundled but not begun, this will be the same as the
+   * value in the input bundle.
+   *
+   * The Synchronizer most likely wants to bump the bundle timestamp to be a value
+   * return from a fetch call.
+   */
+  protected RepositorySessionBundle getBundle() {
+    // Why don't we just persist the old bundle?
+    long timestamp = getLastSyncTimestamp();
+    RepositorySessionBundle bundle = new RepositorySessionBundle(timestamp);
+    Logger.debug(LOG_TAG, "Setting bundle timestamp to " + timestamp + ".");
+
+    return bundle;
+  }
+
+  /**
+   * Just like finish(), but doesn't do any work that should only be performed
+   * at the end of a successful sync, and can be called any time.
+   */
+  public void abort(RepositorySessionFinishDelegate delegate) {
+    this.abort();
+    delegate.deferredFinishDelegate(delegateQueue).onFinishSucceeded(this, this.getBundle());
+  }
+
+  /**
+   * Abnormally terminate the repository session, freeing or closing
+   * any resources that were opened during the lifetime of the session.
+   */
+  public void abort() {
+    // TODO: do something here.
+    this.setStatus(SessionStatus.ABORTED);
+    try {
+      storeWorkQueue.shutdownNow();
+    } catch (Exception e) {
+      Logger.error(LOG_TAG, "Caught exception shutting down store work queue.", e);
+    }
+    try {
+      delegateQueue.shutdown();
+    } catch (Exception e) {
+      Logger.error(LOG_TAG, "Caught exception shutting down delegate queue.", e);
+    }
+  }
+
+  /**
+   * End the repository session, freeing or closing any resources
+   * that were opened during the lifetime of the session.
+   *
+   * @param delegate notified of success or failure.
+   * @throws InactiveSessionException
+   */
+  public void finish(final RepositorySessionFinishDelegate delegate) throws InactiveSessionException {
+    try {
+      this.transitionFrom(SessionStatus.ACTIVE, SessionStatus.DONE);
+      delegate.deferredFinishDelegate(delegateQueue).onFinishSucceeded(this, this.getBundle());
+    } catch (InvalidSessionTransitionException e) {
+      Logger.error(LOG_TAG, "Tried to finish() an unstarted or already finished session");
+      throw new InactiveSessionException(e);
+    }
+
+    Logger.trace(LOG_TAG, "Shutting down work queues.");
+    storeWorkQueue.shutdown();
+    delegateQueue.shutdown();
+  }
+
+  /**
+   * Run the provided command if we're active and our delegate queue
+   * is not shut down.
+   */
+  protected synchronized void executeDelegateCommand(Runnable command)
+      throws InactiveSessionException {
+    if (!isActive() || delegateQueue.isShutdown()) {
+      throw new InactiveSessionException(null);
+    }
+    delegateQueue.execute(command);
+  }
+
+  public synchronized void ensureActive() throws InactiveSessionException {
+    if (!isActive()) {
+      throw new InactiveSessionException(null);
+    }
+  }
+
+  public synchronized boolean isActive() {
+    return status == SessionStatus.ACTIVE;
+  }
+
+  public synchronized SessionStatus getStatus() {
+    return status;
+  }
+
+  public synchronized void setStatus(SessionStatus status) {
+    this.status = status;
+  }
+
+  public synchronized void transitionFrom(SessionStatus from, SessionStatus to) throws InvalidSessionTransitionException {
+    if (from == null || this.status == from) {
+      Logger.trace(LOG_TAG, "Successfully transitioning from " + this.status + " to " + to);
+
+      this.status = to;
+      return;
+    }
+    Logger.warn(LOG_TAG, "Wanted to transition from " + from + " but in state " + this.status);
+    throw new InvalidSessionTransitionException(null);
+  }
+
+  /**
+   * Produce a record that is some combination of the remote and local records
+   * provided.
+   *
+   * The returned record must be produced without mutating either remoteRecord
+   * or localRecord. It is acceptable to return either remoteRecord or localRecord
+   * if no modifications are to be propagated.
+   *
+   * The returned record *should* have the local androidID and the remote GUID,
+   * and some optional merge of data from the two records.
+   *
+   * This method can be called with records that are identical, or differ in
+   * any regard.
+   *
+   * This method will not be called if:
+   *
+   * * either record is marked as deleted, or
+   * * there is no local mapping for a new remote record.
+   *
+   * Otherwise, it will be called precisely once.
+   *
+   * Side-effects (e.g., for transactional storage) can be hooked in here.
+   *
+   * @param remoteRecord
+   *        The record retrieved from upstream, already adjusted for clock skew.
+   * @param localRecord
+   *        The record retrieved from local storage.
+   * @param lastRemoteRetrieval
+   *        The timestamp of the last retrieved set of remote records, adjusted for
+   *        clock skew.
+   * @param lastLocalRetrieval
+   *        The timestamp of the last retrieved set of local records.
+   * @return
+   *        A Record instance to apply, or null to apply nothing.
+   */
+  protected Record reconcileRecords(final Record remoteRecord,
+                                    final Record localRecord,
+                                    final long lastRemoteRetrieval,
+                                    final long lastLocalRetrieval) {
+    Logger.debug(LOG_TAG, "Reconciling remote " + remoteRecord.guid + " against local " + localRecord.guid);
+
+    if (localRecord.equalPayloads(remoteRecord)) {
+      if (remoteRecord.lastModified > localRecord.lastModified) {
+        Logger.debug(LOG_TAG, "Records are equal. No record application needed.");
+        return null;
+      }
+
+      // Local wins.
+      return null;
+    }
+
+    // TODO: Decide what to do based on:
+    // * Which of the two records is modified;
+    // * Whether they are equal or congruent;
+    // * The modified times of each record (interpreted through the lens of clock skew);
+    // * ...
+    boolean localIsMoreRecent = localRecord.lastModified > remoteRecord.lastModified;
+    Logger.debug(LOG_TAG, "Local record is more recent? " + localIsMoreRecent);
+    Record donor = localIsMoreRecent ? localRecord : remoteRecord;
+
+    // Modify the local record to match the remote record's GUID and values.
+    // Preserve the local Android ID, and merge data where possible.
+    // It sure would be nice if copyWithIDs didn't give a shit about androidID, mm?
+    Record out = donor.copyWithIDs(remoteRecord.guid, localRecord.androidID);
+
+    // We don't want to upload the record if the remote record was
+    // applied without changes.
+    // This logic will become more complicated as reconciling becomes smarter.
+    if (!localIsMoreRecent) {
+      trackGUID(out.guid);
+    }
+    return out;
+  }
+
+  /**
+   * Depending on the RepositorySession implementation, track
+   * that a record — most likely a brand-new record that has been
+   * applied unmodified — should be tracked so as to not be uploaded
+   * redundantly.
+   *
+   * The default implementations do nothing.
+   */
+  protected void trackGUID(String guid) {
+  }
+
+  protected synchronized void untrackGUIDs(Collection<String> guids) {
+  }
+
+  protected void untrackGUID(String guid) {
+  }
+
+  // Ah, Java. You wretched creature.
+  public Iterator<String> getTrackedRecordIDs() {
+    return new ArrayList<String>().iterator();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RepositorySessionBundle.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RepositorySessionBundle.java
new file mode 100644
index 000000000..7908ec797
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/RepositorySessionBundle.java
@@ -0,0 +1,55 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+
+import java.io.IOException;
+
+public class RepositorySessionBundle {
+  public static final String LOG_TAG = RepositorySessionBundle.class.getSimpleName();
+
+  protected static final String JSON_KEY_TIMESTAMP = "timestamp";
+
+  protected final ExtendedJSONObject object;
+
+  public RepositorySessionBundle(String jsonString) throws IOException, NonObjectJSONException {
+
+    object = new ExtendedJSONObject(jsonString);
+  }
+
+  public RepositorySessionBundle(long lastSyncTimestamp) {
+    object = new ExtendedJSONObject();
+    this.setTimestamp(lastSyncTimestamp);
+  }
+
+  public long getTimestamp() {
+    if (object.containsKey(JSON_KEY_TIMESTAMP)) {
+      return object.getLong(JSON_KEY_TIMESTAMP);
+    }
+
+    return -1;
+  }
+
+  public void setTimestamp(long timestamp) {
+    Logger.debug(LOG_TAG, "Setting timestamp to " + timestamp + ".");
+    object.put(JSON_KEY_TIMESTAMP, timestamp);
+  }
+
+  public void bumpTimestamp(long timestamp) {
+    long existing = this.getTimestamp();
+    if (timestamp > existing) {
+      this.setTimestamp(timestamp);
+    } else {
+      Logger.debug(LOG_TAG, "Timestamp " + timestamp + " not greater than " + existing + "; not bumping.");
+    }
+  }
+
+  public String toJSONString() {
+    return object.toJSONString();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/Server11Repository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/Server11Repository.java
new file mode 100644
index 000000000..4404fda25
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/Server11Repository.java
@@ -0,0 +1,144 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.ArrayList;
+
+import org.mozilla.gecko.sync.InfoCollections;
+import org.mozilla.gecko.sync.InfoConfiguration;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+
+/**
+ * A Server11Repository implements fetching and storing against the Sync 1.1 API.
+ * It doesn't do crypto: that's the job of the middleware.
+ *
+ * @author rnewman
+ */
+public class Server11Repository extends Repository {
+  protected String collection;
+  protected URI collectionURI;
+  protected final AuthHeaderProvider authHeaderProvider;
+  protected final InfoCollections infoCollections;
+
+  private final InfoConfiguration infoConfiguration;
+
+  /**
+   * Construct a new repository that fetches and stores against the Sync 1.1. API.
+   *
+   * @param collection name.
+   * @param storageURL full URL to storage endpoint.
+   * @param authHeaderProvider to use in requests; may be null.
+   * @param infoCollections instance; must not be null.
+   * @throws URISyntaxException
+   */
+  public Server11Repository(@NonNull String collection, @NonNull String storageURL, AuthHeaderProvider authHeaderProvider, @NonNull InfoCollections infoCollections, @NonNull InfoConfiguration infoConfiguration) throws URISyntaxException {
+    if (collection == null) {
+      throw new IllegalArgumentException("collection must not be null");
+    }
+    if (storageURL == null) {
+      throw new IllegalArgumentException("storageURL must not be null");
+    }
+    if (infoCollections == null) {
+      throw new IllegalArgumentException("infoCollections must not be null");
+    }
+    this.collection = collection;
+    this.collectionURI = new URI(storageURL + (storageURL.endsWith("/") ? collection : "/" + collection));
+    this.authHeaderProvider = authHeaderProvider;
+    this.infoCollections = infoCollections;
+    this.infoConfiguration = infoConfiguration;
+  }
+
+  @Override
+  public void createSession(RepositorySessionCreationDelegate delegate,
+                            Context context) {
+    delegate.onSessionCreated(new Server11RepositorySession(this));
+  }
+
+  public URI collectionURI() {
+    return this.collectionURI;
+  }
+
+  public URI collectionURI(boolean full, long newer, long limit, String sort, String ids, String offset) throws URISyntaxException {
+    ArrayList<String> params = new ArrayList<String>();
+    if (full) {
+      params.add("full=1");
+    }
+    if (newer >= 0) {
+      // Translate local millisecond timestamps into server decimal seconds.
+      String newerString = Utils.millisecondsToDecimalSecondsString(newer);
+      params.add("newer=" + newerString);
+    }
+    if (limit > 0) {
+      params.add("limit=" + limit);
+    }
+    if (sort != null) {
+      params.add("sort=" + sort);       // We trust these values.
+    }
+    if (ids != null) {
+      params.add("ids=" + ids);         // We trust these values.
+    }
+    if (offset != null) {
+      // Offset comes straight out of HTTP headers and it is the responsibility of the caller to URI-escape it.
+      params.add("offset=" + offset);
+    }
+    if (params.size() == 0) {
+      return this.collectionURI;
+    }
+
+    StringBuilder out = new StringBuilder();
+    char indicator = '?';
+    for (String param : params) {
+      out.append(indicator);
+      indicator = '&';
+      out.append(param);
+    }
+    String uri = this.collectionURI + out.toString();
+    return new URI(uri);
+  }
+
+  public URI wboURI(String id) throws URISyntaxException {
+    return new URI(this.collectionURI + "/" + id);
+  }
+
+  // Override these.
+  @SuppressWarnings("static-method")
+  public long getDefaultBatchLimit() {
+    return -1;
+  }
+
+  @SuppressWarnings("static-method")
+  public String getDefaultSort() {
+    return null;
+  }
+
+  public long getDefaultTotalLimit() {
+    return -1;
+  }
+
+  public AuthHeaderProvider getAuthHeaderProvider() {
+    return authHeaderProvider;
+  }
+
+  public boolean updateNeeded(long lastSyncTimestamp) {
+    return infoCollections.updateNeeded(collection, lastSyncTimestamp);
+  }
+
+  @Nullable
+  public Long getCollectionLastModified() {
+    return infoCollections.getTimestamp(collection);
+  }
+
+  public InfoConfiguration getInfoConfiguration() {
+    return infoConfiguration;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/Server11RepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/Server11RepositorySession.java
new file mode 100644
index 000000000..20c735a6b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/Server11RepositorySession.java
@@ -0,0 +1,104 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionGuidsSinceDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionStoreDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionWipeDelegate;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+import org.mozilla.gecko.sync.repositories.downloaders.BatchingDownloader;
+import org.mozilla.gecko.sync.repositories.uploaders.BatchingUploader;
+
+public class Server11RepositorySession extends RepositorySession {
+  public static final String LOG_TAG = "Server11Session";
+
+  Server11Repository serverRepository;
+  private BatchingUploader uploader;
+  private final BatchingDownloader downloader;
+
+  public Server11RepositorySession(Repository repository) {
+    super(repository);
+    serverRepository = (Server11Repository) repository;
+    this.downloader = new BatchingDownloader(serverRepository, this);
+  }
+
+  public Server11Repository getServerRepository() {
+    return serverRepository;
+  }
+
+  @Override
+  public void setStoreDelegate(RepositorySessionStoreDelegate delegate) {
+    this.delegate = delegate;
+
+    // Now that we have the delegate, we can initialize our uploader.
+    this.uploader = new BatchingUploader(this, storeWorkQueue, delegate);
+  }
+
+  @Override
+  public void guidsSince(long timestamp,
+                         RepositorySessionGuidsSinceDelegate delegate) {
+    // TODO Auto-generated method stub
+
+  }
+
+  @Override
+  public void fetchSince(long timestamp,
+                         RepositorySessionFetchRecordsDelegate delegate) {
+    this.downloader.fetchSince(timestamp, delegate);
+  }
+
+  @Override
+  public void fetchAll(RepositorySessionFetchRecordsDelegate delegate) {
+    this.fetchSince(-1, delegate);
+  }
+
+  @Override
+  public void fetch(String[] guids,
+                    RepositorySessionFetchRecordsDelegate delegate) {
+    this.downloader.fetch(guids, delegate);
+  }
+
+  @Override
+  public void wipe(RepositorySessionWipeDelegate delegate) {
+    if (!isActive()) {
+      delegate.onWipeFailed(new InactiveSessionException(null));
+      return;
+    }
+    // TODO: implement wipe.
+  }
+
+  @Override
+  public void store(Record record) throws NoStoreDelegateException {
+    if (delegate == null) {
+      throw new NoStoreDelegateException();
+    }
+
+    // If delegate was set, this shouldn't happen.
+    if (uploader == null) {
+      throw new IllegalStateException("Uploader haven't been initialized");
+    }
+
+    uploader.process(record);
+  }
+
+  @Override
+  public void storeDone() {
+    Logger.debug(LOG_TAG, "storeDone().");
+
+    // If delegate was set, this shouldn't happen.
+    if (uploader == null) {
+      throw new IllegalStateException("Uploader haven't been initialized");
+    }
+
+    uploader.noMoreRecordsToUpload();
+  }
+
+  @Override
+  public boolean dataAvailable() {
+    return serverRepository.updateNeeded(getLastSyncTimestamp());
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/StoreFailedException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/StoreFailedException.java
new file mode 100644
index 000000000..fcb09e32e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/StoreFailedException.java
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import org.mozilla.gecko.sync.SyncException;
+
+public class StoreFailedException extends SyncException {
+  private static final long serialVersionUID = 6080340122855859752L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/StoreTracker.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/StoreTracker.java
new file mode 100644
index 000000000..b6a3071a9
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/StoreTracker.java
@@ -0,0 +1,82 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import java.util.Iterator;
+
+/**
+ * Our hacky version of transactional semantics. The goal is to prevent
+ * the following situation:
+ *
+ * * AAA is not modified locally.
+ * * A modified AAA is downloaded during the storing phase. Its local
+ *   timestamp is advanced.
+ * * The direction of syncing changes, and AAA is now uploaded to the server.
+ *
+ * The following situation should still be supported:
+ *
+ * * AAA is not modified locally.
+ * * A modified AAA is downloaded and merged with the local AAA.
+ * * The merged AAA is uploaded to the server.
+ *
+ * As should:
+ *
+ * * AAA is modified locally.
+ * * A modified AAA is downloaded, and discarded or merged.
+ * * The current version of AAA is uploaded to the server.
+ *
+ * We achieve this by tracking GUIDs during the storing phase. If we
+ * apply a record such that the local copy is substantially the same
+ * as the record we just downloaded, we add it to a list of records
+ * to avoid uploading. The definition of "substantially the same"
+ * depends on the particular repository. The only consideration is "do we
+ * want to upload this record in this sync?".
+ *
+ * Note that items are removed from this list when a fetch that
+ * considers them for upload completes successfully. The entire list
+ * is discarded when the session is completed.
+ *
+ * This interface exposes methods to:
+ *
+ * * During a store, recording that a record has been stored, and should
+ *   thus not be returned in subsequent fetches;
+ * * During a fetch, checking whether a record should be returned.
+ *
+ * In the future this might also grow self-persistence.
+ *
+ * See also RepositorySession.trackRecord.
+ *
+ * @author rnewman
+ *
+ */
+public interface StoreTracker {
+
+  /**
+   * @param guid
+   *        The GUID of the item to track.
+   * @return
+   *        Whether the GUID was a newly tracked value.
+   */
+  public boolean trackRecordForExclusion(String guid);
+
+  /**
+   * @param guid
+   *        The GUID of the item to check.
+   * @return
+   *        true if the item is already tracked.
+   */
+  public boolean isTrackedForExclusion(String guid);
+
+  /**
+  *
+  * @param guid
+  * @return true if the specified GUID was removed from the tracked set.
+  */
+  public boolean untrackStoredForExclusion(String guid);
+
+  public RecordFilter getFilter();
+
+  public Iterator<String> recordsTrackedForExclusion();
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/StoreTrackingRepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/StoreTrackingRepositorySession.java
new file mode 100644
index 000000000..1a5c1e96a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/StoreTrackingRepositorySession.java
@@ -0,0 +1,102 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories;
+
+import java.util.Collection;
+import java.util.Iterator;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionBeginDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+public abstract class StoreTrackingRepositorySession extends RepositorySession {
+  private static final String LOG_TAG = "StoreTrackSession";
+  protected StoreTracker storeTracker;
+
+  protected static StoreTracker createStoreTracker() {
+    return new HashSetStoreTracker();
+  }
+
+  public StoreTrackingRepositorySession(Repository repository) {
+    super(repository);
+  }
+
+  @Override
+  public void begin(RepositorySessionBeginDelegate delegate) throws InvalidSessionTransitionException {
+    RepositorySessionBeginDelegate deferredDelegate = delegate.deferredBeginDelegate(delegateQueue);
+    try {
+      super.sharedBegin();
+    } catch (InvalidSessionTransitionException e) {
+      deferredDelegate.onBeginFailed(e);
+      return;
+    }
+    // Or do this in your own subclass.
+    storeTracker = createStoreTracker();
+    deferredDelegate.onBeginSucceeded(this);
+  }
+
+  @Override
+  protected synchronized void trackGUID(String guid) {
+    if (this.storeTracker == null) {
+      throw new IllegalStateException("Store tracker not yet initialized!");
+    }
+    this.storeTracker.trackRecordForExclusion(guid);
+  }
+
+  @Override
+  protected synchronized void untrackGUID(String guid) {
+    if (this.storeTracker == null) {
+      throw new IllegalStateException("Store tracker not yet initialized!");
+    }
+    this.storeTracker.untrackStoredForExclusion(guid);
+  }
+
+  @Override
+  protected synchronized void untrackGUIDs(Collection<String> guids) {
+    if (this.storeTracker == null) {
+      throw new IllegalStateException("Store tracker not yet initialized!");
+    }
+    if (guids == null) {
+      return;
+    }
+    for (String guid : guids) {
+      this.storeTracker.untrackStoredForExclusion(guid);
+    }
+  }
+
+  protected void trackRecord(Record record) {
+
+    Logger.debug(LOG_TAG, "Tracking record " + record.guid +
+                           " (" + record.lastModified + ") to avoid re-upload.");
+    // Future: we care about the timestamp…
+    trackGUID(record.guid);
+  }
+
+  protected void untrackRecord(Record record) {
+    Logger.debug(LOG_TAG, "Un-tracking record " + record.guid + ".");
+    untrackGUID(record.guid);
+  }
+
+  @Override
+  public Iterator<String> getTrackedRecordIDs() {
+    if (this.storeTracker == null) {
+      throw new IllegalStateException("Store tracker not yet initialized!");
+    }
+    return this.storeTracker.recordsTrackedForExclusion();
+  }
+
+  @Override
+  public void abort(RepositorySessionFinishDelegate delegate) {
+    this.storeTracker = null;
+    super.abort(delegate);
+  }
+
+  @Override
+  public void finish(RepositorySessionFinishDelegate delegate) throws InactiveSessionException {
+    super.finish(delegate);
+    this.storeTracker = null;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserBookmarksDataAccessor.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserBookmarksDataAccessor.java
new file mode 100644
index 000000000..fd3c35da0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserBookmarksDataAccessor.java
@@ -0,0 +1,326 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.json.simple.JSONArray;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.domain.BookmarkRecord;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+
+public class AndroidBrowserBookmarksDataAccessor extends AndroidBrowserRepositoryDataAccessor {
+
+  private static final String LOG_TAG = "BookmarksDataAccessor";
+
+  /*
+   * Fragments of SQL to make our lives easier.
+   */
+  private static final String BOOKMARK_IS_FOLDER = BrowserContract.Bookmarks.TYPE + " = " +
+                                                   BrowserContract.Bookmarks.TYPE_FOLDER;
+
+  // SQL fragment to retrieve GUIDs whose ID mappings should be tracked by this session.
+  // Exclude folders we don't want to sync.
+  private static final String GUID_SHOULD_TRACK = BrowserContract.SyncColumns.GUID + " NOT IN ('" +
+                                                  BrowserContract.Bookmarks.TAGS_FOLDER_GUID + "', '" +
+                                                  BrowserContract.Bookmarks.PLACES_FOLDER_GUID + "', '" +
+                                                  BrowserContract.Bookmarks.PINNED_FOLDER_GUID + "')";
+
+  private static final String EXCLUDE_SPECIAL_GUIDS_WHERE_CLAUSE;
+  static {
+    if (AndroidBrowserBookmarksRepositorySession.SPECIAL_GUIDS.length > 0) {
+      StringBuilder b = new StringBuilder(BrowserContract.SyncColumns.GUID + " NOT IN (");
+
+      int remaining = AndroidBrowserBookmarksRepositorySession.SPECIAL_GUIDS.length - 1;
+      for (String specialGuid : AndroidBrowserBookmarksRepositorySession.SPECIAL_GUIDS) {
+        b.append('"');
+        b.append(specialGuid);
+        b.append('"');
+        if (remaining-- > 0) {
+          b.append(", ");
+        }
+      }
+      b.append(')');
+      EXCLUDE_SPECIAL_GUIDS_WHERE_CLAUSE = b.toString();
+    } else {
+      EXCLUDE_SPECIAL_GUIDS_WHERE_CLAUSE = null;       // null is a valid WHERE clause.
+    }
+  }
+
+  public static final String TYPE_FOLDER = "folder";
+  public static final String TYPE_BOOKMARK = "bookmark";
+
+  private final RepoUtils.QueryHelper queryHelper;
+
+  public AndroidBrowserBookmarksDataAccessor(Context context) {
+    super(context);
+    this.queryHelper = new RepoUtils.QueryHelper(context, getUri(), LOG_TAG);
+  }
+
+  @Override
+  protected Uri getUri() {
+    return BrowserContractHelpers.BOOKMARKS_CONTENT_URI;
+  }
+
+  protected static Uri getPositionsUri() {
+    return BrowserContractHelpers.BOOKMARKS_POSITIONS_CONTENT_URI;
+  }
+
+  @Override
+  public void wipe() {
+    Uri uri = getUri();
+    Logger.info(LOG_TAG, "wiping (except for special guids): " + uri);
+    context.getContentResolver().delete(uri, EXCLUDE_SPECIAL_GUIDS_WHERE_CLAUSE, null);
+  }
+
+  private final String[] GUID_AND_ID = new String[] { BrowserContract.Bookmarks.GUID,
+                                                BrowserContract.Bookmarks._ID };
+
+  protected Cursor getGuidsIDsForFolders() throws NullCursorException {
+    // Exclude items that we don't want to sync (pinned items, reading list, 
+    // tags, the places root), in case they've ended up in the DB.
+    String where = BOOKMARK_IS_FOLDER + " AND " + GUID_SHOULD_TRACK;
+    return queryHelper.safeQuery(".getGuidsIDsForFolders", GUID_AND_ID, where, null, null);
+  }
+
+  /**
+   * Issue a request to the Content Provider to update the positions of the
+   * records named by the provided GUIDs to the index of their GUID in the
+   * provided array.
+   *
+   * @param childArray
+   *        A sequence of GUID strings.
+   */
+  public int updatePositions(ArrayList<String> childArray) {
+    final int size = childArray.size();
+    if (size == 0) {
+      return 0;
+    }
+
+    Logger.debug(LOG_TAG, "Updating positions for " + size + " items.");
+    String[] args = childArray.toArray(new String[size]);
+    return context.getContentResolver().update(getPositionsUri(), new ContentValues(), null, args);
+  }
+
+  public int bumpModifiedByGUID(Collection<String> ids, long modified) {
+    final int size = ids.size();
+    if (size == 0) {
+      return 0;
+    }
+
+    Logger.debug(LOG_TAG, "Bumping modified for " + size + " items to " + modified);
+    String where = RepoUtils.computeSQLInClause(size, BrowserContract.Bookmarks.GUID);
+    String[] selectionArgs = ids.toArray(new String[size]);
+    ContentValues values = new ContentValues();
+    values.put(BrowserContract.Bookmarks.DATE_MODIFIED, modified);
+
+    return context.getContentResolver().update(getUri(), values, where, selectionArgs);
+  }
+
+  /**
+   * Bump the modified time of a record by ID.
+   */
+  public int bumpModified(long id, long modified) {
+    Logger.debug(LOG_TAG, "Bumping modified for " + id + " to " + modified);
+    String where = BrowserContract.Bookmarks._ID + " = ?";
+    String[] selectionArgs = new String[] { String.valueOf(id) };
+    ContentValues values = new ContentValues();
+    values.put(BrowserContract.Bookmarks.DATE_MODIFIED, modified);
+
+    return context.getContentResolver().update(getUri(), values, where, selectionArgs);
+  }
+
+  protected void updateParentAndPosition(String guid, long newParentId, long position) {
+    ContentValues cv = new ContentValues();
+    cv.put(BrowserContract.Bookmarks.PARENT, newParentId);
+    if (position >= 0) {
+      cv.put(BrowserContract.Bookmarks.POSITION, position);
+    }
+    updateByGuid(guid, cv);
+  }
+
+  protected Map<String, Long> idsForGUIDs(String[] guids) throws NullCursorException {
+    final String where = RepoUtils.computeSQLInClause(guids.length, BrowserContract.Bookmarks.GUID);
+    Cursor c = queryHelper.safeQuery(".idsForGUIDs", GUID_AND_ID, where, guids, null);
+    try {
+      HashMap<String, Long> out = new HashMap<String, Long>();
+      if (!c.moveToFirst()) {
+        return out;
+      }
+      final int guidIndex = c.getColumnIndexOrThrow(BrowserContract.Bookmarks.GUID);
+      final int idIndex = c.getColumnIndexOrThrow(BrowserContract.Bookmarks._ID);
+      while (!c.isAfterLast()) {
+        out.put(c.getString(guidIndex), c.getLong(idIndex));
+        c.moveToNext();
+      }
+      return out;
+    } finally {
+      c.close();
+    }
+  }
+
+  /**
+   * Move the children of each source folder to the destination folder.
+   * Bump the modified time of each child.
+   * The caller should bump the modified time of the destination if desired.
+   *
+   * @param fromIDs the Android IDs of the source folders.
+   * @param to the Android ID of the destination folder.
+   * @return the number of updated rows.
+   */
+  protected int moveChildren(String[] fromIDs, long to) {
+    long now = System.currentTimeMillis();
+    long pos = -1;
+
+    ContentValues cv = new ContentValues();
+    cv.put(BrowserContract.Bookmarks.PARENT, to);
+    cv.put(BrowserContract.Bookmarks.DATE_MODIFIED, now);
+    cv.put(BrowserContract.Bookmarks.POSITION, pos);
+
+    final String where = RepoUtils.computeSQLInClause(fromIDs.length, BrowserContract.Bookmarks.PARENT);
+    return context.getContentResolver().update(getUri(), cv, where, fromIDs);
+  }
+  
+  /*
+   * Verify that all special GUIDs are present and that they aren't marked as deleted.
+   * Insert them if they aren't there.
+   */
+  public void checkAndBuildSpecialGuids() throws NullCursorException {
+    final String[] specialGUIDs = AndroidBrowserBookmarksRepositorySession.SPECIAL_GUIDS;
+    Cursor cur = fetch(specialGUIDs);
+    long placesRoot = 0;
+
+    // Map from GUID to whether deleted. Non-presence implies just that.
+    HashMap<String, Boolean> statuses = new HashMap<String, Boolean>(specialGUIDs.length);
+    try {
+      if (cur.moveToFirst()) {
+        while (!cur.isAfterLast()) {
+          String guid = RepoUtils.getStringFromCursor(cur, BrowserContract.SyncColumns.GUID);
+          if ("places".equals(guid)) {
+            placesRoot = RepoUtils.getLongFromCursor(cur, BrowserContract.CommonColumns._ID);
+          }
+          // Make sure none of these folders are marked as deleted.
+          boolean deleted = RepoUtils.getLongFromCursor(cur, BrowserContract.SyncColumns.IS_DELETED) == 1;
+          statuses.put(guid, deleted);
+          cur.moveToNext();
+        }
+      }
+    } finally {
+      cur.close();
+    }
+
+    // Insert or undelete them if missing.
+    for (String guid : specialGUIDs) {
+      if (statuses.containsKey(guid)) {
+        if (statuses.get(guid)) {
+          // Undelete.
+          Logger.info(LOG_TAG, "Undeleting special GUID " + guid);
+          ContentValues cv = new ContentValues();
+          cv.put(BrowserContract.SyncColumns.IS_DELETED, 0);
+          updateByGuid(guid, cv);
+        }
+      } else {
+        // Insert.
+        if (guid.equals("places")) {
+          // This is awkward.
+          Logger.info(LOG_TAG, "No places root. Inserting one.");
+          placesRoot = insertSpecialFolder("places", 0);
+        } else if (guid.equals("mobile")) {
+          Logger.info(LOG_TAG, "No mobile folder. Inserting one under the places root.");
+          insertSpecialFolder("mobile", placesRoot);
+        } else {
+          // unfiled, menu, toolbar.
+          Logger.info(LOG_TAG, "No " + guid + " root. Inserting one under places (" + placesRoot + ").");
+          insertSpecialFolder(guid, placesRoot);
+        }
+      }
+    }
+  }
+
+  private long insertSpecialFolder(String guid, long parentId) {
+    BookmarkRecord record = new BookmarkRecord(guid);
+    record.title = AndroidBrowserBookmarksRepositorySession.SPECIAL_GUIDS_MAP.get(guid);
+    record.type = "folder";
+    record.androidParentID = parentId;
+    return ContentUris.parseId(insert(record));
+  }
+
+  @Override
+  protected ContentValues getContentValues(Record record) {
+    BookmarkRecord rec = (BookmarkRecord) record;
+
+    if (rec.deleted) {
+      ContentValues cv = new ContentValues();
+      cv.put(BrowserContract.SyncColumns.GUID,     rec.guid);
+      cv.put(BrowserContract.Bookmarks.IS_DELETED, 1);
+      return cv;
+    }
+
+    final int recordType = BrowserContractHelpers.typeCodeForString(rec.type);
+    if (recordType == -1) {
+      throw new IllegalStateException("Unexpected record type " + rec.type);
+    }
+
+    ContentValues cv = new ContentValues();
+    cv.put(BrowserContract.SyncColumns.GUID,      rec.guid);
+    cv.put(BrowserContract.Bookmarks.TYPE,        recordType);
+    cv.put(BrowserContract.Bookmarks.TITLE,       rec.title);
+    cv.put(BrowserContract.Bookmarks.URL,         rec.bookmarkURI);
+    cv.put(BrowserContract.Bookmarks.DESCRIPTION, rec.description);
+    if (rec.tags == null) {
+      rec.tags = new JSONArray();
+    }
+    cv.put(BrowserContract.Bookmarks.TAGS,        rec.tags.toJSONString());
+    cv.put(BrowserContract.Bookmarks.KEYWORD,     rec.keyword);
+    cv.put(BrowserContract.Bookmarks.PARENT,      rec.androidParentID);
+    cv.put(BrowserContract.Bookmarks.POSITION,    rec.androidPosition);
+
+    // Note that we don't set the modified timestamp: we allow the
+    // content provider to do that for us.
+    return cv;
+  }
+
+  /**
+   * Returns a cursor over non-deleted records that list the given androidID as a parent.
+   */
+  public Cursor getChildren(long androidID) throws NullCursorException {
+    return getChildren(androidID, false);
+  }
+
+  /**
+   * Returns a cursor with any records that list the given androidID as a parent.
+   * Excludes 'places', and optionally any deleted records.
+   */
+  public Cursor getChildren(long androidID, boolean includeDeleted) throws NullCursorException {
+    final String where = BrowserContract.Bookmarks.PARENT + " = ? AND " +
+                         BrowserContract.SyncColumns.GUID + " <> ? " +
+                         (!includeDeleted ? ("AND " + BrowserContract.SyncColumns.IS_DELETED + " = 0") : "");
+
+    final String[] args = new String[] { String.valueOf(androidID), "places" };
+
+    // Order by position, falling back on creation date and ID.
+    final String order = BrowserContract.Bookmarks.POSITION + ", " +
+                         BrowserContract.SyncColumns.DATE_CREATED + ", " +
+                         BrowserContract.Bookmarks._ID;
+    return queryHelper.safeQuery(".getChildren", getAllColumns(), where, args, order);
+  }
+
+  
+  @Override
+  protected String[] getAllColumns() {
+    return BrowserContractHelpers.BookmarkColumns;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserBookmarksRepository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserBookmarksRepository.java
new file mode 100644
index 000000000..38520fd7a
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserBookmarksRepository.java
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import org.mozilla.gecko.sync.repositories.BookmarksRepository;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+
+import android.content.Context;
+
+public class AndroidBrowserBookmarksRepository extends AndroidBrowserRepository implements BookmarksRepository {
+
+  @Override
+  protected void sessionCreator(RepositorySessionCreationDelegate delegate, Context context) {
+    AndroidBrowserBookmarksRepositorySession session = new AndroidBrowserBookmarksRepositorySession(AndroidBrowserBookmarksRepository.this, context);
+    final RepositorySessionCreationDelegate deferredCreationDelegate = delegate.deferredCreationDelegate();
+    deferredCreationDelegate.onSessionCreated(session);
+  }
+
+  @Override
+  protected AndroidBrowserRepositoryDataAccessor getDataAccessor(Context context) {
+    return new AndroidBrowserBookmarksDataAccessor(context);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserBookmarksRepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserBookmarksRepositorySession.java
new file mode 100644
index 000000000..fb79901a1
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserBookmarksRepositorySession.java
@@ -0,0 +1,1107 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.TreeMap;
+
+import org.json.simple.JSONArray;
+import org.mozilla.gecko.R;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.repositories.InactiveSessionException;
+import org.mozilla.gecko.sync.repositories.InvalidSessionTransitionException;
+import org.mozilla.gecko.sync.repositories.NoGuidForIdException;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.ParentNotFoundException;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionBeginDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionStoreDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionWipeDelegate;
+import org.mozilla.gecko.sync.repositories.domain.BookmarkRecord;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+import android.content.ContentUris;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+
+public class AndroidBrowserBookmarksRepositorySession extends AndroidBrowserRepositorySession
+  implements BookmarksInsertionManager.BookmarkInserter {
+
+  public static final int DEFAULT_DELETION_FLUSH_THRESHOLD = 50;
+  public static final int DEFAULT_INSERTION_FLUSH_THRESHOLD = 50;
+
+  // TODO: synchronization for these.
+  private final HashMap<String, Long> parentGuidToIDMap = new HashMap<String, Long>();
+  private final HashMap<Long, String> parentIDToGuidMap = new HashMap<Long, String>();
+
+  /**
+   * Some notes on reparenting/reordering.
+   *
+   * Fennec stores new items with a high-negative position, because it doesn't care.
+   * On the other hand, it also doesn't give us any help managing positions.
+   *
+   * We can process records and folders in any order, though we'll usually see folders
+   * first because their sortindex is larger.
+   *
+   * We can also see folders that refer to children we haven't seen, and children we
+   * won't see (perhaps due to a TTL, perhaps due to a limit on our fetch).
+   *
+   * And of course folders can refer to local children (including ones that might
+   * be reconciled into oblivion!), or local children in other folders. And the local
+   * version of a folder -- which might be a reconciling target, or might not -- can
+   * have local additions or removals. (That causes complications with on-the-fly
+   * reordering: we don't know in advance which records will even exist by the end
+   * of the sync.)
+   *
+   * We opt to leave records in a reasonable state as we go, applying reordering/
+   * reparenting operations whenever possible. A final sequence is applied after all
+   * incoming records have been handled.
+   *
+   * As such, we need to track a bunch of stuff as we go:
+   *
+   * • For each downloaded folder, the array of children. These will be server GUIDs,
+   *   but not necessarily identical to the remote list: if we download a record and
+   *   it's been locally moved, it must be removed from this child array.
+   *
+   *   This mapping can be discarded when final reordering has occurred, either on
+   *   store completion or when every child has been seen within this session.
+   *
+   * • A list of orphans: records whose parent folder does not yet exist. This can be
+   *   trimmed as orphans are reparented.
+   *
+   * • Mappings from folder GUIDs to folder IDs, so that we can parent items without
+   *   having to look in the DB. Of course, this must be kept up-to-date as we
+   *   reconcile.
+   *
+   * Reordering also needs to occur during fetch. That is, a folder might have been
+   * created locally, or modified locally without any remote changes. An order must
+   * be generated for the folder's children array, and it must be persisted into the
+   * database to act as a starting point for future changes. But of course we don't
+   * want to incur a database write if the children already have a satisfactory order.
+   *
+   * Do we also need a list of "adopters", parents that are still waiting for children?
+   * As items get picked out of the orphans list, we can do on-the-fly ordering, until
+   * we're left with lonely records at the end.
+   *
+   * As we modify local folders, perhaps by moving children out of their purview, we
+   * must bump their modification time so as to cause them to be uploaded on the next
+   * stage of syncing. The same applies to simple reordering.
+   */
+
+  // TODO: can we guarantee serial access to these?
+  private final HashMap<String, ArrayList<String>> missingParentToChildren = new HashMap<String, ArrayList<String>>();
+  private final HashMap<String, JSONArray>         parentToChildArray      = new HashMap<String, JSONArray>();
+  private int needsReparenting = 0;
+
+  private final AndroidBrowserBookmarksDataAccessor dataAccessor;
+
+  protected BookmarksDeletionManager deletionManager;
+  protected BookmarksInsertionManager insertionManager;
+
+  /**
+   * An array of known-special GUIDs.
+   */
+  public static final String[] SPECIAL_GUIDS = new String[] {
+    // Mobile and desktop places roots have to come first.
+    "places",
+    "mobile",
+    "toolbar",
+    "menu",
+    "unfiled"
+  };
+
+  /**
+   * = A note about folder mapping =
+   *
+   * Note that _none_ of Places's folders actually have a special GUID. They're all
+   * randomly generated. Special folders are indicated by membership in the
+   * moz_bookmarks_roots table, and by having the parent `1`.
+   *
+   * Additionally, the mobile root is annotated. In Firefox Sync, PlacesUtils is
+   * used to find the IDs of these special folders.
+   *
+   * We need to consume records with these various GUIDs, producing a local
+   * representation which we are able to stably map upstream.
+   *
+   * Android Sync skips over the contents of some special GUIDs -- `places`, `tags`,
+   * etc. -- when finding IDs.
+   * Some of these special GUIDs are part of desktop structure (places, tags). Some
+   * are part of Fennec's custom data (readinglist, pinned).
+   *
+   * We don't want to upload or apply these records.
+   *
+   * That is:
+   *
+   * * We should not upload a `places`,`tags`, `readinglist`, or `pinned` record.
+   * * We can stably _store_ menu/toolbar/unfiled/mobile as special GUIDs, and set
+     * their parent ID as appropriate on upload.
+   *
+   * Fortunately, Fennec stores our representation of the data, not Places: that is,
+   * there's a "places" root, containing "mobile", "menu", "toolbar", etc.
+   *
+   * These are guaranteed to exist when the database is created.
+   *
+   * = Places folders =
+   *
+   * guid        root_name   folder_id   parent
+   * ----------  ----------  ----------  ----------
+   * ?           places      1           0
+   * ?           menu        2           1
+   * ?           toolbar     3           1
+   * ?           tags        4           1
+   * ?           unfiled     5           1
+   *
+   * ?           mobile*     474         1
+   *
+   *
+   * = Fennec folders =
+   *
+   * guid        folder_id   parent
+   * ----------  ----------  ----------
+   * places      0           0
+   * mobile      1           0
+   * menu        2           0
+   * etc.
+   *
+  */
+  public static final Map<String, String> SPECIAL_GUID_PARENTS;
+  static {
+    HashMap<String, String> m = new HashMap<String, String>();
+    m.put("places",  null);
+    m.put("menu",    "places");
+    m.put("toolbar", "places");
+    m.put("tags",    "places");
+    m.put("unfiled", "places");
+    m.put("mobile",  "places");
+    SPECIAL_GUID_PARENTS = Collections.unmodifiableMap(m);
+  }
+
+
+  /**
+   * A map of guids to their localized name strings.
+   */
+  // Oh, if only we could make this final and initialize it in the static initializer.
+  public static Map<String, String> SPECIAL_GUIDS_MAP;
+
+  /**
+   * Return true if the provided record GUID should be skipped
+   * in child lists or fetch results.
+   *
+   * @param recordGUID the GUID of the record to check.
+   * @return true if the record should be skipped.
+   */
+  public static boolean forbiddenGUID(final String recordGUID) {
+    return recordGUID == null ||
+           BrowserContract.Bookmarks.PINNED_FOLDER_GUID.equals(recordGUID) ||
+           BrowserContract.Bookmarks.PLACES_FOLDER_GUID.equals(recordGUID) ||
+           BrowserContract.Bookmarks.TAGS_FOLDER_GUID.equals(recordGUID);
+  }
+
+  /**
+   * Return true if the provided parent GUID's children should
+   * be skipped in child lists or fetch results.
+   * This differs from {@link #forbiddenGUID(String)} in that we're skipping
+   * part of the hierarchy.
+   *
+   * @param parentGUID the GUID of parent of the record to check.
+   * @return true if the record should be skipped.
+   */
+  public static boolean forbiddenParent(final String parentGUID) {
+    return parentGUID == null ||
+           BrowserContract.Bookmarks.PINNED_FOLDER_GUID.equals(parentGUID);
+  }
+
+  public AndroidBrowserBookmarksRepositorySession(Repository repository, Context context) {
+    super(repository);
+
+    if (SPECIAL_GUIDS_MAP == null) {
+      HashMap<String, String> m = new HashMap<String, String>();
+
+      // Note that we always use the literal name "mobile" for the Mobile Bookmarks
+      // folder, regardless of its actual name in the database or the Fennec UI.
+      // This is to match desktop (working around Bug 747699) and to avoid a similar
+      // issue locally. See Bug 748898.
+      m.put("mobile",  "mobile");
+
+      // Other folders use their contextualized names, and we simply rely on
+      // these not changing, matching desktop, and such to avoid issues.
+      m.put("menu",    context.getString(R.string.bookmarks_folder_menu));
+      m.put("places",  context.getString(R.string.bookmarks_folder_places));
+      m.put("toolbar", context.getString(R.string.bookmarks_folder_toolbar));
+      m.put("unfiled", context.getString(R.string.bookmarks_folder_unfiled));
+
+      SPECIAL_GUIDS_MAP = Collections.unmodifiableMap(m);
+    }
+
+    dbHelper = new AndroidBrowserBookmarksDataAccessor(context);
+    dataAccessor = (AndroidBrowserBookmarksDataAccessor) dbHelper;
+  }
+
+  private static int getTypeFromCursor(Cursor cur) {
+    return RepoUtils.getIntFromCursor(cur, BrowserContract.Bookmarks.TYPE);
+  }
+
+  private static boolean rowIsFolder(Cursor cur) {
+    return getTypeFromCursor(cur) == BrowserContract.Bookmarks.TYPE_FOLDER;
+  }
+
+  private String getGUIDForID(long androidID) {
+    String guid = parentIDToGuidMap.get(androidID);
+    trace("  " + androidID + " => " + guid);
+    return guid;
+  }
+
+  private long getIDForGUID(String guid) {
+    Long id = parentGuidToIDMap.get(guid);
+    if (id == null) {
+      Logger.warn(LOG_TAG, "Couldn't find local ID for GUID " + guid);
+      return -1;
+    }
+    return id;
+  }
+
+  private String getGUID(Cursor cur) {
+    return RepoUtils.getStringFromCursor(cur, "guid");
+  }
+
+  private long getParentID(Cursor cur) {
+    return RepoUtils.getLongFromCursor(cur, BrowserContract.Bookmarks.PARENT);
+  }
+
+  // More efficient for bulk operations.
+  private long getPosition(Cursor cur, int positionIndex) {
+    return cur.getLong(positionIndex);
+  }
+  private long getPosition(Cursor cur) {
+    return RepoUtils.getLongFromCursor(cur, BrowserContract.Bookmarks.POSITION);
+  }
+
+  private String getParentName(String parentGUID) throws ParentNotFoundException, NullCursorException {
+    if (parentGUID == null) {
+      return "";
+    }
+    if (SPECIAL_GUIDS_MAP.containsKey(parentGUID)) {
+      return SPECIAL_GUIDS_MAP.get(parentGUID);
+    }
+
+    // Get parent name from database.
+    String parentName = "";
+    Cursor name = dataAccessor.fetch(new String[] { parentGUID });
+    try {
+      name.moveToFirst();
+      if (!name.isAfterLast()) {
+        parentName = RepoUtils.getStringFromCursor(name, BrowserContract.Bookmarks.TITLE);
+      }
+      else {
+        Logger.error(LOG_TAG, "Couldn't find record with guid '" + parentGUID + "' when looking for parent name.");
+        throw new ParentNotFoundException(null);
+      }
+    } finally {
+      name.close();
+    }
+    return parentName;
+  }
+
+  /**
+   * Retrieve the child array for a record, repositioning and updating the database as necessary.
+   *
+   * @param folderID
+   *        The database ID of the folder.
+   * @param persist
+   *        True if generated positions should be written to the database. The modified
+   *        time of the parent folder is only bumped if this is true.
+   * @param childArray
+   *        A new, empty JSONArray which will be populated with an array of GUIDs.
+   * @return
+   *        True if the resulting array is "clean" (i.e., reflects the content of the database).
+   * @throws NullCursorException
+   */
+  @SuppressWarnings("unchecked")
+  private boolean getChildrenArray(long folderID, boolean persist, JSONArray childArray) throws NullCursorException {
+    trace("Calling getChildren for androidID " + folderID);
+    Cursor children = dataAccessor.getChildren(folderID);
+    try {
+      if (!children.moveToFirst()) {
+        trace("No children: empty cursor.");
+        return true;
+      }
+      final int positionIndex = children.getColumnIndex(BrowserContract.Bookmarks.POSITION);
+      final int count = children.getCount();
+      Logger.debug(LOG_TAG, "Expecting " + count + " children.");
+
+      // Sorted by requested position.
+      TreeMap<Long, ArrayList<String>> guids = new TreeMap<Long, ArrayList<String>>();
+
+      while (!children.isAfterLast()) {
+        final String childGuid   = getGUID(children);
+        final long childPosition = getPosition(children, positionIndex);
+        trace("  Child GUID: " + childGuid);
+        trace("  Child position: " + childPosition);
+        Utils.addToIndexBucketMap(guids, Math.abs(childPosition), childGuid);
+        children.moveToNext();
+      }
+
+      // This will suffice for taking a jumble of records and indices and
+      // producing a sorted sequence that preserves some kind of order --
+      // from the abs of the position, falling back on cursor order (that
+      // is, creation time and ID).
+      // Note that this code is not intended to merge values from two sources!
+      boolean changed = false;
+      int i = 0;
+      for (Entry<Long, ArrayList<String>> entry : guids.entrySet()) {
+        long pos = entry.getKey();
+        int atPos = entry.getValue().size();
+
+        // If every element has a different index, and the indices are
+        // in strict natural order, then changed will be false.
+        if (atPos > 1 || pos != i) {
+          changed = true;
+        }
+
+        ++i;
+
+        for (String guid : entry.getValue()) {
+          if (!forbiddenGUID(guid)) {
+            childArray.add(guid);
+          }
+        }
+      }
+
+      if (Logger.shouldLogVerbose(LOG_TAG)) {
+        // Don't JSON-encode unless we're logging.
+        Logger.trace(LOG_TAG, "Output child array: " + childArray.toJSONString());
+      }
+
+      if (!changed) {
+        Logger.debug(LOG_TAG, "Nothing moved! Database reflects child array.");
+        return true;
+      }
+
+      if (!persist) {
+        Logger.debug(LOG_TAG, "Returned array does not match database, and not persisting.");
+        return false;
+      }
+
+      Logger.debug(LOG_TAG, "Generating child array required moving records. Updating DB.");
+      final long time = now();
+      if (0 < dataAccessor.updatePositions(childArray)) {
+        Logger.debug(LOG_TAG, "Bumping parent time to " + time + ".");
+        dataAccessor.bumpModified(folderID, time);
+      }
+      return true;
+    } finally {
+      children.close();
+    }
+  }
+
+  protected static boolean isDeleted(Cursor cur) {
+    return RepoUtils.getLongFromCursor(cur, BrowserContract.SyncColumns.IS_DELETED) != 0;
+  }
+
+  @Override
+  protected Record retrieveDuringStore(Cursor cur) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    // During storing of a retrieved record, we never care about the children
+    // array that's already present in the database -- we don't use it for
+    // reconciling. Skip all that effort for now.
+    return retrieveRecord(cur, false);
+  }
+
+  @Override
+  protected Record retrieveDuringFetch(Cursor cur) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    return retrieveRecord(cur, true);
+  }
+
+  /**
+   * Build a record from a cursor, with a flag to dictate whether the
+   * children array should be computed and written back into the database.
+   */
+  protected BookmarkRecord retrieveRecord(Cursor cur, boolean computeAndPersistChildren) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    String recordGUID = getGUID(cur);
+    Logger.trace(LOG_TAG, "Record from mirror cursor: " + recordGUID);
+
+    if (forbiddenGUID(recordGUID)) {
+      Logger.debug(LOG_TAG, "Ignoring " + recordGUID + " record in recordFromMirrorCursor.");
+      return null;
+    }
+
+    // Short-cut for deleted items.
+    if (isDeleted(cur)) {
+      return AndroidBrowserBookmarksRepositorySession.bookmarkFromMirrorCursor(cur, null, null, null);
+    }
+
+    long androidParentID = getParentID(cur);
+
+    // Ensure special folders stay in the right place.
+    String androidParentGUID = SPECIAL_GUID_PARENTS.get(recordGUID);
+    if (androidParentGUID == null) {
+      androidParentGUID = getGUIDForID(androidParentID);
+    }
+
+    boolean needsReparenting = false;
+
+    if (androidParentGUID == null) {
+      Logger.debug(LOG_TAG, "No parent GUID for record " + recordGUID + " with parent " + androidParentID);
+      // If the parent has been stored and somehow has a null GUID, throw an error.
+      if (parentIDToGuidMap.containsKey(androidParentID)) {
+        Logger.error(LOG_TAG, "Have the parent android ID for the record but the parent's GUID wasn't found.");
+        throw new NoGuidForIdException(null);
+      }
+
+      // We have a parent ID but it's wrong. If the record is deleted,
+      // we'll just say that it was in the Unsorted Bookmarks folder.
+      // If not, we'll move it into Mobile Bookmarks.
+      needsReparenting = true;
+    }
+
+    // If record is a folder, and we want to see children at this time, then build out the children array.
+    final JSONArray childArray;
+    if (computeAndPersistChildren) {
+      childArray = getChildrenArrayForRecordCursor(cur, recordGUID, true);
+    } else {
+      childArray = null;
+    }
+    String parentName = getParentName(androidParentGUID);
+    BookmarkRecord bookmark = AndroidBrowserBookmarksRepositorySession.bookmarkFromMirrorCursor(cur, androidParentGUID, parentName, childArray);
+
+    if (bookmark == null) {
+      Logger.warn(LOG_TAG, "Unable to extract bookmark from cursor. Record GUID " + recordGUID +
+                           ", parent " + androidParentGUID + "/" + androidParentID);
+      return null;
+    }
+
+    if (needsReparenting) {
+      Logger.warn(LOG_TAG, "Bookmark record " + recordGUID + " has a bad parent pointer. Reparenting now.");
+
+      String destination = bookmark.deleted ? "unfiled" : "mobile";
+      bookmark.androidParentID = getIDForGUID(destination);
+      bookmark.androidPosition = getPosition(cur);
+      bookmark.parentID        = destination;
+      bookmark.parentName      = getParentName(destination);
+      if (!bookmark.deleted) {
+        // Actually move it.
+        // TODO: compute position. Persist.
+        relocateBookmark(bookmark);
+      }
+    }
+
+    return bookmark;
+  }
+
+  /**
+   * Ensure that the local database row for the provided bookmark
+   * reflects this record's parent information.
+   *
+   * @param bookmark
+   */
+  private void relocateBookmark(BookmarkRecord bookmark) {
+    dataAccessor.updateParentAndPosition(bookmark.guid, bookmark.androidParentID, bookmark.androidPosition);
+  }
+
+  protected JSONArray getChildrenArrayForRecordCursor(Cursor cur, String recordGUID, boolean persist) throws NullCursorException {
+    boolean isFolder = rowIsFolder(cur);
+    if (!isFolder) {
+      return null;
+    }
+
+    long androidID = parentGuidToIDMap.get(recordGUID);
+    JSONArray childArray = new JSONArray();
+    getChildrenArray(androidID, persist, childArray);
+
+    Logger.debug(LOG_TAG, "Fetched " + childArray.size() + " children for " + recordGUID);
+    return childArray;
+  }
+
+  @Override
+  public boolean shouldIgnore(Record record) {
+    if (!(record instanceof BookmarkRecord)) {
+      return true;
+    }
+    if (record.deleted) {
+      return false;
+    }
+
+    BookmarkRecord bmk = (BookmarkRecord) record;
+
+    if (forbiddenGUID(bmk.guid)) {
+      Logger.debug(LOG_TAG, "Ignoring forbidden record with guid: " + bmk.guid);
+      return true;
+    }
+
+    if (forbiddenParent(bmk.parentID)) {
+      Logger.debug(LOG_TAG,  "Ignoring child " + bmk.guid + " of forbidden parent folder " + bmk.parentID);
+      return true;
+    }
+
+    if (BrowserContractHelpers.isSupportedType(bmk.type)) {
+      return false;
+    }
+
+    Logger.debug(LOG_TAG, "Ignoring record with guid: " + bmk.guid + " and type: " + bmk.type);
+    return true;
+  }
+
+  @Override
+  public void begin(RepositorySessionBeginDelegate delegate) throws InvalidSessionTransitionException {
+    // Check for the existence of special folders
+    // and insert them if they don't exist.
+    Cursor cur;
+    try {
+      Logger.debug(LOG_TAG, "Check and build special GUIDs.");
+      dataAccessor.checkAndBuildSpecialGuids();
+      cur = dataAccessor.getGuidsIDsForFolders();
+      Logger.debug(LOG_TAG, "Got GUIDs for folders.");
+    } catch (android.database.sqlite.SQLiteConstraintException e) {
+      Logger.error(LOG_TAG, "Got sqlite constraint exception working with Fennec bookmark DB.", e);
+      delegate.onBeginFailed(e);
+      return;
+    } catch (Exception e) {
+      delegate.onBeginFailed(e);
+      return;
+    }
+
+    // To deal with parent mapping of bookmarks we have to do some
+    // hairy stuff. Here's the setup for it.
+
+    Logger.debug(LOG_TAG, "Preparing folder ID mappings.");
+
+    // Fake our root.
+    Logger.debug(LOG_TAG, "Tracking places root as ID 0.");
+    parentIDToGuidMap.put(0L, "places");
+    parentGuidToIDMap.put("places", 0L);
+    try {
+      cur.moveToFirst();
+      while (!cur.isAfterLast()) {
+        String guid = getGUID(cur);
+        long id = RepoUtils.getLongFromCursor(cur, BrowserContract.Bookmarks._ID);
+        parentGuidToIDMap.put(guid, id);
+        parentIDToGuidMap.put(id, guid);
+        Logger.debug(LOG_TAG, "GUID " + guid + " maps to " + id);
+        cur.moveToNext();
+      }
+    } finally {
+      cur.close();
+    }
+    deletionManager = new BookmarksDeletionManager(dataAccessor, DEFAULT_DELETION_FLUSH_THRESHOLD);
+
+    // We just crawled the database enumerating all folders; we'll start the
+    // insertion manager with exactly these folders as the known parents (the
+    // collection is copied) in the manager constructor.
+    insertionManager = new BookmarksInsertionManager(DEFAULT_INSERTION_FLUSH_THRESHOLD, parentGuidToIDMap.keySet(), this);
+
+    Logger.debug(LOG_TAG, "Done with initial setup of bookmarks session.");
+    super.begin(delegate);
+  }
+
+  /**
+   * Implement method of BookmarksInsertionManager.BookmarkInserter.
+   */
+  @Override
+  public boolean insertFolder(BookmarkRecord record) {
+    // A folder that is *not* deleted needs its androidID updated, so that
+    // updateBookkeeping can re-parent, etc.
+    Record toStore = prepareRecord(record);
+    try {
+      Uri recordURI = dbHelper.insert(toStore);
+      if (recordURI == null) {
+        delegate.onRecordStoreFailed(new RuntimeException("Got null URI inserting folder with guid " + toStore.guid + "."), record.guid);
+        return false;
+      }
+      toStore.androidID = ContentUris.parseId(recordURI);
+      Logger.debug(LOG_TAG, "Inserted folder with guid " + toStore.guid + " as androidID " + toStore.androidID);
+
+      updateBookkeeping(toStore);
+    } catch (Exception e) {
+      delegate.onRecordStoreFailed(e, record.guid);
+      return false;
+    }
+    trackRecord(toStore);
+    delegate.onRecordStoreSucceeded(record.guid);
+    return true;
+  }
+
+  /**
+   * Implement method of BookmarksInsertionManager.BookmarkInserter.
+   */
+  @Override
+  public void bulkInsertNonFolders(Collection<BookmarkRecord> records) {
+    // All of these records are *not* deleted and *not* folders, so we don't
+    // need to update androidID at all!
+    // TODO: persist records that fail to insert for later retry.
+    ArrayList<Record> toStores = new ArrayList<Record>(records.size());
+    for (Record record : records) {
+      toStores.add(prepareRecord(record));
+    }
+
+    try {
+      int stored = dataAccessor.bulkInsert(toStores);
+      if (stored != toStores.size()) {
+        // Something failed; most pessimistic action is to declare that all insertions failed.
+        // TODO: perform the bulkInsert in a transaction and rollback unless all insertions succeed?
+        for (Record failed : toStores) {
+          delegate.onRecordStoreFailed(new RuntimeException("Possibly failed to bulkInsert non-folder with guid " + failed.guid + "."), failed.guid);
+        }
+        return;
+      }
+    } catch (NullCursorException e) {
+      for (Record failed : toStores) {
+        delegate.onRecordStoreFailed(e, failed.guid);
+      }
+      return;
+    }
+
+    // Success For All!
+    for (Record succeeded : toStores) {
+      try {
+        updateBookkeeping(succeeded);
+      } catch (Exception e) {
+        Logger.warn(LOG_TAG, "Got exception updating bookkeeping of non-folder with guid " + succeeded.guid + ".", e);
+      }
+      trackRecord(succeeded);
+      delegate.onRecordStoreSucceeded(succeeded.guid);
+    }
+  }
+
+  @Override
+  public void finish(RepositorySessionFinishDelegate delegate) throws InactiveSessionException {
+    // Allow these to be GCed.
+    deletionManager = null;
+    insertionManager = null;
+
+    // Override finish to do this check; make sure all records
+    // needing re-parenting have been re-parented.
+    if (needsReparenting != 0) {
+      Logger.error(LOG_TAG, "Finish called but " + needsReparenting +
+                            " bookmark(s) have been placed in unsorted bookmarks and not been reparented.");
+
+      // TODO: handling of failed reparenting.
+      // E.g., delegate.onFinishFailed(new BookmarkNeedsReparentingException(null));
+    }
+    super.finish(delegate);
+  };
+
+  @Override
+  public void setStoreDelegate(RepositorySessionStoreDelegate delegate) {
+    super.setStoreDelegate(delegate);
+
+    if (deletionManager != null) {
+      deletionManager.setDelegate(delegate);
+    }
+  }
+
+  @Override
+  protected Record reconcileRecords(Record remoteRecord, Record localRecord,
+                                    long lastRemoteRetrieval,
+                                    long lastLocalRetrieval) {
+
+    BookmarkRecord reconciled = (BookmarkRecord) super.reconcileRecords(remoteRecord, localRecord,
+                                                                        lastRemoteRetrieval,
+                                                                        lastLocalRetrieval);
+
+    // For now we *always* use the remote record's children array as a starting point.
+    // We won't write it into the database yet; we'll record it and process as we go.
+    reconciled.children = ((BookmarkRecord) remoteRecord).children;
+
+    // *Always* track folders, though: if we decide we need to reposition items, we'll
+    // untrack later.
+    if (reconciled.isFolder()) {
+      trackRecord(reconciled);
+    }
+    return reconciled;
+  }
+
+  /**
+   * Rename mobile folders to "mobile", both in and out. The other half of
+   * this logic lives in {@link #computeParentFields(BookmarkRecord, String, String)}, where
+   * the parent name of a record is set from {@link #SPECIAL_GUIDS_MAP} rather than
+   * from source data.
+   *
+   * Apply this approach generally for symmetry.
+   */
+  @Override
+  protected void fixupRecord(Record record) {
+    final BookmarkRecord r = (BookmarkRecord) record;
+    final String parentName = SPECIAL_GUIDS_MAP.get(r.parentID);
+    if (parentName == null) {
+      return;
+    }
+    if (Logger.shouldLogVerbose(LOG_TAG)) {
+      Logger.trace(LOG_TAG, "Replacing parent name \"" + r.parentName + "\" with \"" + parentName + "\".");
+    }
+    r.parentName = parentName;
+  }
+
+  @Override
+  protected Record prepareRecord(Record record) {
+    if (record.deleted) {
+      Logger.debug(LOG_TAG, "No need to prepare deleted record " + record.guid);
+      return record;
+    }
+
+    BookmarkRecord bmk = (BookmarkRecord) record;
+
+    if (!isSpecialRecord(record)) {
+      // We never want to reparent special records.
+      handleParenting(bmk);
+    }
+
+    if (Logger.LOG_PERSONAL_INFORMATION) {
+      if (bmk.isFolder()) {
+        Logger.pii(LOG_TAG, "Inserting folder " + bmk.guid + ", " + bmk.title +
+                            " with parent " + bmk.androidParentID +
+                            " (" + bmk.parentID + ", " + bmk.parentName +
+                            ", " + bmk.androidPosition + ")");
+      } else {
+        Logger.pii(LOG_TAG, "Inserting bookmark " + bmk.guid + ", " + bmk.title + ", " +
+                            bmk.bookmarkURI + " with parent " + bmk.androidParentID +
+                            " (" + bmk.parentID + ", " + bmk.parentName +
+                            ", " + bmk.androidPosition + ")");
+      }
+    } else {
+      if (bmk.isFolder()) {
+        Logger.debug(LOG_TAG, "Inserting folder " + bmk.guid +  ", parent " +
+                              bmk.androidParentID +
+                              " (" + bmk.parentID + ", " + bmk.androidPosition + ")");
+      } else {
+        Logger.debug(LOG_TAG, "Inserting bookmark " + bmk.guid + " with parent " +
+                              bmk.androidParentID +
+                              " (" + bmk.parentID + ", " + ", " + bmk.androidPosition + ")");
+      }
+    }
+    return bmk;
+  }
+
+  /**
+   * If the provided record doesn't have correct parent information,
+   * update appropriate bookkeeping to improve the situation.
+   *
+   * @param bmk
+   */
+  private void handleParenting(BookmarkRecord bmk) {
+    if (parentGuidToIDMap.containsKey(bmk.parentID)) {
+      bmk.androidParentID = parentGuidToIDMap.get(bmk.parentID);
+
+      // Might as well set a basic position from the downloaded children array.
+      JSONArray children = parentToChildArray.get(bmk.parentID);
+      if (children != null) {
+        int index = children.indexOf(bmk.guid);
+        if (index >= 0) {
+          bmk.androidPosition = index;
+        }
+      }
+    }
+    else {
+      bmk.androidParentID = parentGuidToIDMap.get("unfiled");
+      ArrayList<String> children;
+      if (missingParentToChildren.containsKey(bmk.parentID)) {
+        children = missingParentToChildren.get(bmk.parentID);
+      } else {
+        children = new ArrayList<String>();
+      }
+      children.add(bmk.guid);
+      needsReparenting++;
+      missingParentToChildren.put(bmk.parentID, children);
+    }
+  }
+
+  private boolean isSpecialRecord(Record record) {
+    return SPECIAL_GUID_PARENTS.containsKey(record.guid);
+  }
+
+  @Override
+  protected void updateBookkeeping(Record record) throws NoGuidForIdException,
+                                                         NullCursorException,
+                                                         ParentNotFoundException {
+    super.updateBookkeeping(record);
+    BookmarkRecord bmk = (BookmarkRecord) record;
+
+    // If record is folder, update maps and re-parent children if necessary.
+    if (!bmk.isFolder()) {
+      Logger.debug(LOG_TAG, "Not a folder. No bookkeeping.");
+      return;
+    }
+
+    Logger.debug(LOG_TAG, "Updating bookkeeping for folder " + record.guid);
+
+    // Mappings between ID and GUID.
+    // TODO: update our persisted children arrays!
+    // TODO: if our Android ID just changed, replace parents for all of our children.
+    parentGuidToIDMap.put(bmk.guid,      bmk.androidID);
+    parentIDToGuidMap.put(bmk.androidID, bmk.guid);
+
+    JSONArray childArray = bmk.children;
+
+    if (Logger.shouldLogVerbose(LOG_TAG)) {
+      Logger.trace(LOG_TAG, bmk.guid + " has children " + childArray.toJSONString());
+    }
+    parentToChildArray.put(bmk.guid, childArray);
+
+    // Re-parent.
+    if (missingParentToChildren.containsKey(bmk.guid)) {
+      for (String child : missingParentToChildren.get(bmk.guid)) {
+        // This might return -1; that's OK, the bookmark will
+        // be properly repositioned later.
+        long position = childArray.indexOf(child);
+        dataAccessor.updateParentAndPosition(child, bmk.androidID, position);
+        needsReparenting--;
+      }
+      missingParentToChildren.remove(bmk.guid);
+    }
+  }
+
+  @Override
+  protected void insert(Record record) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    try {
+      insertionManager.enqueueRecord((BookmarkRecord) record);
+    } catch (Exception e) {
+      throw new NullCursorException(e);
+    }
+  }
+
+  @Override
+  protected void storeRecordDeletion(final Record record, final Record existingRecord) {
+    if (SPECIAL_GUIDS_MAP.containsKey(record.guid)) {
+      Logger.debug(LOG_TAG, "Told to delete record " + record.guid + ". Ignoring.");
+      return;
+    }
+    final BookmarkRecord bookmarkRecord = (BookmarkRecord) record;
+    final BookmarkRecord existingBookmark = (BookmarkRecord) existingRecord;
+    final boolean isFolder = existingBookmark.isFolder();
+    final String parentGUID = existingBookmark.parentID;
+    deletionManager.deleteRecord(bookmarkRecord.guid, isFolder, parentGUID);
+  }
+
+  protected void flushQueues() {
+    long now = now();
+    Logger.debug(LOG_TAG, "Applying remaining insertions.");
+    try {
+      insertionManager.finishUp();
+      Logger.debug(LOG_TAG, "Done applying remaining insertions.");
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Unable to apply remaining insertions.", e);
+    }
+
+    Logger.debug(LOG_TAG, "Applying deletions.");
+    try {
+      untrackGUIDs(deletionManager.flushAll(getIDForGUID("unfiled"), now));
+      Logger.debug(LOG_TAG, "Done applying deletions.");
+    } catch (Exception e) {
+      Logger.error(LOG_TAG, "Unable to apply deletions.", e);
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  private void finishUp() {
+    try {
+      flushQueues();
+      Logger.debug(LOG_TAG, "Have " + parentToChildArray.size() + " folders whose children might need repositioning.");
+      for (Entry<String, JSONArray> entry : parentToChildArray.entrySet()) {
+        String guid = entry.getKey();
+        JSONArray onServer = entry.getValue();
+        try {
+          final long folderID = getIDForGUID(guid);
+          final JSONArray inDB = new JSONArray();
+          final boolean clean = getChildrenArray(folderID, false, inDB);
+          final boolean sameArrays = Utils.sameArrays(onServer, inDB);
+
+          // If the local children and the remote children are already
+          // the same, then we don't need to bump the modified time of the
+          // parent: we wouldn't upload a different record, so avoid the cycle.
+          if (!sameArrays) {
+            int added = 0;
+            for (Object o : inDB) {
+              if (!onServer.contains(o)) {
+                onServer.add(o);
+                added++;
+              }
+            }
+            Logger.debug(LOG_TAG, "Added " + added + " items locally.");
+            Logger.debug(LOG_TAG, "Untracking and bumping " + guid + "(" + folderID + ")");
+            dataAccessor.bumpModified(folderID, now());
+            untrackGUID(guid);
+          }
+
+          // If the arrays are different, or they're the same but not flushed to disk,
+          // write them out now.
+          if (!sameArrays || !clean) {
+            dataAccessor.updatePositions(new ArrayList<String>(onServer));
+          }
+        } catch (Exception e) {
+          Logger.warn(LOG_TAG, "Error repositioning children for " + guid, e);
+        }
+      }
+    } finally {
+      super.storeDone();
+    }
+  }
+
+  /**
+   * Hook into the deletion manager on wipe.
+   */
+  class BookmarkWipeRunnable extends WipeRunnable {
+    public BookmarkWipeRunnable(RepositorySessionWipeDelegate delegate) {
+      super(delegate);
+    }
+
+    @Override
+    public void run() {
+      try {
+        // Clear our queued deletions.
+        deletionManager.clear();
+        insertionManager.clear();
+        super.run();
+      } catch (Exception ex) {
+        delegate.onWipeFailed(ex);
+        return;
+      }
+    }
+  }
+
+  @Override
+  protected WipeRunnable getWipeRunnable(RepositorySessionWipeDelegate delegate) {
+    return new BookmarkWipeRunnable(delegate);
+  }
+
+  @Override
+  public void storeDone() {
+    Runnable command = new Runnable() {
+      @Override
+      public void run() {
+        finishUp();
+      }
+    };
+    storeWorkQueue.execute(command);
+  }
+
+  @Override
+  protected String buildRecordString(Record record) {
+    BookmarkRecord bmk = (BookmarkRecord) record;
+    String parent = bmk.parentName + "/";
+    if (bmk.isBookmark()) {
+      return "b" + parent + bmk.bookmarkURI + ":" + bmk.title;
+    }
+    if (bmk.isFolder()) {
+      return "f" + parent + bmk.title;
+    }
+    if (bmk.isSeparator()) {
+      return "s" + parent + bmk.androidPosition;
+    }
+    if (bmk.isQuery()) {
+      return "q" + parent + bmk.bookmarkURI;
+    }
+    return null;
+  }
+
+  public static BookmarkRecord computeParentFields(BookmarkRecord rec, String suggestedParentGUID, String suggestedParentName) {
+    final String guid = rec.guid;
+    if (guid == null) {
+      // Oh dear.
+      Logger.error(LOG_TAG, "No guid in computeParentFields!");
+      return null;
+    }
+
+    String realParent = SPECIAL_GUID_PARENTS.get(guid);
+    if (realParent == null) {
+      // No magic parent. Use whatever the caller suggests.
+      realParent = suggestedParentGUID;
+    } else {
+      Logger.debug(LOG_TAG, "Ignoring suggested parent ID " + suggestedParentGUID +
+                            " for " + guid + "; using " + realParent);
+    }
+
+    if (realParent == null) {
+      // Oh dear.
+      Logger.error(LOG_TAG, "No parent for record " + guid);
+      return null;
+    }
+
+    // Always set the parent name for special folders back to default.
+    String parentName = SPECIAL_GUIDS_MAP.get(realParent);
+    if (parentName == null) {
+      parentName = suggestedParentName;
+    }
+
+    rec.parentID = realParent;
+    rec.parentName = parentName;
+    return rec;
+  }
+
+  private static BookmarkRecord logBookmark(BookmarkRecord rec) {
+    try {
+      Logger.debug(LOG_TAG, "Returning " + (rec.deleted ? "deleted " : "") +
+                            "bookmark record " + rec.guid + " (" + rec.androidID +
+                           ", parent " + rec.parentID + ")");
+      if (!rec.deleted && Logger.LOG_PERSONAL_INFORMATION) {
+        Logger.pii(LOG_TAG, "> Parent name:      " + rec.parentName);
+        Logger.pii(LOG_TAG, "> Title:            " + rec.title);
+        Logger.pii(LOG_TAG, "> Type:             " + rec.type);
+        Logger.pii(LOG_TAG, "> URI:              " + rec.bookmarkURI);
+        Logger.pii(LOG_TAG, "> Position:         " + rec.androidPosition);
+        if (rec.isFolder()) {
+          Logger.pii(LOG_TAG, "FOLDER: Children are " +
+                             (rec.children == null ?
+                                 "null" :
+                                 rec.children.toJSONString()));
+        }
+      }
+    } catch (Exception e) {
+      Logger.debug(LOG_TAG, "Exception logging bookmark record " + rec, e);
+    }
+    return rec;
+  }
+
+  // Create a BookmarkRecord object from a cursor on a row containing a Fennec bookmark.
+  public static BookmarkRecord bookmarkFromMirrorCursor(Cursor cur, String parentGUID, String parentName, JSONArray children) {
+    final String collection = "bookmarks";
+    final String guid       = RepoUtils.getStringFromCursor(cur, BrowserContract.SyncColumns.GUID);
+    final long lastModified = RepoUtils.getLongFromCursor(cur,   BrowserContract.SyncColumns.DATE_MODIFIED);
+    final boolean deleted   = isDeleted(cur);
+    BookmarkRecord rec = new BookmarkRecord(guid, collection, lastModified, deleted);
+
+    // No point in populating it.
+    if (deleted) {
+      return logBookmark(rec);
+    }
+
+    int rowType = getTypeFromCursor(cur);
+    String typeString = BrowserContractHelpers.typeStringForCode(rowType);
+
+    if (typeString == null) {
+      Logger.warn(LOG_TAG, "Unsupported type code " + rowType);
+      return null;
+    }
+
+    Logger.trace(LOG_TAG, "Record " + guid + " has type " + typeString);
+
+    rec.type = typeString;
+    rec.title = RepoUtils.getStringFromCursor(cur, BrowserContract.Bookmarks.TITLE);
+    rec.bookmarkURI = RepoUtils.getStringFromCursor(cur, BrowserContract.Bookmarks.URL);
+    rec.description = RepoUtils.getStringFromCursor(cur, BrowserContract.Bookmarks.DESCRIPTION);
+    rec.tags = RepoUtils.getJSONArrayFromCursor(cur, BrowserContract.Bookmarks.TAGS);
+    rec.keyword = RepoUtils.getStringFromCursor(cur, BrowserContract.Bookmarks.KEYWORD);
+
+    rec.androidID = RepoUtils.getLongFromCursor(cur, BrowserContract.Bookmarks._ID);
+    rec.androidPosition = RepoUtils.getLongFromCursor(cur, BrowserContract.Bookmarks.POSITION);
+    rec.children = children;
+
+    // Need to restore the parentId since it isn't stored in content provider.
+    // We also take this opportunity to fix up parents for special folders,
+    // allowing us to map between the hierarchies used by Fennec and Places.
+    BookmarkRecord withParentFields = computeParentFields(rec, parentGUID, parentName);
+    if (withParentFields == null) {
+      // Oh dear. Something went wrong.
+      return null;
+    }
+    return logBookmark(withParentFields);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserHistoryDataAccessor.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserHistoryDataAccessor.java
new file mode 100644
index 000000000..c09d64708
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserHistoryDataAccessor.java
@@ -0,0 +1,188 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.domain.HistoryRecord;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.net.Uri;
+
+public class AndroidBrowserHistoryDataAccessor extends
+    AndroidBrowserRepositoryDataAccessor {
+
+  public AndroidBrowserHistoryDataAccessor(Context context) {
+    super(context);
+  }
+
+  @Override
+  protected Uri getUri() {
+    return BrowserContractHelpers.HISTORY_CONTENT_URI;
+  }
+
+  @Override
+  protected ContentValues getContentValues(Record record) {
+    ContentValues cv = new ContentValues();
+    HistoryRecord rec = (HistoryRecord) record;
+    cv.put(BrowserContract.History.GUID, rec.guid);
+    cv.put(BrowserContract.History.TITLE, rec.title);
+    cv.put(BrowserContract.History.URL, rec.histURI);
+    if (rec.visits != null) {
+      JSONArray visits = rec.visits;
+      long mostRecent = getLastVisited(visits);
+
+      // Fennec stores history timestamps in milliseconds, and visit timestamps in microseconds.
+      // The rest of Sync works in microseconds. This is the conversion point for records coming form Sync.
+      cv.put(BrowserContract.History.DATE_LAST_VISITED, mostRecent / 1000);
+      cv.put(BrowserContract.History.REMOTE_DATE_LAST_VISITED, mostRecent / 1000);
+      cv.put(BrowserContract.History.VISITS, Long.toString(visits.size()));
+    }
+    return cv;
+  }
+
+  @Override
+  protected String[] getAllColumns() {
+    return BrowserContractHelpers.HistoryColumns;
+  }
+
+  @Override
+  public Uri insert(Record record) {
+    HistoryRecord rec = (HistoryRecord) record;
+
+    Logger.debug(LOG_TAG, "Storing record " + record.guid);
+    Uri newRecordUri = super.insert(record);
+
+    Logger.debug(LOG_TAG, "Storing visits for " + record.guid);
+    context.getContentResolver().bulkInsert(
+            BrowserContract.Visits.CONTENT_URI,
+            VisitsHelper.getVisitsContentValues(rec.guid, rec.visits)
+    );
+
+    return newRecordUri;
+  }
+
+  /**
+   * Given oldGUID, first updates corresponding history record with new values (super operation),
+   * and then inserts visits from the new record.
+   * Existing visits from the old record are updated on database level to point to new GUID if necessary.
+   *
+   * @param oldGUID GUID of old <code>HistoryRecord</code>
+   * @param newRecord new <code>HistoryRecord</code> to replace old one with, and insert visits from
+   */
+  @Override
+  public void update(String oldGUID, Record newRecord) {
+    // First, update existing history records with new values. This might involve changing history GUID,
+    // and thanks to ON UPDATE CASCADE clause on Visits.HISTORY_GUID foreign key, visits will be "ported over"
+    // to the new GUID.
+    super.update(oldGUID, newRecord);
+
+    // Now we need to insert any visits from the new record
+    HistoryRecord rec = (HistoryRecord) newRecord;
+    String newGUID = newRecord.guid;
+    Logger.debug(LOG_TAG, "Storing visits for " + newGUID + ", replacing " + oldGUID);
+
+    context.getContentResolver().bulkInsert(
+            BrowserContract.Visits.CONTENT_URI,
+            VisitsHelper.getVisitsContentValues(newGUID, rec.visits)
+    );
+  }
+
+  /**
+   * Insert records.
+   * <p>
+   * This inserts all the records (using <code>ContentProvider.bulkInsert</code>),
+   * then inserts all the visit information (also using <code>ContentProvider.bulkInsert</code>).
+   *
+   * @param records
+   *          the records to insert.
+   * @return
+   *          the number of records actually inserted.
+   * @throws NullCursorException
+   */
+  public int bulkInsert(ArrayList<HistoryRecord> records) throws NullCursorException {
+    if (records.isEmpty()) {
+      Logger.debug(LOG_TAG, "No records to insert, returning.");
+    }
+
+    int size = records.size();
+    ContentValues[] cvs = new ContentValues[size];
+    int index = 0;
+    for (Record record : records) {
+      if (record.guid == null) {
+        throw new IllegalArgumentException("Record with null GUID passed in to bulkInsert.");
+      }
+      cvs[index] = getContentValues(record);
+      index += 1;
+    }
+
+    // First update the history records.
+    int inserted = context.getContentResolver().bulkInsert(getUri(), cvs);
+    if (inserted == size) {
+      Logger.debug(LOG_TAG, "Inserted " + inserted + " records, as expected.");
+    } else {
+      Logger.debug(LOG_TAG, "Inserted " +
+                   inserted + " records but expected " +
+                   size     + " records; continuing to update visits.");
+    }
+
+    final ContentValues remoteVisitAggregateValues = new ContentValues();
+    final Uri historyIncrementRemoteAggregateUri = getUri().buildUpon()
+            .appendQueryParameter(BrowserContract.PARAM_INCREMENT_REMOTE_AGGREGATES, "true")
+            .build();
+    for (Record record : records) {
+      HistoryRecord rec = (HistoryRecord) record;
+      if (rec.visits != null && rec.visits.size() != 0) {
+        int remoteVisitsInserted = context.getContentResolver().bulkInsert(
+                BrowserContract.Visits.CONTENT_URI,
+                VisitsHelper.getVisitsContentValues(rec.guid, rec.visits)
+        );
+
+        // If we just inserted any visits, update remote visit aggregate values.
+        // While inserting visits, we might not insert all of rec.visits - if we already have a local
+        // visit record with matching (guid,date), we will skip that visit.
+        // Remote visits aggregate value will be incremented by number of visits inserted.
+        // Note that we don't need to set REMOTE_DATE_LAST_VISITED, because it already gets set above.
+        if (remoteVisitsInserted > 0) {
+          // Note that REMOTE_VISITS must be set before calling cr.update(...) with a URI
+          // that has PARAM_INCREMENT_REMOTE_AGGREGATES=true.
+          remoteVisitAggregateValues.put(BrowserContract.History.REMOTE_VISITS, remoteVisitsInserted);
+          context.getContentResolver().update(
+                  historyIncrementRemoteAggregateUri,
+                  remoteVisitAggregateValues,
+                  BrowserContract.History.GUID + " = ?", new String[] {rec.guid}
+          );
+        }
+      }
+    }
+
+    return inserted;
+  }
+
+  /**
+   * Helper method used to find largest <code>VisitsHelper.SYNC_DATE_KEY</code> value in a provided JSONArray.
+   *
+   * @param visits Array of objects which will be searched.
+   * @return largest value of <code>VisitsHelper.SYNC_DATE_KEY</code>.
+     */
+  private long getLastVisited(JSONArray visits) {
+    long mostRecent = 0;
+    for (int i = 0; i < visits.size(); i++) {
+      final JSONObject visit = (JSONObject) visits.get(i);
+      long visitDate = (Long) visit.get(VisitsHelper.SYNC_DATE_KEY);
+      if (visitDate > mostRecent) {
+        mostRecent = visitDate;
+      }
+    }
+    return mostRecent;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserHistoryRepository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserHistoryRepository.java
new file mode 100644
index 000000000..bd2b5d31f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserHistoryRepository.java
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import org.mozilla.gecko.sync.repositories.HistoryRepository;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+
+import android.content.Context;
+
+public class AndroidBrowserHistoryRepository extends AndroidBrowserRepository implements HistoryRepository {
+
+  @Override
+  protected void sessionCreator(RepositorySessionCreationDelegate delegate, Context context) {
+    AndroidBrowserHistoryRepositorySession session = new AndroidBrowserHistoryRepositorySession(AndroidBrowserHistoryRepository.this, context);
+    delegate.onSessionCreated(session);
+  }
+
+  @Override
+  protected AndroidBrowserRepositoryDataAccessor getDataAccessor(Context context) {
+    return new AndroidBrowserHistoryDataAccessor(context);
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserHistoryRepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserHistoryRepositorySession.java
new file mode 100644
index 000000000..7c462abc3
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserHistoryRepositorySession.java
@@ -0,0 +1,208 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.repositories.InvalidSessionTransitionException;
+import org.mozilla.gecko.sync.repositories.NoGuidForIdException;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.ParentNotFoundException;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionBeginDelegate;
+import org.mozilla.gecko.sync.repositories.domain.HistoryRecord;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+import android.content.ContentProviderClient;
+import android.content.Context;
+import android.database.Cursor;
+import android.os.RemoteException;
+
+public class AndroidBrowserHistoryRepositorySession extends AndroidBrowserRepositorySession {
+  public static final String LOG_TAG = "ABHistoryRepoSess";
+
+  /**
+   * The number of records to queue for insertion before writing to databases.
+   */
+  public static final int INSERT_RECORD_THRESHOLD = 50;
+  public static final int RECENT_VISITS_LIMIT = 20;
+
+  public AndroidBrowserHistoryRepositorySession(Repository repository, Context context) {
+    super(repository);
+    dbHelper = new AndroidBrowserHistoryDataAccessor(context);
+  }
+
+  @Override
+  public void begin(RepositorySessionBeginDelegate delegate) throws InvalidSessionTransitionException {
+    // HACK: Fennec creates history records without a GUID. Mercilessly drop
+    // them on the floor. See Bug 739514.
+    try {
+      dbHelper.delete(BrowserContract.History.GUID + " IS NULL", null);
+    } catch (Exception e) {
+      // Ignore.
+    }
+    super.begin(delegate);
+  }
+
+  @Override
+  protected Record retrieveDuringStore(Cursor cur) {
+    return RepoUtils.historyFromMirrorCursor(cur);
+  }
+
+  @Override
+  protected Record retrieveDuringFetch(Cursor cur) {
+    return RepoUtils.historyFromMirrorCursor(cur);
+  }
+
+  @Override
+  protected String buildRecordString(Record record) {
+    HistoryRecord hist = (HistoryRecord) record;
+    return hist.histURI;
+  }
+
+  @Override
+  public boolean shouldIgnore(Record record) {
+    if (super.shouldIgnore(record)) {
+      return true;
+    }
+    if (!(record instanceof HistoryRecord)) {
+      return true;
+    }
+    HistoryRecord r = (HistoryRecord) record;
+    return !RepoUtils.isValidHistoryURI(r.histURI);
+  }
+
+  @Override
+  protected Record transformRecord(Record record) throws NullCursorException {
+    return addVisitsToRecord(record);
+  }
+
+  private Record addVisitsToRecord(Record record) throws NullCursorException {
+    Logger.debug(LOG_TAG, "Adding visits for GUID " + record.guid);
+
+    // Sync is an object store, so what we attach here will replace what's already present on the Sync servers.
+    // We upload just a recent subset of visits for each history record for space and bandwidth reasons.
+    // We chose 20 to be conservative.  See Bug 1164660 for details.
+    ContentProviderClient visitsClient = dbHelper.context.getContentResolver().acquireContentProviderClient(BrowserContractHelpers.VISITS_CONTENT_URI);
+    if (visitsClient == null) {
+      throw new IllegalStateException("Could not obtain a ContentProviderClient for Visits URI");
+    }
+
+    try {
+      ((HistoryRecord) record).visits = VisitsHelper.getRecentHistoryVisitsForGUID(
+              visitsClient, record.guid, RECENT_VISITS_LIMIT);
+    } catch (RemoteException e) {
+      throw new IllegalStateException("Error while obtaining visits for a record", e);
+    } finally {
+      visitsClient.release();
+    }
+
+    return record;
+  }
+
+  @Override
+  protected Record prepareRecord(Record record) {
+    return record;
+  }
+
+  protected final Object recordsBufferMonitor = new Object();
+  protected ArrayList<HistoryRecord> recordsBuffer = new ArrayList<HistoryRecord>();
+
+  /**
+   * Queue record for insertion, possibly flushing the queue.
+   * <p>
+   * Must be called on <code>storeWorkQueue</code> thread! But this is only
+   * called from <code>store</code>, which is called on the queue thread.
+   *
+   * @param record
+   *          A <code>Record</code> with a GUID that is not present locally.
+   */
+  @Override
+  protected void insert(Record record) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    enqueueNewRecord((HistoryRecord) prepareRecord(record));
+  }
+
+  /**
+   * Batch incoming records until some reasonable threshold is hit or storeDone
+   * is received.
+   * <p>
+   * Must be called on <code>storeWorkQueue</code> thread!
+   *
+   * @param record A <code>Record</code> with a GUID that is not present locally.
+   * @throws NullCursorException
+   */
+  protected void enqueueNewRecord(HistoryRecord record) throws NullCursorException {
+    synchronized (recordsBufferMonitor) {
+      if (recordsBuffer.size() >= INSERT_RECORD_THRESHOLD) {
+        flushNewRecords();
+      }
+      Logger.debug(LOG_TAG, "Enqueuing new record with GUID " + record.guid);
+      recordsBuffer.add(record);
+    }
+  }
+
+  /**
+   * Flush queue of incoming records to database.
+   * <p>
+   * Must be called on <code>storeWorkQueue</code> thread!
+   * <p>
+   * Must be locked by recordsBufferMonitor!
+   * @throws NullCursorException
+   */
+  protected void flushNewRecords() throws NullCursorException {
+    if (recordsBuffer.size() < 1) {
+      Logger.debug(LOG_TAG, "No records to flush, returning.");
+      return;
+    }
+
+    final ArrayList<HistoryRecord> outgoing = recordsBuffer;
+    recordsBuffer = new ArrayList<HistoryRecord>();
+    Logger.debug(LOG_TAG, "Flushing " + outgoing.size() + " records to database.");
+    // TODO: move bulkInsert to AndroidBrowserDataAccessor?
+    int inserted = ((AndroidBrowserHistoryDataAccessor) dbHelper).bulkInsert(outgoing);
+    if (inserted != outgoing.size()) {
+      // Something failed; most pessimistic action is to declare that all insertions failed.
+      // TODO: perform the bulkInsert in a transaction and rollback unless all insertions succeed?
+      for (HistoryRecord failed : outgoing) {
+        delegate.onRecordStoreFailed(new RuntimeException("Failed to insert history item with guid " + failed.guid + "."), failed.guid);
+      }
+      return;
+    }
+
+    // All good, everybody succeeded.
+    for (HistoryRecord succeeded : outgoing) {
+      try {
+        // Does not use androidID -- just GUID -> String map.
+        updateBookkeeping(succeeded);
+      } catch (NoGuidForIdException | ParentNotFoundException e) {
+        // Should not happen.
+        throw new NullCursorException(e);
+      } catch (NullCursorException e) {
+        throw e;
+      }
+      trackRecord(succeeded);
+      delegate.onRecordStoreSucceeded(succeeded.guid); // At this point, we are really inserted.
+    }
+  }
+
+  @Override
+  public void storeDone() {
+    storeWorkQueue.execute(new Runnable() {
+      @Override
+      public void run() {
+        synchronized (recordsBufferMonitor) {
+          try {
+            flushNewRecords();
+          } catch (Exception e) {
+            Logger.warn(LOG_TAG, "Error flushing records to database.", e);
+          }
+        }
+        storeDone(System.currentTimeMillis());
+      }
+    });
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserRepository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserRepository.java
new file mode 100644
index 000000000..6c5c661ee
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserRepository.java
@@ -0,0 +1,74 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCleanDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+
+import android.content.Context;
+
+public abstract class AndroidBrowserRepository extends Repository {
+
+  @Override
+  public void createSession(RepositorySessionCreationDelegate delegate, Context context) {
+    new CreateSessionThread(delegate, context).start();
+  }
+
+  @Override
+  public void clean(boolean success, RepositorySessionCleanDelegate delegate, Context context) {
+    // Only clean deleted records if success
+    if (success) {
+      new CleanThread(delegate, context).start();
+    }
+  }
+
+  class CleanThread extends Thread {
+    private final RepositorySessionCleanDelegate delegate;
+    private final Context context;
+
+    public CleanThread(RepositorySessionCleanDelegate delegate, Context context) {
+      if (context == null) {
+        throw new IllegalArgumentException("context is null");
+      }
+      this.delegate = delegate;
+      this.context = context;
+    }
+
+    @Override
+    public void run() {
+      try {
+        getDataAccessor(context).purgeDeleted();
+      } catch (Exception e) {
+        delegate.onCleanFailed(AndroidBrowserRepository.this, e);
+        return;
+      }
+      delegate.onCleaned(AndroidBrowserRepository.this);
+    }
+  }
+
+  protected abstract AndroidBrowserRepositoryDataAccessor getDataAccessor(Context context);
+  protected abstract void sessionCreator(RepositorySessionCreationDelegate delegate, Context context);
+
+  class CreateSessionThread extends Thread {
+    private final RepositorySessionCreationDelegate delegate;
+    private final Context context;
+
+    public CreateSessionThread(RepositorySessionCreationDelegate delegate, Context context) {
+      if (context == null) {
+        throw new IllegalArgumentException("context is null.");
+      }
+      this.delegate = delegate;
+      this.context = context;
+    }
+
+    @Override
+    public void run() {
+      sessionCreator(delegate, context);
+    }
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserRepositoryDataAccessor.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserRepositoryDataAccessor.java
new file mode 100644
index 000000000..138d63d4c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserRepositoryDataAccessor.java
@@ -0,0 +1,232 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.List;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.db.CursorDumper;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+
+public abstract class AndroidBrowserRepositoryDataAccessor {
+
+  private static final String[] GUID_COLUMNS = new String[] { BrowserContract.SyncColumns.GUID };
+  protected Context context;
+  protected static String LOG_TAG = "BrowserDataAccessor";
+  protected final RepoUtils.QueryHelper queryHelper;
+
+  public AndroidBrowserRepositoryDataAccessor(Context context) {
+    this.context = context;
+    this.queryHelper = new RepoUtils.QueryHelper(context, getUri(), LOG_TAG);
+  }
+
+  protected abstract String[] getAllColumns();
+
+  /**
+   * Produce a <code>ContentValues</code> instance that represents the provided <code>Record</code>.
+   *
+   * @param record The <code>Record</code> to be converted.
+   * @return The <code>ContentValues</code> corresponding to <code>record</code>.
+   */
+  protected abstract ContentValues getContentValues(Record record);
+
+  protected abstract Uri getUri();
+
+  /**
+   * Dump all the records in raw format.
+   */
+  public void dumpDB() {
+    Cursor cur = null;
+    try {
+      cur = queryHelper.safeQuery(".dumpDB", null, null, null, null);
+      CursorDumper.dumpCursor(cur);
+    } catch (NullCursorException e) {
+    } finally {
+      if (cur != null) {
+        cur.close();
+      }
+    }
+  }
+
+  public String dateModifiedWhere(long timestamp) {
+    return BrowserContract.SyncColumns.DATE_MODIFIED + " >= " + Long.toString(timestamp);
+  }
+
+  public void delete(String where, String[] args) {
+    Uri uri = getUri();
+    context.getContentResolver().delete(uri, where, args);
+  }
+
+  public void wipe() {
+    Logger.debug(LOG_TAG, "Wiping.");
+    delete(null, null);
+  }
+
+  public void purgeDeleted() throws NullCursorException {
+    String where = BrowserContract.SyncColumns.IS_DELETED + "= 1";
+    Uri uri = getUri();
+    Logger.info(LOG_TAG, "Purging deleted from: " + uri);
+    context.getContentResolver().delete(uri, where, null);
+  }
+
+  /**
+   * Remove matching records from the database entirely, i.e., do not set a
+   * deleted flag, delete entirely.
+   *
+   * @param guid
+   *          The GUID of the record to be deleted.
+   * @return The number of records deleted.
+   */
+  public int purgeGuid(String guid) {
+    String where  = BrowserContract.SyncColumns.GUID + " = ?";
+    String[] args = new String[] { guid };
+
+    int deleted = context.getContentResolver().delete(getUri(), where, args);
+    if (deleted != 1) {
+      Logger.warn(LOG_TAG, "Unexpectedly deleted " + deleted + " records for guid " + guid);
+    }
+    return deleted;
+  }
+
+  public void update(String guid, Record newRecord) {
+    String where  = BrowserContract.SyncColumns.GUID + " = ?";
+    String[] args = new String[] { guid };
+    ContentValues cv = getContentValues(newRecord);
+    int updated = context.getContentResolver().update(getUri(), cv, where, args);
+    if (updated != 1) {
+      Logger.warn(LOG_TAG, "Unexpectedly updated " + updated + " rows for guid " + guid);
+    }
+  }
+
+  public Uri insert(Record record) {
+    ContentValues cv = getContentValues(record);
+    return context.getContentResolver().insert(getUri(), cv);
+  }
+
+  /**
+   * Fetch all records.
+   * <p>
+   * The caller is responsible for closing the cursor.
+   *
+   * @return A cursor. You </b>must</b> close this when you're done with it.
+   * @throws NullCursorException
+   */
+  public Cursor fetchAll() throws NullCursorException {
+    return queryHelper.safeQuery(".fetchAll", getAllColumns(), null, null, null);
+  }
+
+  /**
+   * Fetch GUIDs for records modified since the provided timestamp.
+   * <p>
+   * The caller is responsible for closing the cursor.
+   *
+   * @param timestamp A timestamp in milliseconds.
+   * @return A cursor. You <b>must</b> close this when you're done with it.
+   * @throws NullCursorException
+   */
+  public Cursor getGUIDsSince(long timestamp) throws NullCursorException {
+    return queryHelper.safeQuery(".getGUIDsSince",
+                                 GUID_COLUMNS,
+                                 dateModifiedWhere(timestamp),
+                                 null, null);
+  }
+
+  /**
+   * Fetch records modified since the provided timestamp.
+   * <p>
+   * The caller is responsible for closing the cursor.
+   *
+   * @param timestamp A timestamp in milliseconds.
+   * @return A cursor. You <b>must</b> close this when you're done with it.
+   * @throws NullCursorException
+   */
+  public Cursor fetchSince(long timestamp) throws NullCursorException {
+    return queryHelper.safeQuery(".fetchSince",
+                                 getAllColumns(),
+                                 dateModifiedWhere(timestamp),
+                                 null, null);
+  }
+
+  /**
+   * Fetch records for the provided GUIDs.
+   * <p>
+   * The caller is responsible for closing the cursor.
+   *
+   * @param guids The GUIDs of the records to fetch.
+   * @return A cursor. You <b>must</b> close this when you're done with it.
+   * @throws NullCursorException
+   */
+  public Cursor fetch(String guids[]) throws NullCursorException {
+    String where = RepoUtils.computeSQLInClause(guids.length, "guid");
+    return queryHelper.safeQuery(".fetch", getAllColumns(), where, guids, null);
+  }
+
+  public void updateByGuid(String guid, ContentValues cv) {
+    String where  = BrowserContract.SyncColumns.GUID + " = ?";
+    String[] args = new String[] { guid };
+
+    int updated = context.getContentResolver().update(getUri(), cv, where, args);
+    if (updated == 1) {
+      return;
+    }
+    Logger.warn(LOG_TAG, "Unexpectedly updated " + updated + " rows for guid " + guid);
+  }
+
+  /**
+   * Insert records.
+   * <p>
+   * This inserts all the records (using <code>ContentProvider.bulkInsert</code>),
+   * but does <b>not</b> update the <code>androidID</code> of each record.
+   *
+   * @param records
+   *          the records to insert.
+   * @return
+   *          the number of records actually inserted.
+   * @throws NullCursorException
+   */
+  public int bulkInsert(List<Record> records) throws NullCursorException {
+    if (records.isEmpty()) {
+      Logger.debug(LOG_TAG, "No records to insert, returning.");
+    }
+
+    int size = records.size();
+    ContentValues[] cvs = new ContentValues[size];
+    int index = 0;
+    for (Record record : records) {
+      try {
+        cvs[index] = getContentValues(record);
+        index += 1;
+      } catch (Exception e) {
+        Logger.warn(LOG_TAG, "Got exception in getContentValues for record with guid " + record.guid, e);
+      }
+    }
+
+    if (index != size) {
+      // bulkInsert treats null ContentValues as blank rows, which we don't want
+      // to insert into the database.
+      // We expect exceptions in getContentValues to be exceedingly rare, so we
+      // re-allocate in the (rare) error case and maintain a fast path for the
+      // success case.
+      size = index;
+    }
+
+    int inserted = context.getContentResolver().bulkInsert(getUri(), cvs);
+    if (inserted == size) {
+      Logger.debug(LOG_TAG, "Inserted " + inserted + " records, as expected.");
+    } else {
+      Logger.debug(LOG_TAG, "Inserted " +
+                   inserted + " records but expected " +
+                   size     + " records.");
+    }
+    return inserted;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserRepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserRepositorySession.java
new file mode 100644
index 000000000..4f0da0bcc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/AndroidBrowserRepositorySession.java
@@ -0,0 +1,792 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.InactiveSessionException;
+import org.mozilla.gecko.sync.repositories.InvalidRequestException;
+import org.mozilla.gecko.sync.repositories.InvalidSessionTransitionException;
+import org.mozilla.gecko.sync.repositories.MultipleRecordsForGuidException;
+import org.mozilla.gecko.sync.repositories.NoGuidForIdException;
+import org.mozilla.gecko.sync.repositories.NoStoreDelegateException;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.ParentNotFoundException;
+import org.mozilla.gecko.sync.repositories.ProfileDatabaseException;
+import org.mozilla.gecko.sync.repositories.RecordFilter;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.StoreTrackingRepositorySession;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionBeginDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionGuidsSinceDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionWipeDelegate;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+import android.content.ContentUris;
+import android.database.Cursor;
+import android.net.Uri;
+import android.util.SparseArray;
+
+/**
+ * You'll notice that all delegate calls *either*:
+ *
+ * - request a deferred delegate with the appropriate work queue, then
+ *   make the appropriate call, or
+ * - create a Runnable which makes the appropriate call, and pushes it
+ *   directly into the appropriate work queue.
+ *
+ * This is to ensure that all delegate callbacks happen off the current
+ * thread. This provides lock safety (we don't enter another method that
+ * might try to take a lock already taken in our caller), and ensures
+ * that operations take place off the main thread.
+ *
+ * Don't do both -- the two approaches are equivalent -- and certainly
+ * don't do neither unless you know what you're doing!
+ *
+ * Similarly, all store calls go through the appropriate store queue. This
+ * ensures that store() and storeDone() consequences occur before-after.
+ *
+ * @author rnewman
+ *
+ */
+public abstract class AndroidBrowserRepositorySession extends StoreTrackingRepositorySession {
+  public static final String LOG_TAG = "BrowserRepoSession";
+
+  protected AndroidBrowserRepositoryDataAccessor dbHelper;
+
+  /**
+   * In order to reconcile the "same record" with two *different* GUIDs (for
+   * example, the same bookmark created by two different clients), we maintain a
+   * mapping for each local record from a "record string" to
+   * "local record GUID".
+   * <p>
+   * The "record string" above is a "record identifying unique key" produced by
+   * <code>buildRecordString</code>.
+   * <p>
+   * Since we hash each "record string", this map may produce a false positive.
+   * In this case, we search the database for a matching record explicitly using
+   * <code>findByRecordString</code>.
+   */
+  protected SparseArray<String> recordToGuid;
+
+  public AndroidBrowserRepositorySession(Repository repository) {
+    super(repository);
+  }
+
+  /**
+   * Retrieve a record from a cursor. Act as if we don't know the final contents of
+   * the record: for example, a folder's child array might change.
+   *
+   * Return null if this record should not be processed.
+   *
+   * @throws NoGuidForIdException
+   * @throws NullCursorException
+   * @throws ParentNotFoundException
+   */
+  protected abstract Record retrieveDuringStore(Cursor cur) throws NoGuidForIdException, NullCursorException, ParentNotFoundException;
+
+  /**
+   * Retrieve a record from a cursor. Ensure that the contents of the database are
+   * updated to match the record that we're constructing: for example, the children
+   * of a folder might be repositioned as we generate the folder's record.
+   *
+   * @throws NoGuidForIdException
+   * @throws NullCursorException
+   * @throws ParentNotFoundException
+   */
+  protected abstract Record retrieveDuringFetch(Cursor cur) throws NoGuidForIdException, NullCursorException, ParentNotFoundException;
+
+  /**
+   * Override this to allow records to be skipped during insertion.
+   *
+   * For example, a session subclass might skip records of an unsupported type.
+   */
+  @SuppressWarnings("static-method")
+  public boolean shouldIgnore(Record record) {
+    return false;
+  }
+
+  /**
+   * Perform any necessary transformation of a record prior to searching by
+   * any field other than GUID.
+   *
+   * Example: translating remote folder names into local names.
+   */
+  @SuppressWarnings("static-method")
+  protected void fixupRecord(Record record) {
+    return;
+  }
+
+  /**
+   * Override in subclass to implement record extension.
+   *
+   * Populate any fields of the record that are expensive to calculate,
+   * prior to reconciling.
+   *
+   * Example: computing children arrays.
+   *
+   * Return null if this record should not be processed.
+   *
+   * @param record
+   *        The record to transform. Can be null.
+   * @return The transformed record. Can be null.
+   * @throws NullCursorException
+   */
+  @SuppressWarnings("static-method")
+  protected Record transformRecord(Record record) throws NullCursorException {
+    return record;
+  }
+
+  @Override
+  public void begin(RepositorySessionBeginDelegate delegate) throws InvalidSessionTransitionException {
+    RepositorySessionBeginDelegate deferredDelegate = delegate.deferredBeginDelegate(delegateQueue);
+    super.sharedBegin();
+
+    try {
+      // We do this check here even though it results in one extra call to the DB
+      // because if we didn't, we have to do a check on every other call since there
+      // is no way of knowing which call would be hit first.
+      checkDatabase();
+    } catch (ProfileDatabaseException e) {
+      Logger.error(LOG_TAG, "ProfileDatabaseException from begin. Fennec must be launched once until this error is fixed");
+      deferredDelegate.onBeginFailed(e);
+      return;
+    } catch (Exception e) {
+      deferredDelegate.onBeginFailed(e);
+      return;
+    }
+    storeTracker = createStoreTracker();
+    deferredDelegate.onBeginSucceeded(this);
+  }
+
+  @Override
+  public void finish(RepositorySessionFinishDelegate delegate) throws InactiveSessionException {
+    dbHelper = null;
+    recordToGuid = null;
+    super.finish(delegate);
+  }
+
+  /**
+   * Produce a "record string" (record identifying unique key).
+   *
+   * @param record
+   *          the <code>Record</code> to identify.
+   * @return a <code>String</code> instance.
+   */
+  protected abstract String buildRecordString(Record record);
+
+  protected void checkDatabase() throws ProfileDatabaseException, NullCursorException {
+    Logger.debug(LOG_TAG, "BEGIN: checking database.");
+    try {
+      dbHelper.fetch(new String[] { "none" }).close();
+      Logger.debug(LOG_TAG, "END: checking database.");
+    } catch (NullPointerException e) {
+      throw new ProfileDatabaseException(e);
+    }
+  }
+
+  @Override
+  public void guidsSince(long timestamp, RepositorySessionGuidsSinceDelegate delegate) {
+    GuidsSinceRunnable command = new GuidsSinceRunnable(timestamp, delegate);
+    delegateQueue.execute(command);
+  }
+
+  class GuidsSinceRunnable implements Runnable {
+
+    private final RepositorySessionGuidsSinceDelegate delegate;
+    private final long                                timestamp;
+
+    public GuidsSinceRunnable(long timestamp,
+                              RepositorySessionGuidsSinceDelegate delegate) {
+      this.timestamp = timestamp;
+      this.delegate = delegate;
+    }
+
+    @Override
+    public void run() {
+      if (!isActive()) {
+        delegate.onGuidsSinceFailed(new InactiveSessionException(null));
+        return;
+      }
+
+      Cursor cur;
+      try {
+        cur = dbHelper.getGUIDsSince(timestamp);
+      } catch (Exception e) {
+        delegate.onGuidsSinceFailed(e);
+        return;
+      }
+
+      ArrayList<String> guids;
+      try {
+        if (!cur.moveToFirst()) {
+          delegate.onGuidsSinceSucceeded(new String[] {});
+          return;
+        }
+        guids = new ArrayList<String>();
+        while (!cur.isAfterLast()) {
+          guids.add(RepoUtils.getStringFromCursor(cur, "guid"));
+          cur.moveToNext();
+        }
+      } finally {
+        Logger.debug(LOG_TAG, "Closing cursor after guidsSince.");
+        cur.close();
+      }
+
+      String guidsArray[] = new String[guids.size()];
+      guids.toArray(guidsArray);
+      delegate.onGuidsSinceSucceeded(guidsArray);
+    }
+  }
+
+  @Override
+  public void fetch(String[] guids,
+                    RepositorySessionFetchRecordsDelegate delegate) throws InactiveSessionException {
+    FetchRunnable command = new FetchRunnable(guids, now(), null, delegate);
+    executeDelegateCommand(command);
+  }
+
+  abstract class FetchingRunnable implements Runnable {
+    protected final RepositorySessionFetchRecordsDelegate delegate;
+
+    public FetchingRunnable(RepositorySessionFetchRecordsDelegate delegate) {
+      this.delegate = delegate;
+    }
+
+    protected void fetchFromCursor(Cursor cursor, RecordFilter filter, long end) {
+      Logger.debug(LOG_TAG, "Fetch from cursor:");
+      try {
+        try {
+          if (!cursor.moveToFirst()) {
+            delegate.onFetchCompleted(end);
+            return;
+          }
+          while (!cursor.isAfterLast()) {
+            Record r = retrieveDuringFetch(cursor);
+            if (r != null) {
+              if (filter == null || !filter.excludeRecord(r)) {
+                Logger.trace(LOG_TAG, "Processing record " + r.guid);
+                delegate.onFetchedRecord(transformRecord(r));
+              } else {
+                Logger.debug(LOG_TAG, "Skipping filtered record " + r.guid);
+              }
+            }
+            cursor.moveToNext();
+          }
+          delegate.onFetchCompleted(end);
+        } catch (NoGuidForIdException e) {
+          Logger.warn(LOG_TAG, "No GUID for ID.", e);
+          delegate.onFetchFailed(e, null);
+        } catch (Exception e) {
+          Logger.warn(LOG_TAG, "Exception in fetchFromCursor.", e);
+          delegate.onFetchFailed(e, null);
+          return;
+        }
+      } finally {
+        Logger.trace(LOG_TAG, "Closing cursor after fetch.");
+        cursor.close();
+      }
+    }
+  }
+
+  public class FetchRunnable extends FetchingRunnable {
+    private final String[] guids;
+    private final long     end;
+    private final RecordFilter filter;
+
+    public FetchRunnable(String[] guids,
+                         long end,
+                         RecordFilter filter,
+                         RepositorySessionFetchRecordsDelegate delegate) {
+      super(delegate);
+      this.guids  = guids;
+      this.end    = end;
+      this.filter = filter;
+    }
+
+    @Override
+    public void run() {
+      if (!isActive()) {
+        delegate.onFetchFailed(new InactiveSessionException(null), null);
+        return;
+      }
+
+      if (guids == null || guids.length < 1) {
+        Logger.error(LOG_TAG, "No guids sent to fetch");
+        delegate.onFetchFailed(new InvalidRequestException(null), null);
+        return;
+      }
+
+      try {
+        Cursor cursor = dbHelper.fetch(guids);
+        this.fetchFromCursor(cursor, filter, end);
+      } catch (NullCursorException e) {
+        delegate.onFetchFailed(e, null);
+      }
+    }
+  }
+
+  @Override
+  public void fetchSince(long timestamp,
+                         RepositorySessionFetchRecordsDelegate delegate) {
+    if (this.storeTracker == null) {
+      throw new IllegalStateException("Store tracker not yet initialized!");
+    }
+
+    Logger.debug(LOG_TAG, "Running fetchSince(" + timestamp + ").");
+    FetchSinceRunnable command = new FetchSinceRunnable(timestamp, now(), this.storeTracker.getFilter(), delegate);
+    delegateQueue.execute(command);
+  }
+
+  class FetchSinceRunnable extends FetchingRunnable {
+    private final long since;
+    private final long end;
+    private final RecordFilter filter;
+
+    public FetchSinceRunnable(long since,
+                              long end,
+                              RecordFilter filter,
+                              RepositorySessionFetchRecordsDelegate delegate) {
+      super(delegate);
+      this.since  = since;
+      this.end    = end;
+      this.filter = filter;
+    }
+
+    @Override
+    public void run() {
+      if (!isActive()) {
+        delegate.onFetchFailed(new InactiveSessionException(null), null);
+        return;
+      }
+
+      try {
+        Cursor cursor = dbHelper.fetchSince(since);
+        this.fetchFromCursor(cursor, filter, end);
+      } catch (NullCursorException e) {
+        delegate.onFetchFailed(e, null);
+        return;
+      }
+    }
+  }
+
+  @Override
+  public void fetchAll(RepositorySessionFetchRecordsDelegate delegate) {
+    this.fetchSince(0, delegate);
+  }
+
+  protected int storeCount = 0;
+
+  @Override
+  public void store(final Record record) throws NoStoreDelegateException {
+    if (delegate == null) {
+      throw new NoStoreDelegateException();
+    }
+    if (record == null) {
+      Logger.error(LOG_TAG, "Record sent to store was null");
+      throw new IllegalArgumentException("Null record passed to AndroidBrowserRepositorySession.store().");
+    }
+
+    storeCount += 1;
+    Logger.debug(LOG_TAG, "Storing record with GUID " + record.guid + " (stored " + storeCount + " records this session).");
+
+    // Store Runnables *must* complete synchronously. It's OK, they
+    // run on a background thread.
+    Runnable command = new Runnable() {
+
+      @Override
+      public void run() {
+        if (!isActive()) {
+          Logger.warn(LOG_TAG, "AndroidBrowserRepositorySession is inactive. Store failing.");
+          delegate.onRecordStoreFailed(new InactiveSessionException(null), record.guid);
+          return;
+        }
+
+        // Check that the record is a valid type.
+        // Fennec only supports bookmarks and folders. All other types of records,
+        // including livemarks and queries, are simply ignored.
+        // See Bug 708149. This might be resolved by Fennec changing its database
+        // schema, or by Sync storing non-applied records in its own private database.
+        if (shouldIgnore(record)) {
+          Logger.debug(LOG_TAG, "Ignoring record " + record.guid);
+
+          // Don't throw: we don't want to abort the entire sync when we get a livemark!
+          // delegate.onRecordStoreFailed(new InvalidBookmarkTypeException(null));
+          return;
+        }
+
+
+        // TODO: lift these into the session.
+        // Temporary: this matches prior syncing semantics, in which only
+        // the relationship between the local and remote record is considered.
+        // In the future we'll track these two timestamps and use them to
+        // determine which records have changed, and thus process incoming
+        // records more efficiently.
+        long lastLocalRetrieval  = 0;      // lastSyncTimestamp?
+        long lastRemoteRetrieval = 0;      // TODO: adjust for clock skew.
+        boolean remotelyModified = record.lastModified > lastRemoteRetrieval;
+
+        Record existingRecord;
+        try {
+          // GUID matching only: deleted records don't have a payload with which to search.
+          existingRecord = retrieveByGUIDDuringStore(record.guid);
+          if (record.deleted) {
+            if (existingRecord == null) {
+              // We're done. Don't bother with a callback. That can change later
+              // if we want it to.
+              trace("Incoming record " + record.guid + " is deleted, and no local version. Bye!");
+              return;
+            }
+
+            if (existingRecord.deleted) {
+              trace("Local record already deleted. Bye!");
+              return;
+            }
+
+            // Which one wins?
+            if (!remotelyModified) {
+              trace("Ignoring deleted record from the past.");
+              return;
+            }
+
+            boolean locallyModified = existingRecord.lastModified > lastLocalRetrieval;
+            if (!locallyModified) {
+              trace("Remote modified, local not. Deleting.");
+              storeRecordDeletion(record, existingRecord);
+              return;
+            }
+
+            trace("Both local and remote records have been modified.");
+            if (record.lastModified > existingRecord.lastModified) {
+              trace("Remote is newer, and deleted. Deleting local.");
+              storeRecordDeletion(record, existingRecord);
+              return;
+            }
+
+            trace("Remote is older, local is not deleted. Ignoring.");
+            return;
+          }
+          // End deletion logic.
+
+          // Now we're processing a non-deleted incoming record.
+          // Apply any changes we need in order to correctly find existing records.
+          fixupRecord(record);
+
+          if (existingRecord == null) {
+            trace("Looking up match for record " + record.guid);
+            existingRecord = findExistingRecord(record);
+          }
+
+          if (existingRecord == null) {
+            // The record is new.
+            trace("No match. Inserting.");
+            insert(record);
+            return;
+          }
+
+          // We found a local dupe.
+          trace("Incoming record " + record.guid + " dupes to local record " + existingRecord.guid);
+
+          // Populate more expensive fields prior to reconciling.
+          existingRecord = transformRecord(existingRecord);
+          Record toStore = reconcileRecords(record, existingRecord, lastRemoteRetrieval, lastLocalRetrieval);
+
+          if (toStore == null) {
+            Logger.debug(LOG_TAG, "Reconciling returned null. Not inserting a record.");
+            return;
+          }
+
+          // TODO: pass in timestamps?
+
+          // This section of code will only run if the incoming record is not
+          // marked as deleted, so we never want to just drop ours from the database:
+          // we need to upload it later.
+          // Allowing deleted items to propagate through `replace` allows normal
+          // logging and side-effects to occur, and is no more expensive than simply
+          // bumping the modified time.
+          Logger.debug(LOG_TAG, "Replacing existing " + existingRecord.guid +
+                       (toStore.deleted ? " with deleted record " : " with record ") +
+                       toStore.guid);
+          Record replaced = replace(toStore, existingRecord);
+
+          // Note that we don't track records here; deciding that is the job
+          // of reconcileRecords.
+          Logger.debug(LOG_TAG, "Calling delegate callback with guid " + replaced.guid +
+                                "(" + replaced.androidID + ")");
+          delegate.onRecordStoreSucceeded(replaced.guid);
+          return;
+
+        } catch (MultipleRecordsForGuidException e) {
+          Logger.error(LOG_TAG, "Multiple records returned for given guid: " + record.guid);
+          delegate.onRecordStoreFailed(e, record.guid);
+          return;
+        } catch (NoGuidForIdException e) {
+          Logger.error(LOG_TAG, "Store failed for " + record.guid, e);
+          delegate.onRecordStoreFailed(e, record.guid);
+          return;
+        } catch (Exception e) {
+          Logger.error(LOG_TAG, "Store failed for " + record.guid, e);
+          delegate.onRecordStoreFailed(e, record.guid);
+          return;
+        }
+      }
+    };
+    storeWorkQueue.execute(command);
+  }
+
+  /**
+   * Process a request for deletion of a record.
+   * Neither argument will ever be null.
+   *
+   * @param record the incoming record. This will be mostly blank, given that it's a deletion.
+   * @param existingRecord the existing record. Use this to decide how to process the deletion.
+   */
+  protected void storeRecordDeletion(final Record record, final Record existingRecord) {
+    // TODO: we ought to mark the record as deleted rather than purging it,
+    // in order to support syncing to multiple destinations. Bug 722607.
+    dbHelper.purgeGuid(record.guid);
+    delegate.onRecordStoreSucceeded(record.guid);
+  }
+
+  protected void insert(Record record) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    Record toStore = prepareRecord(record);
+    Uri recordURI = dbHelper.insert(toStore);
+    if (recordURI == null) {
+      throw new NullCursorException(new RuntimeException("Got null URI inserting record with guid " + record.guid));
+    }
+    toStore.androidID = ContentUris.parseId(recordURI);
+
+    updateBookkeeping(toStore);
+    trackRecord(toStore);
+    delegate.onRecordStoreSucceeded(toStore.guid);
+
+    Logger.debug(LOG_TAG, "Inserted record with guid " + toStore.guid + " as androidID " + toStore.androidID);
+  }
+
+  protected Record replace(Record newRecord, Record existingRecord) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    Record toStore = prepareRecord(newRecord);
+
+    // newRecord should already have suitable androidID and guid.
+    dbHelper.update(existingRecord.guid, toStore);
+    updateBookkeeping(toStore);
+    Logger.debug(LOG_TAG, "replace() returning record " + toStore.guid);
+    return toStore;
+  }
+
+  /**
+   * Retrieve a record from the store by GUID, without writing unnecessarily to the
+   * database.
+   *
+   * @throws NoGuidForIdException
+   * @throws NullCursorException
+   * @throws ParentNotFoundException
+   * @throws MultipleRecordsForGuidException
+   */
+  protected Record retrieveByGUIDDuringStore(String guid) throws
+                                             NoGuidForIdException,
+                                             NullCursorException,
+                                             ParentNotFoundException,
+                                             MultipleRecordsForGuidException {
+    Cursor cursor = dbHelper.fetch(new String[] { guid });
+    try {
+      if (!cursor.moveToFirst()) {
+        return null;
+      }
+
+      Record r = retrieveDuringStore(cursor);
+
+      cursor.moveToNext();
+      if (cursor.isAfterLast()) {
+        // Got one record!
+        return r; // Not transformed.
+      }
+
+      // More than one. Oh dear.
+      throw (new MultipleRecordsForGuidException(null));
+    } finally {
+      cursor.close();
+    }
+  }
+
+  /**
+   * Attempt to find an equivalent record through some means other than GUID.
+   *
+   * @param record
+   *        The record for which to search.
+   * @return
+   *        An equivalent Record object, or null if none is found.
+   *
+   * @throws MultipleRecordsForGuidException
+   * @throws NoGuidForIdException
+   * @throws NullCursorException
+   * @throws ParentNotFoundException
+   */
+  protected Record findExistingRecord(Record record) throws MultipleRecordsForGuidException,
+    NoGuidForIdException, NullCursorException, ParentNotFoundException {
+
+    Logger.debug(LOG_TAG, "Finding existing record for incoming record with GUID " + record.guid);
+    String recordString = buildRecordString(record);
+    if (recordString == null) {
+      Logger.debug(LOG_TAG, "No record string for incoming record " + record.guid);
+      return null;
+    }
+
+    if (Logger.LOG_PERSONAL_INFORMATION) {
+      Logger.pii(LOG_TAG, "Searching with record string " + recordString);
+    } else {
+      Logger.debug(LOG_TAG, "Searching with record string.");
+    }
+    String guid = getGuidForString(recordString);
+    if (guid == null) {
+      Logger.debug(LOG_TAG, "Failed to find existing record for " + record.guid);
+      return null;
+    }
+
+    // Our map contained a match, but it could be a false positive. Since
+    // computed record string is supposed to be a unique key, we can easily
+    // verify our positive.
+    Logger.debug(LOG_TAG, "Found one. Checking stored record.");
+    Record stored = retrieveByGUIDDuringStore(guid);
+    String storedRecordString = buildRecordString(record);
+    if (recordString.equals(storedRecordString)) {
+      Logger.debug(LOG_TAG, "Existing record matches incoming record.  Returning existing record.");
+      return stored;
+    }
+
+    // Oh no, we got a false positive! (This should be *very* rare --
+    // essentially, we got a hash collision.) Search the DB for this record
+    // explicitly by hand.
+    Logger.debug(LOG_TAG, "Existing record does not match incoming record.  Trying to find record by record string.");
+    return findByRecordString(recordString);
+  }
+
+  protected String getGuidForString(String recordString) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    if (recordToGuid == null) {
+      createRecordToGuidMap();
+    }
+    return recordToGuid.get(recordString.hashCode());
+  }
+
+  protected void createRecordToGuidMap() throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    Logger.info(LOG_TAG, "BEGIN: creating record -> GUID map.");
+    recordToGuid = new SparseArray<String>();
+
+    // TODO: we should be able to do this entire thing with string concatenations within SQL.
+    // Also consider whether it's better to fetch and process every record in the DB into
+    // memory, or run a query per record to do the same thing.
+    Cursor cur = dbHelper.fetchAll();
+    try {
+      if (!cur.moveToFirst()) {
+        return;
+      }
+      while (!cur.isAfterLast()) {
+        Record record = retrieveDuringStore(cur);
+        if (record != null) {
+          final String recordString = buildRecordString(record);
+          if (recordString != null) {
+            recordToGuid.put(recordString.hashCode(), record.guid);
+          }
+        }
+        cur.moveToNext();
+      }
+    } finally {
+      cur.close();
+    }
+    Logger.info(LOG_TAG, "END: creating record -> GUID map.");
+  }
+
+  /**
+   * Search the local database for a record with the same "record string".
+   * <p>
+   * We expect to do this only in the unlikely event of a hash
+   * collision, so we iterate the database completely.  Since we want
+   * to include information about the parents of bookmarks, it is
+   * difficult to do better purely using the
+   * <code>ContentProvider</code> interface.
+   *
+   * @param recordString
+   *          the "record string" to search for; must be n
+   * @return a <code>Record</code> with the same "record string", or
+   *         <code>null</code> if none is present.
+   * @throws ParentNotFoundException
+   * @throws NullCursorException
+   * @throws NoGuidForIdException
+   */
+  protected Record findByRecordString(String recordString) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    Cursor cur = dbHelper.fetchAll();
+    try {
+      if (!cur.moveToFirst()) {
+        return null;
+      }
+      while (!cur.isAfterLast()) {
+        Record record = retrieveDuringStore(cur);
+        if (record != null) {
+          final String storedRecordString = buildRecordString(record);
+          if (recordString.equals(storedRecordString)) {
+            return record;
+          }
+        }
+        cur.moveToNext();
+      }
+      return null;
+    } finally {
+      cur.close();
+    }
+  }
+
+  public void putRecordToGuidMap(String recordString, String guid) throws NoGuidForIdException, NullCursorException, ParentNotFoundException {
+    if (recordString == null) {
+      return;
+    }
+
+    if (recordToGuid == null) {
+      createRecordToGuidMap();
+    }
+    recordToGuid.put(recordString.hashCode(), guid);
+  }
+
+  protected abstract Record prepareRecord(Record record);
+
+  protected void updateBookkeeping(Record record) throws NoGuidForIdException,
+                                                 NullCursorException,
+                                                 ParentNotFoundException {
+    putRecordToGuidMap(buildRecordString(record), record.guid);
+  }
+
+  protected WipeRunnable getWipeRunnable(RepositorySessionWipeDelegate delegate) {
+    return new WipeRunnable(delegate);
+  }
+
+  @Override
+  public void wipe(RepositorySessionWipeDelegate delegate) {
+    Runnable command = getWipeRunnable(delegate);
+    storeWorkQueue.execute(command);
+  }
+
+  class WipeRunnable implements Runnable {
+    protected RepositorySessionWipeDelegate delegate;
+
+    public WipeRunnable(RepositorySessionWipeDelegate delegate) {
+      this.delegate = delegate;
+    }
+
+    @Override
+    public void run() {
+      if (!isActive()) {
+        delegate.onWipeFailed(new InactiveSessionException(null));
+        return;
+      }
+      dbHelper.wipe();
+      delegate.onWipeSucceeded();
+    }
+  }
+
+  // For testing purposes.
+  public AndroidBrowserRepositoryDataAccessor getDBHelper() {
+    return dbHelper;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/BookmarksDeletionManager.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/BookmarksDeletionManager.java
new file mode 100644
index 000000000..d8d8756f7
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/BookmarksDeletionManager.java
@@ -0,0 +1,239 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionStoreDelegate;
+
+/**
+ * Queue up deletions. Process them at the end.
+ *
+ * Algorithm:
+ *
+ * * Collect GUIDs as we go. For convenience we partition these into
+ *   folders and non-folders.
+ *
+ * * Non-folders can be deleted in batches as we go.
+ *
+ * * At the end of the sync:
+ *   * Delete all that aren't folders.
+ *   * Move the remaining children of any that are folders to an "Orphans" folder.
+ *     - We do this even for children that are _marked_ as deleted -- we still want
+ *       to upload them, and their parent is irrelevant.
+ *   * Delete all the folders.
+ *
+ * * Any outstanding records -- the ones we moved to "Orphans" -- are true orphans.
+ *   These should be reuploaded (because their parent has changed), as should their
+ *   new parent (because its children array has changed).
+ *   We achieve the former by moving them without tracking (but we don't make any
+ *   special effort here -- warning! Lurking bug!).
+ *   We achieve the latter by bumping its mtime. The caller should take care of untracking it.
+ *
+ * Note that we make no particular effort to handle repositioning or reparenting:
+ * batching deletes at the end should be handled seamlessly by existing code,
+ * because the deleted records could have arrived in a batch at the end regardless.
+ *
+ * Note that this class is not thread safe. This should be fine: call it only
+ * from within a store runnable.
+ *
+ */
+public class BookmarksDeletionManager {
+  private static final String LOG_TAG = "BookmarkDelete";
+
+  private final AndroidBrowserBookmarksDataAccessor dataAccessor;
+  private RepositorySessionStoreDelegate delegate;
+
+  private final int flushThreshold;
+
+  private final HashSet<String> folders    = new HashSet<String>();
+  private final HashSet<String> nonFolders = new HashSet<String>();
+  private int nonFolderCount = 0;
+
+  // Records that we need to touch once we've deleted the non-folders.
+  private HashSet<String> nonFolderParents = new HashSet<String>();
+  private HashSet<String> folderParents    = new HashSet<String>();
+
+  /**
+   * Create an instance to be used for tracking deletions in a bookmarks
+   * repository session.
+   *
+   * @param dataAccessor
+   *        Used to effect database changes.
+   *
+   * @param flushThreshold
+   *        When this many non-folder records have been stored for deletion,
+   *        an incremental flush occurs.
+   */
+  public BookmarksDeletionManager(AndroidBrowserBookmarksDataAccessor dataAccessor, int flushThreshold) {
+    this.dataAccessor = dataAccessor;
+    this.flushThreshold = flushThreshold;
+  }
+
+  /**
+   * Set the delegate to use for callbacks.
+   * If not invoked, no callbacks will be submitted.
+   *
+   * @param delegate a delegate, which should already be a delayed delegate.
+   */
+  public void setDelegate(RepositorySessionStoreDelegate delegate) {
+    this.delegate = delegate;
+  }
+
+  public void deleteRecord(String guid, boolean isFolder, String parentGUID) {
+    if (guid == null) {
+      Logger.warn(LOG_TAG, "Cannot queue deletion of record with no GUID.");
+      return;
+    }
+    Logger.debug(LOG_TAG, "Queuing deletion of " + guid);
+
+    if (isFolder) {
+      folders.add(guid);
+      if (!folders.contains(parentGUID)) {
+        // We're not going to delete its parent; will need to bump it.
+        folderParents.add(parentGUID);
+      }
+
+      nonFolderParents.remove(guid);
+      folderParents.remove(guid);
+      return;
+    }
+
+    if (!folders.contains(parentGUID)) {
+      // We're not going to delete its parent; will need to bump it.
+      nonFolderParents.add(parentGUID);
+    }
+
+    if (nonFolders.add(guid)) {
+      if (++nonFolderCount >= flushThreshold) {
+        deleteNonFolders();
+      }
+    }
+  }
+
+  /**
+   * Flush deletions that can be easily taken care of right now.
+   */
+  public void incrementalFlush() {
+    // Yes, this means we only bump when we finish, not during an incremental flush.
+    deleteNonFolders();
+  }
+
+  /**
+   * Apply all pending deletions and reset state for the next batch of stores.
+   *
+   * @param orphanDestination the ID of the folder to which orphaned children
+   *                          should be moved.
+   *
+   * @throws NullCursorException
+   * @return a set of IDs to untrack. Will not be null.
+   */
+  public Set<String> flushAll(long orphanDestination, long now) throws NullCursorException {
+    Logger.debug(LOG_TAG, "Doing complete flush of deleted items. Moving orphans to " + orphanDestination);
+    deleteNonFolders();
+
+    // Find out which parents *won't* be deleted, and thus need to have their
+    // modified times bumped.
+    nonFolderParents.removeAll(folders);
+
+    Logger.debug(LOG_TAG, "Bumping modified times for " + nonFolderParents.size() +
+                          " parents of deleted non-folders.");
+    dataAccessor.bumpModifiedByGUID(nonFolderParents, now);
+
+    if (folders.size() > 0) {
+      final String[] folderGUIDs = folders.toArray(new String[folders.size()]);
+      final String[] folderIDs = getIDs(folderGUIDs);   // Throws if any don't exist.
+      int moved = dataAccessor.moveChildren(folderIDs, orphanDestination);
+      if (moved > 0) {
+        dataAccessor.bumpModified(orphanDestination, now);
+      }
+
+      // We've deleted or moved anything that might be under these folders.
+      // Just delete them.
+      final String folderWhere = RepoUtils.computeSQLInClause(folders.size(), BrowserContract.Bookmarks.GUID);
+      dataAccessor.delete(folderWhere, folderGUIDs);
+      invokeCallbacks(delegate, folderGUIDs);
+
+      folderParents.removeAll(folders);
+      Logger.debug(LOG_TAG, "Bumping modified times for " + folderParents.size() +
+                            " parents of deleted folders.");
+      dataAccessor.bumpModifiedByGUID(folderParents, now);
+
+      // Clean up.
+      folders.clear();
+    }
+
+    HashSet<String> ret = nonFolderParents;
+    ret.addAll(folderParents);
+
+    nonFolderParents = new HashSet<String>();
+    folderParents    = new HashSet<String>();
+    return ret;
+  }
+
+  private String[] getIDs(String[] guids) throws NullCursorException {
+    // Convert GUIDs to numeric IDs.
+    String[] ids = new String[guids.length];
+    Map<String, Long> guidsToIDs = dataAccessor.idsForGUIDs(guids);
+    for (int i = 0; i < guids.length; ++i) {
+      String guid = guids[i];
+      Long id =  guidsToIDs.get(guid);
+      if (id == null) {
+        throw new IllegalArgumentException("Can't get ID for unknown record " + guid);
+      }
+      ids[i] = id.toString();
+    }
+    return ids;
+  }
+
+  /**
+   * Flush non-folder deletions. This can be called at any time.
+   */
+  private void deleteNonFolders() {
+    if (nonFolderCount == 0) {
+      Logger.debug(LOG_TAG, "No non-folders to delete.");
+      return;
+    }
+
+    Logger.debug(LOG_TAG, "Applying deletion of " + nonFolderCount + " non-folders.");
+    final String[] nonFolderGUIDs = nonFolders.toArray(new String[nonFolderCount]);
+    final String nonFolderWhere = RepoUtils.computeSQLInClause(nonFolderCount, BrowserContract.Bookmarks.GUID);
+    dataAccessor.delete(nonFolderWhere, nonFolderGUIDs);
+
+    invokeCallbacks(delegate, nonFolderGUIDs);
+
+    // Discard these.
+    // Note that we maintain folderParents and nonFolderParents; we need them later.
+    nonFolders.clear();
+    nonFolderCount = 0;
+  }
+
+  private void invokeCallbacks(RepositorySessionStoreDelegate delegate,
+                               String[] nonFolderGUIDs) {
+    if (delegate == null) {
+      return;
+    }
+    Logger.trace(LOG_TAG, "Invoking store callback for " + nonFolderGUIDs.length + " GUIDs.");
+    for (String guid : nonFolderGUIDs) {
+      delegate.onRecordStoreSucceeded(guid);
+    }
+  }
+
+  /**
+   * Clear state in case of redundancy (e.g., wipe).
+   */
+  public void clear() {
+    nonFolders.clear();
+    nonFolderCount = 0;
+    folders.clear();
+    nonFolderParents.clear();
+    folderParents.clear();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/BookmarksInsertionManager.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/BookmarksInsertionManager.java
new file mode 100644
index 000000000..98670d39b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/BookmarksInsertionManager.java
@@ -0,0 +1,298 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.repositories.domain.BookmarkRecord;
+
+/**
+ * Queue up insertions:
+ * <ul>
+ * <li>Folder inserts where the parent is known. Do these immediately, because
+ * they allow other records to be inserted. Requires bookkeeping updates. On
+ * insert, flush the next set.</li>
+ * <li>Regular inserts where the parent is known. These can happen whenever.
+ * Batch for speed.</li>
+ * <li>Records where the parent is not known. These can be flushed out when the
+ * parent is known, or entered as orphans. This can be a queue earlier in the
+ * process, so they don't get assigned to Unsorted. Feed into the main batch
+ * when the parent arrives.</li>
+ * </ul>
+ * <p>
+ * Deletions are always done at the end so that orphaning is minimized, and
+ * that's why we are batching folders and non-folders separately.
+ * <p>
+ * Updates are always applied as they arrive.
+ * <p>
+ * Note that this class is not thread safe. This should be fine: call it only
+ * from within a store runnable.
+ */
+public class BookmarksInsertionManager {
+  public static final String LOG_TAG = "BookmarkInsert";
+  public static boolean DEBUG = false;
+
+  protected final int flushThreshold;
+  protected final BookmarkInserter inserter;
+
+  /**
+   * Folders that have been successfully inserted.
+   */
+  private final Set<String> insertedFolders = new HashSet<String>();
+
+  /**
+   * Non-folders waiting for bulk insertion.
+   * <p>
+   * We write in insertion order to keep things easy to debug.
+   */
+  private final Set<BookmarkRecord> nonFoldersToWrite = new LinkedHashSet<BookmarkRecord>();
+
+  /**
+   * Map from parent folder GUID to child records (folders and non-folders)
+   * waiting to be enqueued after parent folder is inserted.
+   */
+  private final Map<String, Set<BookmarkRecord>> recordsWaitingForParent = new HashMap<String, Set<BookmarkRecord>>();
+
+  /**
+   * Create an instance to be used for tracking insertions in a bookmarks
+   * repository session.
+   *
+   * @param flushThreshold
+   *        When this many non-folder records have been stored for insertion,
+   *        an incremental flush occurs.
+   * @param insertedFolders
+   *        The GUIDs of all the folders already inserted into the database.
+   * @param inserter
+   *        The <code>BookmarkInsert</code> to use.
+   */
+  public BookmarksInsertionManager(int flushThreshold, Collection<String> insertedFolders, BookmarkInserter inserter) {
+    this.flushThreshold = flushThreshold;
+    this.insertedFolders.addAll(insertedFolders);
+    this.inserter = inserter;
+  }
+
+  protected void addRecordWithUnwrittenParent(BookmarkRecord record) {
+    Set<BookmarkRecord> destination = recordsWaitingForParent.get(record.parentID);
+    if (destination == null) {
+      destination = new LinkedHashSet<BookmarkRecord>();
+      recordsWaitingForParent.put(record.parentID, destination);
+    }
+    destination.add(record);
+  }
+
+  /**
+   * If <code>record</code> is a folder, insert it immediately; if it is a
+   * non-folder, enqueue it. Then do the same for any records waiting for this record.
+   *
+   * @param record
+   *          the <code>BookmarkRecord</code> to enqueue.
+   */
+  protected void recursivelyEnqueueRecordAndChildren(BookmarkRecord record) {
+    if (record.isFolder()) {
+      if (!inserter.insertFolder(record)) {
+        Logger.warn(LOG_TAG, "Folder with known parent with guid " + record.parentID + " failed to insert!");
+        return;
+      }
+      Logger.debug(LOG_TAG, "Folder with known parent with guid " + record.parentID + " inserted; adding to inserted folders.");
+      insertedFolders.add(record.guid);
+    } else {
+      Logger.debug(LOG_TAG, "Non-folder has known parent with guid " + record.parentID + "; adding to insertion queue.");
+      nonFoldersToWrite.add(record);
+    }
+
+    // Now process record's children.
+    Set<BookmarkRecord> waiting = recordsWaitingForParent.remove(record.guid);
+    if (waiting == null) {
+      return;
+    }
+    for (BookmarkRecord waiter : waiting) {
+      recursivelyEnqueueRecordAndChildren(waiter);
+    }
+  }
+
+  /**
+   * Enqueue a folder.
+   *
+   * @param record
+   *          the folder to enqueue.
+   */
+  protected void enqueueFolder(BookmarkRecord record) {
+    Logger.debug(LOG_TAG, "Inserting folder with guid " + record.guid);
+
+    if (!insertedFolders.contains(record.parentID)) {
+      Logger.debug(LOG_TAG, "Folder has unknown parent with guid " + record.parentID + "; keeping until we see the parent.");
+      addRecordWithUnwrittenParent(record);
+      return;
+    }
+
+    // Parent is known; add as much of the tree as this roots.
+    recursivelyEnqueueRecordAndChildren(record);
+    flushNonFoldersIfNecessary();
+  }
+
+  /**
+   * Enqueue a non-folder.
+   *
+   * @param record
+   *          the non-folder to enqueue.
+   */
+  protected void enqueueNonFolder(BookmarkRecord record) {
+    Logger.debug(LOG_TAG, "Inserting non-folder with guid " + record.guid);
+
+    if (!insertedFolders.contains(record.parentID)) {
+      Logger.debug(LOG_TAG, "Non-folder has unknown parent with guid " + record.parentID + "; keeping until we see the parent.");
+      addRecordWithUnwrittenParent(record);
+      return;
+    }
+
+    // Parent is known; add to insertion queue and maybe write.
+    Logger.debug(LOG_TAG, "Non-folder has known parent with guid " + record.parentID + "; adding to insertion queue.");
+    nonFoldersToWrite.add(record);
+    flushNonFoldersIfNecessary();
+  }
+
+  /**
+   * Enqueue a bookmark record for eventual insertion.
+   *
+   * @param record
+   *          the <code>BookmarkRecord</code> to enqueue.
+   */
+  public void enqueueRecord(BookmarkRecord record) {
+    if (record.isFolder()) {
+      enqueueFolder(record);
+    } else {
+      enqueueNonFolder(record);
+    }
+    if (DEBUG) {
+      dumpState();
+    }
+  }
+
+  /**
+   * Flush non-folders; empties the insertion queue entirely.
+   */
+  protected void flushNonFolders() {
+    inserter.bulkInsertNonFolders(nonFoldersToWrite); // All errors are handled in bulkInsertNonFolders.
+    nonFoldersToWrite.clear();
+  }
+
+  /**
+   * Flush non-folder insertions if there are many of them; empties the
+   * insertion queue entirely.
+   */
+  protected void flushNonFoldersIfNecessary() {
+    int num = nonFoldersToWrite.size();
+    if (num < flushThreshold) {
+      Logger.debug(LOG_TAG, "Incremental flush called with " + num + " < " + flushThreshold + " non-folders; not flushing.");
+      return;
+    }
+    Logger.debug(LOG_TAG, "Incremental flush called with " + num + " non-folders; flushing.");
+    flushNonFolders();
+  }
+
+  /**
+   * Insert all remaining folders followed by all remaining non-folders,
+   * regardless of whether parent records have been successfully inserted.
+   */
+  public void finishUp() {
+    // Iterate through all waiting records, writing the folders and collecting
+    // the non-folders for bulk insertion.
+    int numFolders = 0;
+    int numNonFolders = 0;
+    for (Set<BookmarkRecord> records : recordsWaitingForParent.values()) {
+      for (BookmarkRecord record : records) {
+        if (!record.isFolder()) {
+          numNonFolders += 1;
+          nonFoldersToWrite.add(record);
+          continue;
+        }
+
+        numFolders += 1;
+        if (!inserter.insertFolder(record)) {
+          Logger.warn(LOG_TAG, "Folder with known parent with guid " + record.parentID + " failed to insert!");
+          continue;
+        }
+
+        Logger.debug(LOG_TAG, "Folder with known parent with guid " + record.parentID + " inserted; adding to inserted folders.");
+        insertedFolders.add(record.guid);
+      }
+    }
+    recordsWaitingForParent.clear();
+    flushNonFolders();
+
+    Logger.debug(LOG_TAG, "finishUp inserted " +
+        numFolders + " folders without known parents and " +
+        numNonFolders + " non-folders without known parents.");
+    if (DEBUG) {
+      dumpState();
+    }
+  }
+
+  public void clear() {
+    this.insertedFolders.clear();
+    this.nonFoldersToWrite.clear();
+    this.recordsWaitingForParent.clear();
+  }
+
+  // For debugging.
+  public boolean isClear() {
+    return nonFoldersToWrite.isEmpty() && recordsWaitingForParent.isEmpty();
+  }
+
+  // For debugging.
+  public void dumpState() {
+    ArrayList<String> readies = new ArrayList<String>();
+    for (BookmarkRecord record : nonFoldersToWrite) {
+      readies.add(record.guid);
+    }
+    String ready = Utils.toCommaSeparatedString(new ArrayList<String>(readies));
+
+    ArrayList<String> waits = new ArrayList<String>();
+    for (Set<BookmarkRecord> recs : recordsWaitingForParent.values()) {
+      for (BookmarkRecord rec : recs) {
+        waits.add(rec.guid);
+      }
+    }
+    String waiting = Utils.toCommaSeparatedString(waits);
+    String known = Utils.toCommaSeparatedString(insertedFolders);
+
+    Logger.debug(LOG_TAG, "Q=(" + ready + "), W = (" + waiting + "), P=(" + known + ")");
+  }
+
+  public interface BookmarkInserter {
+    /**
+     * Insert a single folder.
+     * <p>
+     * All exceptions should be caught and all delegate callbacks invoked here.
+     *
+     * @param record
+     *          the record to insert.
+     * @return
+     *          <code>true</code> if the folder was inserted; <code>false</code> otherwise.
+     */
+    public boolean insertFolder(BookmarkRecord record);
+
+    /**
+     * Insert many non-folders. Each non-folder's parent was already present in
+     * the database before this <code>BookmarkInsertionsManager</code> was
+     * created, or had <code>insertFolder</code> called with it as argument (and
+     * possibly was not inserted).
+     * <p>
+     * All exceptions should be caught and all delegate callbacks invoked here.
+     *
+     * @param records
+     *          the records to insert.
+     */
+    public void bulkInsertNonFolders(Collection<BookmarkRecord> records);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/BrowserContractHelpers.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/BrowserContractHelpers.java
new file mode 100644
index 000000000..e83aea087
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/BrowserContractHelpers.java
@@ -0,0 +1,154 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.setup.Constants;
+
+import android.net.Uri;
+
+public class BrowserContractHelpers extends BrowserContract {
+
+  protected static Uri withSyncAndDeletedAndProfile(Uri u) {
+    return u.buildUpon()
+            .appendQueryParameter(PARAM_PROFILE, Constants.DEFAULT_PROFILE)
+            .appendQueryParameter(PARAM_IS_SYNC, "true")
+            .appendQueryParameter(PARAM_SHOW_DELETED, "true")
+            .build();
+  }
+  protected static Uri withSyncAndProfile(Uri u) {
+    return u.buildUpon()
+        .appendQueryParameter(PARAM_PROFILE, Constants.DEFAULT_PROFILE)
+        .appendQueryParameter(PARAM_IS_SYNC, "true")
+        .build();
+  }
+
+  public static final Uri BOOKMARKS_CONTENT_URI            = withSyncAndDeletedAndProfile(Bookmarks.CONTENT_URI);
+  public static final Uri BOOKMARKS_PARENTS_CONTENT_URI    = withSyncAndDeletedAndProfile(Bookmarks.PARENTS_CONTENT_URI);
+  public static final Uri BOOKMARKS_POSITIONS_CONTENT_URI  = withSyncAndDeletedAndProfile(Bookmarks.POSITIONS_CONTENT_URI);
+  public static final Uri HISTORY_CONTENT_URI              = withSyncAndDeletedAndProfile(History.CONTENT_URI);
+  public static final Uri VISITS_CONTENT_URI               = withSyncAndDeletedAndProfile(Visits.CONTENT_URI);
+  public static final Uri SCHEMA_CONTENT_URI               = withSyncAndDeletedAndProfile(Schema.CONTENT_URI);
+  public static final Uri PASSWORDS_CONTENT_URI            = withSyncAndDeletedAndProfile(Passwords.CONTENT_URI);
+  public static final Uri DELETED_PASSWORDS_CONTENT_URI    = withSyncAndDeletedAndProfile(DeletedPasswords.CONTENT_URI);
+  public static final Uri FORM_HISTORY_CONTENT_URI         = withSyncAndProfile(FormHistory.CONTENT_URI);
+  public static final Uri DELETED_FORM_HISTORY_CONTENT_URI = withSyncAndProfile(DeletedFormHistory.CONTENT_URI);
+  public static final Uri TABS_CONTENT_URI                 = withSyncAndProfile(Tabs.CONTENT_URI);
+  public static final Uri CLIENTS_CONTENT_URI              = withSyncAndProfile(Clients.CONTENT_URI);
+  public static final Uri LOGINS_CONTENT_URI               = withSyncAndProfile(Logins.CONTENT_URI);
+
+  public static final String[] PasswordColumns = new String[] {
+    Passwords.ID,
+    Passwords.HOSTNAME,
+    Passwords.HTTP_REALM,
+    Passwords.FORM_SUBMIT_URL,
+    Passwords.USERNAME_FIELD,
+    Passwords.PASSWORD_FIELD,
+    Passwords.ENCRYPTED_USERNAME,
+    Passwords.ENCRYPTED_PASSWORD,
+    Passwords.ENC_TYPE,
+    Passwords.TIME_CREATED,
+    Passwords.TIME_LAST_USED,
+    Passwords.TIME_PASSWORD_CHANGED,
+    Passwords.TIMES_USED,
+    Passwords.GUID
+  };
+
+  public static final String[] HistoryColumns = new String[] {
+    CommonColumns._ID,
+    SyncColumns.GUID,
+    SyncColumns.DATE_CREATED,
+    SyncColumns.DATE_MODIFIED,
+    SyncColumns.IS_DELETED,
+    History.TITLE,
+    History.URL,
+    History.DATE_LAST_VISITED,
+    History.VISITS
+  };
+
+  public static final String[] BookmarkColumns = new String[] {
+    CommonColumns._ID,
+    SyncColumns.GUID,
+    SyncColumns.DATE_CREATED,
+    SyncColumns.DATE_MODIFIED,
+    SyncColumns.IS_DELETED,
+    Bookmarks.TITLE,
+    Bookmarks.URL,
+    Bookmarks.TYPE,
+    Bookmarks.PARENT,
+    Bookmarks.POSITION,
+    Bookmarks.TAGS,
+    Bookmarks.DESCRIPTION,
+    Bookmarks.KEYWORD
+  };
+
+  public static final String[] FormHistoryColumns = new String[] {
+    FormHistory.ID,
+    FormHistory.GUID,
+    FormHistory.FIELD_NAME,
+    FormHistory.VALUE,
+    FormHistory.TIMES_USED,
+    FormHistory.FIRST_USED,
+    FormHistory.LAST_USED
+  };
+
+  public static final String[] DeletedColumns = new String[] {
+    BrowserContract.DeletedColumns.ID,
+    BrowserContract.DeletedColumns.GUID,
+    BrowserContract.DeletedColumns.TIME_DELETED
+  };
+
+  // Mapping from Sync types to Fennec types.
+  public static final String[] BOOKMARK_TYPE_CODE_TO_STRING = {
+    // Observe omissions: "microsummary", "item".
+    "folder", "bookmark", "separator", "livemark", "query"
+  };
+  private static final int MAX_BOOKMARK_TYPE_CODE = BOOKMARK_TYPE_CODE_TO_STRING.length - 1;
+  public static final Map<String, Integer> BOOKMARK_TYPE_STRING_TO_CODE;
+  static {
+    HashMap<String, Integer> t = new HashMap<String, Integer>();
+    t.put("folder",    Bookmarks.TYPE_FOLDER);
+    t.put("bookmark",  Bookmarks.TYPE_BOOKMARK);
+    t.put("separator", Bookmarks.TYPE_SEPARATOR);
+    t.put("livemark",  Bookmarks.TYPE_LIVEMARK);
+    t.put("query",     Bookmarks.TYPE_QUERY);
+    BOOKMARK_TYPE_STRING_TO_CODE = Collections.unmodifiableMap(t);
+  }
+
+  /**
+   * Convert a database bookmark type code into the Sync string equivalent.
+   *
+   * @param code one of the <code>Bookmarks.TYPE_*</code> enumerations.
+   * @return the string equivalent, or null if not found.
+   */
+  public static String typeStringForCode(int code) {
+    if (0 <= code && code <= MAX_BOOKMARK_TYPE_CODE) {
+      return BOOKMARK_TYPE_CODE_TO_STRING[code];
+    }
+    return null;
+  }
+
+  /**
+   * Convert a Sync type string into a Fennec type code.
+   *
+   * @param type a type string, such as "livemark".
+   * @return the type code, or -1 if not found.
+   */
+  public static int typeCodeForString(String type) {
+    Integer found = BOOKMARK_TYPE_STRING_TO_CODE.get(type);
+    if (found == null) {
+      return -1;
+    }
+    return found;
+  }
+
+  public static boolean isSupportedType(String type) {
+    return BOOKMARK_TYPE_STRING_TO_CODE.containsKey(type);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/CachedSQLiteOpenHelper.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/CachedSQLiteOpenHelper.java
new file mode 100644
index 000000000..5c17f9b85
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/CachedSQLiteOpenHelper.java
@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import android.content.Context;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteDatabase.CursorFactory;
+import android.database.sqlite.SQLiteOpenHelper;
+
+public abstract class CachedSQLiteOpenHelper extends SQLiteOpenHelper {
+
+  public CachedSQLiteOpenHelper(Context context, String name, CursorFactory factory,
+      int version) {
+    super(context, name, factory, version);
+  }
+
+  // Cache these so we don't have to track them across cursors. Call `close`
+  // when you're done.
+  private SQLiteDatabase readableDatabase;
+  private SQLiteDatabase writableDatabase;
+
+  synchronized protected SQLiteDatabase getCachedReadableDatabase() {
+    if (readableDatabase == null) {
+      if (writableDatabase == null) {
+        readableDatabase = this.getReadableDatabase();
+        return readableDatabase;
+      } else {
+        return writableDatabase;
+      }
+    } else {
+      return readableDatabase;
+    }
+  }
+
+  synchronized protected SQLiteDatabase getCachedWritableDatabase() {
+    if (writableDatabase == null) {
+      writableDatabase = this.getWritableDatabase();
+    }
+    return writableDatabase;
+  }
+
+  @Override
+  synchronized public void close() {
+    if (readableDatabase != null) {
+      readableDatabase.close();
+      readableDatabase = null;
+    }
+    if (writableDatabase != null) {
+      writableDatabase.close();
+      writableDatabase = null;
+    }
+    super.close();
+  }
+
+  // Used for testing.
+  public boolean isClosed() {
+    return readableDatabase == null &&
+           writableDatabase == null;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/ClientsDatabase.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/ClientsDatabase.java
new file mode 100644
index 000000000..4962a20c6
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/ClientsDatabase.java
@@ -0,0 +1,252 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.domain.ClientRecord;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+
+public class ClientsDatabase extends CachedSQLiteOpenHelper {
+
+  public static final String LOG_TAG = "ClientsDatabase";
+
+  // Database Specifications.
+  protected static final String DB_NAME = "clients_database";
+  protected static final int SCHEMA_VERSION = 3;
+
+  // Clients Table.
+  public static final String TBL_CLIENTS      = "clients";
+  public static final String COL_ACCOUNT_GUID = "guid";
+  public static final String COL_PROFILE      = "profile";
+  public static final String COL_NAME         = "name";
+  public static final String COL_TYPE         = "device_type";
+
+  // Optional fields.
+  public static final String COL_FORMFACTOR = "formfactor";
+  public static final String COL_OS = "os";
+  public static final String COL_APPLICATION = "application";
+  public static final String COL_APP_PACKAGE = "appPackage";
+  public static final String COL_DEVICE = "device";
+
+  public static final String[] TBL_CLIENTS_COLUMNS = new String[] { COL_ACCOUNT_GUID, COL_PROFILE, COL_NAME, COL_TYPE,
+                                                                    COL_FORMFACTOR, COL_OS, COL_APPLICATION, COL_APP_PACKAGE, COL_DEVICE };
+  public static final String TBL_CLIENTS_KEY = COL_ACCOUNT_GUID + " = ? AND " +
+                                               COL_PROFILE + " = ?";
+
+  // Commands Table.
+  public static final String TBL_COMMANDS = "commands";
+  public static final String COL_COMMAND  = "command";
+  public static final String COL_ARGS     = "args";
+
+  public static final String[] TBL_COMMANDS_COLUMNS    = new String[] { COL_ACCOUNT_GUID, COL_COMMAND, COL_ARGS };
+  public static final String   TBL_COMMANDS_KEY        = COL_ACCOUNT_GUID + " = ? AND " +
+                                                         COL_COMMAND + " = ? AND " +
+                                                         COL_ARGS + " = ?";
+  public static final String   TBL_COMMANDS_GUID_QUERY = COL_ACCOUNT_GUID + " = ? ";
+
+  private final RepoUtils.QueryHelper queryHelper;
+
+  public ClientsDatabase(Context context) {
+    super(context, DB_NAME, null, SCHEMA_VERSION);
+    this.queryHelper = new RepoUtils.QueryHelper(context, null, LOG_TAG);
+    Logger.debug(LOG_TAG, "ClientsDatabase instantiated.");
+  }
+
+  @Override
+  public void onCreate(SQLiteDatabase db) {
+    Logger.debug(LOG_TAG, "ClientsDatabase.onCreate().");
+    createClientsTable(db);
+    createCommandsTable(db);
+  }
+
+  public static void createClientsTable(SQLiteDatabase db) {
+    Logger.debug(LOG_TAG, "ClientsDatabase.createClientsTable().");
+    String createClientsTableSql = "CREATE TABLE " + TBL_CLIENTS + " ("
+        + COL_ACCOUNT_GUID + " TEXT, "
+        + COL_PROFILE + " TEXT, "
+        + COL_NAME + " TEXT, "
+        + COL_TYPE + " TEXT, "
+        + COL_FORMFACTOR + " TEXT, "
+        + COL_OS + " TEXT, "
+        + COL_APPLICATION + " TEXT, "
+        + COL_APP_PACKAGE + " TEXT, "
+        + COL_DEVICE + " TEXT, "
+        + "PRIMARY KEY (" + COL_ACCOUNT_GUID + ", " + COL_PROFILE + "))";
+    db.execSQL(createClientsTableSql);
+  }
+
+  public static void createCommandsTable(SQLiteDatabase db) {
+    Logger.debug(LOG_TAG, "ClientsDatabase.createCommandsTable().");
+    String createCommandsTableSql = "CREATE TABLE " + TBL_COMMANDS + " ("
+        + COL_ACCOUNT_GUID + " TEXT, "
+        + COL_COMMAND + " TEXT, "
+        + COL_ARGS + " TEXT, "
+        + "PRIMARY KEY (" + COL_ACCOUNT_GUID + ", " + COL_COMMAND + ", " + COL_ARGS + "), "
+        + "FOREIGN KEY (" + COL_ACCOUNT_GUID + ") REFERENCES " + TBL_CLIENTS + " (" + COL_ACCOUNT_GUID + "))";
+    db.execSQL(createCommandsTableSql);
+  }
+
+  @Override
+  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+    Logger.debug(LOG_TAG, "ClientsDatabase.onUpgrade(" + oldVersion + ", " + newVersion + ").");
+    if (oldVersion < 2) {
+      // For now we'll just drop and recreate the tables.
+      db.execSQL("DROP TABLE IF EXISTS " + TBL_CLIENTS);
+      db.execSQL("DROP TABLE IF EXISTS " + TBL_COMMANDS);
+      onCreate(db);
+      return;
+    }
+
+    if (newVersion >= 3) {
+      // Add the optional columns to clients.
+      db.execSQL("ALTER TABLE " + TBL_CLIENTS + " ADD COLUMN " + COL_FORMFACTOR + " TEXT");
+      db.execSQL("ALTER TABLE " + TBL_CLIENTS + " ADD COLUMN " + COL_OS + " TEXT");
+      db.execSQL("ALTER TABLE " + TBL_CLIENTS + " ADD COLUMN " + COL_APPLICATION + " TEXT");
+      db.execSQL("ALTER TABLE " + TBL_CLIENTS + " ADD COLUMN " + COL_APP_PACKAGE + " TEXT");
+      db.execSQL("ALTER TABLE " + TBL_CLIENTS + " ADD COLUMN " + COL_DEVICE + " TEXT");
+    }
+  }
+
+  public void wipeDB() {
+    SQLiteDatabase db = this.getCachedWritableDatabase();
+    onUpgrade(db, 0, SCHEMA_VERSION);
+  }
+
+  public void wipeClientsTable() {
+    SQLiteDatabase db = this.getCachedWritableDatabase();
+    db.execSQL("DELETE FROM " + TBL_CLIENTS);
+  }
+
+  public void wipeCommandsTable() {
+    SQLiteDatabase db = this.getCachedWritableDatabase();
+    db.execSQL("DELETE FROM " + TBL_COMMANDS);
+  }
+
+  // If a record with given GUID exists, we'll update it,
+  // otherwise we'll insert it.
+  public void store(String profileId, ClientRecord record) {
+    SQLiteDatabase db = this.getCachedWritableDatabase();
+
+    ContentValues cv = new ContentValues();
+    cv.put(COL_ACCOUNT_GUID, record.guid);
+    cv.put(COL_PROFILE, profileId);
+    cv.put(COL_NAME, record.name);
+    cv.put(COL_TYPE, record.type);
+
+    if (record.formfactor != null) {
+      cv.put(COL_FORMFACTOR, record.formfactor);
+    }
+
+    if (record.os != null) {
+      cv.put(COL_OS, record.os);
+    }
+
+    if (record.application != null) {
+      cv.put(COL_APPLICATION, record.application);
+    }
+
+    if (record.appPackage != null) {
+      cv.put(COL_APP_PACKAGE, record.appPackage);
+    }
+
+    if (record.device != null) {
+      cv.put(COL_DEVICE, record.device);
+    }
+
+    String[] args = new String[] { record.guid, profileId };
+    int rowsUpdated = db.update(TBL_CLIENTS, cv, TBL_CLIENTS_KEY, args);
+
+    if (rowsUpdated >= 1) {
+      Logger.debug(LOG_TAG, "Replaced client record for row with accountGUID " + record.guid);
+    } else {
+      long rowId = db.insert(TBL_CLIENTS, null, cv);
+      Logger.debug(LOG_TAG, "Inserted client record into row: " + rowId);
+    }
+  }
+
+  /**
+   * Store a command in the commands database if it doesn't already exist.
+   *
+   * @param accountGUID
+   * @param command - The command type
+   * @param args - A JSON string of args
+   * @throws NullCursorException
+   */
+  public void store(String accountGUID, String command, String args) throws NullCursorException {
+    if (Logger.LOG_PERSONAL_INFORMATION) {
+      Logger.pii(LOG_TAG, "Storing command " + command + " with args " + args);
+    } else {
+      Logger.trace(LOG_TAG, "Storing command " + command + ".");
+    }
+    SQLiteDatabase db = this.getCachedWritableDatabase();
+
+    ContentValues cv = new ContentValues();
+    cv.put(COL_ACCOUNT_GUID, accountGUID);
+    cv.put(COL_COMMAND, command);
+    if (args == null) {
+      cv.put(COL_ARGS, "[]");
+    } else {
+      cv.put(COL_ARGS, args);
+    }
+
+    Cursor cur = this.fetchSpecificCommand(accountGUID, command, args);
+    try {
+      if (cur.moveToFirst()) {
+        Logger.debug(LOG_TAG, "Command already exists in database.");
+        return;
+      }
+    } finally {
+      cur.close();
+    }
+
+    long rowId = db.insert(TBL_COMMANDS, null, cv);
+    Logger.debug(LOG_TAG, "Inserted command into row: " + rowId);
+  }
+
+  public Cursor fetchClientsCursor(String accountGUID, String profileId) throws NullCursorException {
+    String[] args = new String[] { accountGUID, profileId };
+    SQLiteDatabase db = this.getCachedReadableDatabase();
+
+    return queryHelper.safeQuery(db, ".fetchClientsCursor", TBL_CLIENTS, TBL_CLIENTS_COLUMNS, TBL_CLIENTS_KEY, args);
+  }
+
+  public Cursor fetchSpecificCommand(String accountGUID, String command, String commandArgs) throws NullCursorException {
+    String[] args = new String[] { accountGUID, command, commandArgs };
+    SQLiteDatabase db = this.getCachedReadableDatabase();
+
+    return queryHelper.safeQuery(db, ".fetchSpecificCommand", TBL_COMMANDS, TBL_COMMANDS_COLUMNS, TBL_COMMANDS_KEY, args);
+  }
+
+  public Cursor fetchCommandsForClient(String accountGUID) throws NullCursorException {
+    String[] args = new String[] { accountGUID };
+    SQLiteDatabase db = this.getCachedReadableDatabase();
+
+    return queryHelper.safeQuery(db, ".fetchCommandsForClient", TBL_COMMANDS, TBL_COMMANDS_COLUMNS, TBL_COMMANDS_GUID_QUERY, args);
+  }
+
+  public Cursor fetchAllClients() throws NullCursorException {
+    SQLiteDatabase db = this.getCachedReadableDatabase();
+
+    return queryHelper.safeQuery(db, ".fetchAllClients", TBL_CLIENTS, TBL_CLIENTS_COLUMNS, null, null);
+  }
+
+  public Cursor fetchAllCommands() throws NullCursorException {
+    SQLiteDatabase db = this.getCachedReadableDatabase();
+
+    return queryHelper.safeQuery(db, ".fetchAllCommands", TBL_COMMANDS, TBL_COMMANDS_COLUMNS, null, null);
+  }
+
+  public void deleteClient(String accountGUID, String profileId) {
+    String[] args = new String[] { accountGUID, profileId };
+
+    SQLiteDatabase db = this.getCachedWritableDatabase();
+    db.delete(TBL_CLIENTS, TBL_CLIENTS_KEY, args);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/ClientsDatabaseAccessor.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/ClientsDatabaseAccessor.java
new file mode 100644
index 000000000..4af84ceaf
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/ClientsDatabaseAccessor.java
@@ -0,0 +1,178 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.json.simple.JSONArray;
+
+import org.mozilla.gecko.sync.CommandProcessor.Command;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.domain.ClientRecord;
+import org.mozilla.gecko.sync.setup.Constants;
+
+import android.content.Context;
+import android.database.Cursor;
+
+public class ClientsDatabaseAccessor {
+
+  public static final String LOG_TAG = "ClientsDatabaseAccessor";
+
+  private ClientsDatabase db;
+
+  // Need this so we can properly stub out the class for testing.
+  public ClientsDatabaseAccessor() {}
+
+  public ClientsDatabaseAccessor(Context context) {
+    db = new ClientsDatabase(context);
+  }
+
+  public void store(ClientRecord record) {
+    db.store(getProfileId(), record);
+  }
+
+  public void store(Collection<ClientRecord> records) {
+    for (ClientRecord record : records) {
+      this.store(record);
+    }
+  }
+
+  public void store(String accountGUID, Command command) throws NullCursorException {
+    db.store(accountGUID, command.commandType, command.args.toJSONString());
+  }
+
+  public ClientRecord fetchClient(String accountGUID) throws NullCursorException {
+    final Cursor cur = db.fetchClientsCursor(accountGUID, getProfileId());
+    try {
+      if (!cur.moveToFirst()) {
+        return null;
+      }
+      return recordFromCursor(cur);
+    } finally {
+      cur.close();
+    }
+  }
+
+  public Map<String, ClientRecord> fetchAllClients() throws NullCursorException {
+    final HashMap<String, ClientRecord> map = new HashMap<String, ClientRecord>();
+    final Cursor cur = db.fetchAllClients();
+    try {
+      if (!cur.moveToFirst()) {
+        return Collections.unmodifiableMap(map);
+      }
+
+      while (!cur.isAfterLast()) {
+        ClientRecord clientRecord = recordFromCursor(cur);
+        map.put(clientRecord.guid, clientRecord);
+        cur.moveToNext();
+      }
+      return Collections.unmodifiableMap(map);
+    } finally {
+      cur.close();
+    }
+  }
+
+  public List<Command> fetchAllCommands() throws NullCursorException {
+    final List<Command> commands = new ArrayList<Command>();
+    final Cursor cur = db.fetchAllCommands();
+    try {
+      if (!cur.moveToFirst()) {
+        return Collections.unmodifiableList(commands);
+      }
+
+      while (!cur.isAfterLast()) {
+        Command command = commandFromCursor(cur);
+        commands.add(command);
+        cur.moveToNext();
+      }
+      return Collections.unmodifiableList(commands);
+    } finally {
+      cur.close();
+    }
+  }
+
+  public List<Command> fetchCommandsForClient(String accountGUID) throws NullCursorException {
+    final List<Command> commands = new ArrayList<Command>();
+    final Cursor cur = db.fetchCommandsForClient(accountGUID);
+    try {
+      if (!cur.moveToFirst()) {
+        return Collections.unmodifiableList(commands);
+      }
+
+      while(!cur.isAfterLast()) {
+        Command command = commandFromCursor(cur);
+        commands.add(command);
+        cur.moveToNext();
+      }
+      return Collections.unmodifiableList(commands);
+    } finally {
+      cur.close();
+    }
+  }
+
+  protected static ClientRecord recordFromCursor(Cursor cur) {
+    final String accountGUID = RepoUtils.getStringFromCursor(cur, ClientsDatabase.COL_ACCOUNT_GUID);
+    final String clientName = RepoUtils.getStringFromCursor(cur, ClientsDatabase.COL_NAME);
+    final String clientType = RepoUtils.getStringFromCursor(cur, ClientsDatabase.COL_TYPE);
+
+    final ClientRecord record = new ClientRecord(accountGUID);
+    record.name = clientName;
+    record.type = clientType;
+
+    // Optional fields. These will either be null or strings.
+    record.formfactor = RepoUtils.optStringFromCursor(cur, ClientsDatabase.COL_FORMFACTOR);
+    record.os = RepoUtils.optStringFromCursor(cur, ClientsDatabase.COL_OS);
+    record.device = RepoUtils.optStringFromCursor(cur, ClientsDatabase.COL_DEVICE);
+    record.appPackage = RepoUtils.optStringFromCursor(cur, ClientsDatabase.COL_APP_PACKAGE);
+    record.application = RepoUtils.optStringFromCursor(cur, ClientsDatabase.COL_APPLICATION);
+
+    return record;
+  }
+
+  protected static Command commandFromCursor(Cursor cur) {
+    String commandType = RepoUtils.getStringFromCursor(cur, ClientsDatabase.COL_COMMAND);
+    JSONArray commandArgs = RepoUtils.getJSONArrayFromCursor(cur, ClientsDatabase.COL_ARGS);
+    return new Command(commandType, commandArgs);
+  }
+
+  public int clientsCount() {
+    try {
+      final Cursor cur = db.fetchAllClients();
+      try {
+        return cur.getCount();
+      } finally {
+        cur.close();
+      }
+    } catch (NullCursorException e) {
+      return 0;
+    }
+
+  }
+
+  private String getProfileId() {
+    return Constants.DEFAULT_PROFILE;
+  }
+
+  public void wipeDB() {
+    db.wipeDB();
+  }
+
+  public void wipeClientsTable() {
+    db.wipeClientsTable();
+  }
+
+  public void wipeCommandsTable() {
+    db.wipeCommandsTable();
+  }
+
+  public void close() {
+    db.close();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/FennecTabsRepository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/FennecTabsRepository.java
new file mode 100644
index 000000000..720d856eb
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/FennecTabsRepository.java
@@ -0,0 +1,383 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.db.Tab;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.db.BrowserContract.Clients;
+import org.mozilla.gecko.sync.delegates.ClientsDataDelegate;
+import org.mozilla.gecko.sync.repositories.InactiveSessionException;
+import org.mozilla.gecko.sync.repositories.NoContentProviderException;
+import org.mozilla.gecko.sync.repositories.NoStoreDelegateException;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionGuidsSinceDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionWipeDelegate;
+import org.mozilla.gecko.sync.repositories.domain.ClientRecord;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+import org.mozilla.gecko.sync.repositories.domain.TabsRecord;
+
+import android.content.ContentProviderClient;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.RemoteException;
+
+public class FennecTabsRepository extends Repository {
+  private static final String LOG_TAG = "FennecTabsRepository";
+
+  protected final ClientsDataDelegate clientsDataDelegate;
+
+  public FennecTabsRepository(ClientsDataDelegate clientsDataDelegate) {
+    this.clientsDataDelegate = clientsDataDelegate;
+  }
+
+  /**
+   * Note that -- unlike most repositories -- this will only fetch Fennec's tabs,
+   * and only store tabs from other clients.
+   *
+   * It will never retrieve tabs from other clients, or store tabs for Fennec,
+   * unless you use {@link #fetch(String[], RepositorySessionFetchRecordsDelegate)}
+   * and specify an explicit GUID.
+   */
+  public class FennecTabsRepositorySession extends RepositorySession {
+    protected static final String LOG_TAG = "FennecTabsSession";
+
+    private final ContentProviderClient tabsProvider;
+    private final ContentProviderClient clientsProvider;
+
+    protected final RepoUtils.QueryHelper tabsHelper;
+
+    protected final ClientsDatabaseAccessor clientsDatabase;
+
+    protected ContentProviderClient getContentProvider(final Context context, final Uri uri) throws NoContentProviderException {
+      ContentProviderClient client = context.getContentResolver().acquireContentProviderClient(uri);
+      if (client == null) {
+        throw new NoContentProviderException(uri);
+      }
+      return client;
+    }
+
+    protected void releaseProviders() {
+      try {
+        clientsProvider.release();
+      } catch (Exception e) {}
+      try {
+        tabsProvider.release();
+      } catch (Exception e) {}
+      clientsDatabase.close();
+    }
+
+    public FennecTabsRepositorySession(Repository repository, Context context) throws NoContentProviderException {
+      super(repository);
+      clientsProvider = getContentProvider(context, BrowserContractHelpers.CLIENTS_CONTENT_URI);
+      try {
+        tabsProvider = getContentProvider(context, BrowserContractHelpers.TABS_CONTENT_URI);
+      } catch (NoContentProviderException e) {
+        clientsProvider.release();
+        throw e;
+      } catch (Exception e) {
+        clientsProvider.release();
+        // Oh, Java.
+        throw new RuntimeException(e);
+      }
+
+      tabsHelper = new RepoUtils.QueryHelper(context, BrowserContractHelpers.TABS_CONTENT_URI, LOG_TAG);
+      clientsDatabase = new ClientsDatabaseAccessor(context);
+    }
+
+    @Override
+    public void abort() {
+      releaseProviders();
+      super.abort();
+    }
+
+    @Override
+    public void finish(final RepositorySessionFinishDelegate delegate) throws InactiveSessionException {
+      releaseProviders();
+      super.finish(delegate);
+    }
+
+    // Default parameters for local data: local client has null GUID. Override
+    // these to test against non-live data.
+    protected String localClientSelection() {
+      return BrowserContract.Tabs.CLIENT_GUID + " IS NULL";
+    }
+
+    protected String[] localClientSelectionArgs() {
+      return null;
+    }
+
+    @Override
+    public void guidsSince(final long timestamp,
+                           final RepositorySessionGuidsSinceDelegate delegate) {
+      // Bug 783692: Now that Bug 730039 has landed, we could implement this,
+      // but it's not a priority since it's not used (yet).
+      Logger.warn(LOG_TAG, "Not returning anything from guidsSince.");
+      delegateQueue.execute(new Runnable() {
+        @Override
+        public void run() {
+          delegate.onGuidsSinceSucceeded(new String[] {});
+        }
+      });
+    }
+
+    @Override
+    public void fetchSince(final long timestamp,
+                           final RepositorySessionFetchRecordsDelegate delegate) {
+      if (tabsProvider == null) {
+        throw new IllegalArgumentException("tabsProvider was null.");
+      }
+      if (tabsHelper == null) {
+        throw new IllegalArgumentException("tabsHelper was null.");
+      }
+
+      final String positionAscending = BrowserContract.Tabs.POSITION + " ASC";
+
+      final String localClientSelection = localClientSelection();
+      final String[] localClientSelectionArgs = localClientSelectionArgs();
+
+      final Runnable command = new Runnable() {
+        @Override
+        public void run() {
+          // We fetch all local tabs (since the record must contain them all)
+          // but only process the record if the timestamp is sufficiently
+          // recent, or if the client data has been modified.
+          try {
+            final Cursor cursor = tabsHelper.safeQuery(tabsProvider, ".fetchSince()", null,
+                localClientSelection, localClientSelectionArgs, positionAscending);
+            try {
+              final String localClientGuid = clientsDataDelegate.getAccountGUID();
+              final String localClientName = clientsDataDelegate.getClientName();
+              final TabsRecord tabsRecord = FennecTabsRepository.tabsRecordFromCursor(cursor, localClientGuid, localClientName);
+
+              if (tabsRecord.lastModified >= timestamp ||
+                  clientsDataDelegate.getLastModifiedTimestamp() >= timestamp) {
+                delegate.onFetchedRecord(tabsRecord);
+              }
+            } finally {
+              cursor.close();
+            }
+          } catch (Exception e) {
+            delegate.onFetchFailed(e, null);
+            return;
+          }
+          delegate.onFetchCompleted(now());
+        }
+      };
+
+      delegateQueue.execute(command);
+    }
+
+    @Override
+    public void fetch(final String[] guids,
+                      final RepositorySessionFetchRecordsDelegate delegate) {
+      // Bug 783692: Now that Bug 730039 has landed, we could implement this,
+      // but it's not a priority since it's not used (yet).
+      Logger.warn(LOG_TAG, "Not returning anything from fetch");
+      delegateQueue.execute(new Runnable() {
+        @Override
+        public void run() {
+          delegate.onFetchCompleted(now());
+        }
+      });
+    }
+
+    @Override
+    public void fetchAll(final RepositorySessionFetchRecordsDelegate delegate) {
+      fetchSince(0, delegate);
+    }
+
+    private static final String TABS_CLIENT_GUID_IS = BrowserContract.Tabs.CLIENT_GUID + " = ?";
+    private static final String CLIENT_GUID_IS = BrowserContract.Clients.GUID + " = ?";
+
+    @Override
+    public void store(final Record record) throws NoStoreDelegateException {
+      if (delegate == null) {
+        Logger.warn(LOG_TAG, "No store delegate.");
+        throw new NoStoreDelegateException();
+      }
+      if (record == null) {
+        Logger.error(LOG_TAG, "Record sent to store was null");
+        throw new IllegalArgumentException("Null record passed to FennecTabsRepositorySession.store().");
+      }
+      if (!(record instanceof TabsRecord)) {
+        Logger.error(LOG_TAG, "Can't store anything but a TabsRecord");
+        throw new IllegalArgumentException("Non-TabsRecord passed to FennecTabsRepositorySession.store().");
+      }
+      final TabsRecord tabsRecord = (TabsRecord) record;
+
+      Runnable command = new Runnable() {
+        @Override
+        public void run() {
+          Logger.debug(LOG_TAG, "Storing tabs for client " + tabsRecord.guid);
+          if (!isActive()) {
+            delegate.onRecordStoreFailed(new InactiveSessionException(null), record.guid);
+            return;
+          }
+          if (tabsRecord.guid == null) {
+            delegate.onRecordStoreFailed(new RuntimeException("Can't store record with null GUID."), record.guid);
+            return;
+          }
+
+          try {
+            // This is nice and easy: we *always* store.
+            final String[] selectionArgs = new String[] { tabsRecord.guid };
+            if (tabsRecord.deleted) {
+              try {
+                Logger.debug(LOG_TAG, "Clearing entry for client " + tabsRecord.guid);
+                clientsProvider.delete(BrowserContractHelpers.CLIENTS_CONTENT_URI,
+                                       CLIENT_GUID_IS,
+                                       selectionArgs);
+                delegate.onRecordStoreSucceeded(record.guid);
+              } catch (Exception e) {
+                delegate.onRecordStoreFailed(e, record.guid);
+              }
+              return;
+            }
+
+            // If it exists, update the client record; otherwise insert.
+            final ContentValues clientsCV = tabsRecord.getClientsContentValues();
+
+            final ClientRecord clientRecord = clientsDatabase.fetchClient(tabsRecord.guid);
+            if (null != clientRecord) {
+                // Null is an acceptable device type.
+                clientsCV.put(Clients.DEVICE_TYPE, clientRecord.type);
+            }
+
+            Logger.debug(LOG_TAG, "Updating clients provider.");
+            final int updated = clientsProvider.update(BrowserContractHelpers.CLIENTS_CONTENT_URI,
+                clientsCV,
+                CLIENT_GUID_IS,
+                selectionArgs);
+            if (0 == updated) {
+              clientsProvider.insert(BrowserContractHelpers.CLIENTS_CONTENT_URI, clientsCV);
+            }
+
+            // Now insert tabs.
+            final ContentValues[] tabsArray = tabsRecord.getTabsContentValues();
+            Logger.debug(LOG_TAG, "Inserting " + tabsArray.length + " tabs for client " + tabsRecord.guid);
+
+            tabsProvider.delete(BrowserContractHelpers.TABS_CONTENT_URI, TABS_CLIENT_GUID_IS, selectionArgs);
+            final int inserted = tabsProvider.bulkInsert(BrowserContractHelpers.TABS_CONTENT_URI, tabsArray);
+            Logger.trace(LOG_TAG, "Inserted: " + inserted);
+
+            delegate.onRecordStoreSucceeded(record.guid);
+          } catch (Exception e) {
+            Logger.warn(LOG_TAG, "Error storing tabs.", e);
+            delegate.onRecordStoreFailed(e, record.guid);
+          }
+        }
+      };
+
+      storeWorkQueue.execute(command);
+    }
+
+    @Override
+    public void wipe(RepositorySessionWipeDelegate delegate) {
+      try {
+        tabsProvider.delete(BrowserContractHelpers.TABS_CONTENT_URI, null, null);
+        clientsProvider.delete(BrowserContractHelpers.CLIENTS_CONTENT_URI, null, null);
+      } catch (RemoteException e) {
+        Logger.warn(LOG_TAG, "Got RemoteException in wipe.", e);
+        delegate.onWipeFailed(e);
+        return;
+      }
+      delegate.onWipeSucceeded();
+    }
+  }
+
+  @Override
+  public void createSession(RepositorySessionCreationDelegate delegate,
+                            Context context) {
+    try {
+      final FennecTabsRepositorySession session = new FennecTabsRepositorySession(this, context);
+      delegate.onSessionCreated(session);
+    } catch (Exception e) {
+      delegate.onSessionCreateFailed(e);
+    }
+  }
+
+  /**
+   * Extract a <code>TabsRecord</code> from a cursor.
+   * <p>
+   * Caller is responsible for creating and closing cursor. Each row of the
+   * cursor should be an individual tab record.
+   * <p>
+   * The extracted tabs record has the given client GUID and client name.
+   *
+   * @param cursor
+   *          to inspect.
+   * @param clientGuid
+   *          returned tabs record will have this client GUID.
+   * @param clientName
+   *          returned tabs record will have this client name.
+   * @return <code>TabsRecord</code> instance.
+   */
+  public static TabsRecord tabsRecordFromCursor(final Cursor cursor, final String clientGuid, final String clientName) {
+    final String collection = "tabs";
+    final TabsRecord record = new TabsRecord(clientGuid, collection, 0, false);
+    record.tabs = new ArrayList<Tab>();
+    record.clientName = clientName;
+
+    record.androidID = -1;
+    record.deleted = false;
+
+    record.lastModified = 0;
+
+    int position = cursor.getPosition();
+    try {
+      cursor.moveToFirst();
+      while (!cursor.isAfterLast()) {
+        final Tab tab = Tab.fromCursor(cursor);
+        record.tabs.add(tab);
+
+        if (tab.lastUsed > record.lastModified) {
+          record.lastModified = tab.lastUsed;
+        }
+
+        cursor.moveToNext();
+      }
+    } finally {
+      cursor.moveToPosition(position);
+    }
+
+    return record;
+  }
+
+  /**
+   * Deletes all non-local clients and their associated remote tabs.
+   */
+  public static void deleteNonLocalClientsAndTabs(Context context) {
+    final String nonLocalClientSelection = BrowserContract.Clients.GUID + " IS NOT NULL";
+
+    ContentProviderClient clientsProvider = context.getContentResolver()
+            .acquireContentProviderClient(BrowserContractHelpers.CLIENTS_CONTENT_URI);
+    if (clientsProvider == null) {
+        Logger.warn(LOG_TAG, "Unable to create clientsProvider!");
+        return;
+    }
+
+    try {
+      Logger.info(LOG_TAG, "Clearing all non-local clients and their associated remote tabs for default profile.");
+      clientsProvider.delete(BrowserContractHelpers.CLIENTS_CONTENT_URI, nonLocalClientSelection, null);
+    } catch (RemoteException e) {
+      Logger.warn(LOG_TAG, "Error while deleting", e);
+    } finally {
+      try {
+        clientsProvider.release();
+      } catch (Exception e) {
+        Logger.warn(LOG_TAG, "Got exception releasing clientsProvider!", e);
+      }
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/FormHistoryRepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/FormHistoryRepositorySession.java
new file mode 100644
index 000000000..9beafa712
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/FormHistoryRepositorySession.java
@@ -0,0 +1,723 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.Callable;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.db.BrowserContract.DeletedFormHistory;
+import org.mozilla.gecko.db.BrowserContract.FormHistory;
+import org.mozilla.gecko.sync.repositories.InactiveSessionException;
+import org.mozilla.gecko.sync.repositories.NoContentProviderException;
+import org.mozilla.gecko.sync.repositories.NoStoreDelegateException;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.RecordFilter;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.StoreTrackingRepositorySession;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionGuidsSinceDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionWipeDelegate;
+import org.mozilla.gecko.sync.repositories.domain.FormHistoryRecord;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+import android.content.ContentProviderClient;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.RemoteException;
+
+public class FormHistoryRepositorySession extends
+    StoreTrackingRepositorySession {
+  public static final String LOG_TAG = "FormHistoryRepoSess";
+
+  /**
+   * Number of records to insert in one batch.
+   */
+  public static final int INSERT_ITEM_THRESHOLD = 200;
+
+  private static final Uri FORM_HISTORY_CONTENT_URI = BrowserContractHelpers.FORM_HISTORY_CONTENT_URI;
+  private static final Uri DELETED_FORM_HISTORY_CONTENT_URI = BrowserContractHelpers.DELETED_FORM_HISTORY_CONTENT_URI;
+
+  public static class FormHistoryRepository extends Repository {
+
+    @Override
+    public void createSession(RepositorySessionCreationDelegate delegate,
+                              Context context) {
+      try {
+        final FormHistoryRepositorySession session = new FormHistoryRepositorySession(this, context);
+        delegate.onSessionCreated(session);
+      } catch (Exception e) {
+        delegate.onSessionCreateFailed(e);
+      }
+    }
+  }
+
+  protected final ContentProviderClient formsProvider;
+  protected final RepoUtils.QueryHelper regularHelper;
+  protected final RepoUtils.QueryHelper deletedHelper;
+
+  /**
+   * Acquire the content provider client.
+   * <p>
+   * The caller is responsible for releasing the client.
+   *
+   * @param context The application context.
+   * @return The <code>ContentProviderClient</code>.
+   * @throws NoContentProviderException
+   */
+  public static ContentProviderClient acquireContentProvider(final Context context)
+      throws NoContentProviderException {
+    Uri uri = BrowserContract.FORM_HISTORY_AUTHORITY_URI;
+    ContentProviderClient client = context.getContentResolver().acquireContentProviderClient(uri);
+    if (client == null) {
+      throw new NoContentProviderException(uri);
+    }
+    return client;
+  }
+
+  protected void releaseProviders() {
+    try {
+      if (formsProvider != null) {
+        formsProvider.release();
+      }
+    } catch (Exception e) {
+    }
+  }
+
+  // Only used for testing.
+  public ContentProviderClient getFormsProvider() {
+    return formsProvider;
+  }
+
+  public FormHistoryRepositorySession(Repository repository, Context context)
+      throws NoContentProviderException {
+    super(repository);
+    formsProvider = acquireContentProvider(context);
+    regularHelper = new RepoUtils.QueryHelper(context, BrowserContractHelpers.FORM_HISTORY_CONTENT_URI, LOG_TAG);
+    deletedHelper = new RepoUtils.QueryHelper(context, BrowserContractHelpers.DELETED_FORM_HISTORY_CONTENT_URI, LOG_TAG);
+  }
+
+  @Override
+  public void abort() {
+    releaseProviders();
+    super.abort();
+  }
+
+  @Override
+  public void finish(final RepositorySessionFinishDelegate delegate)
+      throws InactiveSessionException {
+    releaseProviders();
+    super.finish(delegate);
+  }
+
+  protected static final String[] GUID_COLUMNS = new String[] { FormHistory.GUID };
+
+  @Override
+  public void guidsSince(final long timestamp, final RepositorySessionGuidsSinceDelegate delegate) {
+    Runnable command = new Runnable() {
+      @Override
+      public void run() {
+        if (!isActive()) {
+          delegate.onGuidsSinceFailed(new InactiveSessionException(null));
+          return;
+        }
+
+        ArrayList<String> guids = new ArrayList<String>();
+
+        final long sharedEnd = now();
+        Cursor cur = null;
+        try {
+          cur = regularHelper.safeQuery(formsProvider, "", GUID_COLUMNS, regularBetween(timestamp, sharedEnd), null, null);
+          cur.moveToFirst();
+          while (!cur.isAfterLast()) {
+            guids.add(cur.getString(0));
+            cur.moveToNext();
+          }
+        } catch (RemoteException | NullCursorException e) {
+          delegate.onGuidsSinceFailed(e);
+          return;
+        } finally {
+          if (cur != null) {
+            cur.close();
+          }
+        }
+
+        try {
+          cur = deletedHelper.safeQuery(formsProvider, "", GUID_COLUMNS, deletedBetween(timestamp, sharedEnd), null, null);
+          cur.moveToFirst();
+          while (!cur.isAfterLast()) {
+            guids.add(cur.getString(0));
+            cur.moveToNext();
+          }
+        } catch (RemoteException | NullCursorException e) {
+          delegate.onGuidsSinceFailed(e);
+          return;
+        } finally {
+          if (cur != null) {
+            cur.close();
+          }
+        }
+
+        String guidsArray[] = guids.toArray(new String[guids.size()]);
+        delegate.onGuidsSinceSucceeded(guidsArray);
+      }
+    };
+    delegateQueue.execute(command);
+  }
+
+  protected static FormHistoryRecord retrieveDuringFetch(final Cursor cursor) {
+    // A simple and efficient way to distinguish two tables.
+    if (cursor.getColumnCount() == BrowserContractHelpers.FormHistoryColumns.length) {
+      return formHistoryRecordFromCursor(cursor);
+    } else {
+      return deletedFormHistoryRecordFromCursor(cursor);
+    }
+  }
+
+  protected static FormHistoryRecord formHistoryRecordFromCursor(final Cursor cursor) {
+    String guid = RepoUtils.getStringFromCursor(cursor, FormHistory.GUID);
+    String collection = "forms";
+    FormHistoryRecord record = new FormHistoryRecord(guid, collection, 0, false);
+
+    record.fieldName = RepoUtils.getStringFromCursor(cursor, FormHistory.FIELD_NAME);
+    record.fieldValue = RepoUtils.getStringFromCursor(cursor, FormHistory.VALUE);
+    record.androidID = RepoUtils.getLongFromCursor(cursor, FormHistory.ID);
+    record.lastModified = RepoUtils.getLongFromCursor(cursor, FormHistory.FIRST_USED) / 1000; // Convert microseconds to milliseconds.
+    record.deleted = false;
+
+    record.log(LOG_TAG);
+    return record;
+  }
+
+  protected static FormHistoryRecord deletedFormHistoryRecordFromCursor(final Cursor cursor) {
+    String guid = RepoUtils.getStringFromCursor(cursor, DeletedFormHistory.GUID);
+    String collection = "forms";
+    FormHistoryRecord record = new FormHistoryRecord(guid, collection, 0, false);
+
+    record.guid = RepoUtils.getStringFromCursor(cursor, DeletedFormHistory.GUID);
+    record.androidID = RepoUtils.getLongFromCursor(cursor, DeletedFormHistory.ID);
+    record.lastModified = RepoUtils.getLongFromCursor(cursor, DeletedFormHistory.TIME_DELETED);
+    record.deleted = true;
+
+    record.log(LOG_TAG);
+    return record;
+  }
+
+  protected static void fetchFromCursor(final Cursor cursor, final RecordFilter filter, final RepositorySessionFetchRecordsDelegate delegate)
+      throws NullCursorException {
+    Logger.debug(LOG_TAG, "Fetch from cursor");
+    if (cursor == null) {
+      throw new NullCursorException(null);
+    }
+    try {
+      if (!cursor.moveToFirst()) {
+        return;
+      }
+      while (!cursor.isAfterLast()) {
+        Record r = retrieveDuringFetch(cursor);
+        if (r != null) {
+          if (filter == null || !filter.excludeRecord(r)) {
+            Logger.trace(LOG_TAG, "Processing record " + r.guid);
+            delegate.onFetchedRecord(r);
+          } else {
+            Logger.debug(LOG_TAG, "Skipping filtered record " + r.guid);
+          }
+        }
+        cursor.moveToNext();
+      }
+    } finally {
+      Logger.trace(LOG_TAG, "Closing cursor after fetch.");
+      cursor.close();
+    }
+  }
+
+  protected void fetchHelper(final RepositorySessionFetchRecordsDelegate delegate, final long end, final List<Callable<Cursor>> cursorCallables) {
+    if (this.storeTracker == null) {
+      throw new IllegalStateException("Store tracker not yet initialized!");
+    }
+
+    final RecordFilter filter = this.storeTracker.getFilter();
+
+    Runnable command = new Runnable() {
+      @Override
+      public void run() {
+        if (!isActive()) {
+          delegate.onFetchFailed(new InactiveSessionException(null), null);
+          return;
+        }
+
+        for (Callable<Cursor> cursorCallable : cursorCallables) {
+          Cursor cursor = null;
+          try {
+            cursor = cursorCallable.call();
+            fetchFromCursor(cursor, filter, delegate); // Closes cursor.
+          } catch (Exception e) {
+            Logger.warn(LOG_TAG, "Exception during fetchHelper", e);
+            delegate.onFetchFailed(e, null);
+            return;
+          }
+        }
+
+        delegate.onFetchCompleted(end);
+      }
+    };
+
+    delegateQueue.execute(command);
+  }
+
+  protected static String regularBetween(long start, long end) {
+    return FormHistory.FIRST_USED + " >= " + Long.toString(1000 * start) + " AND " +
+           FormHistory.FIRST_USED + " <= " + Long.toString(1000 * end); // Microseconds.
+  }
+
+  protected static String deletedBetween(long start, long end) {
+    return DeletedFormHistory.TIME_DELETED + " >= " + Long.toString(start) + " AND " +
+           DeletedFormHistory.TIME_DELETED + " <= " + Long.toString(end); // Milliseconds.
+  }
+
+  @Override
+  public void fetchSince(final long timestamp, final RepositorySessionFetchRecordsDelegate delegate) {
+    Logger.trace(LOG_TAG, "Running fetchSince(" + timestamp + ").");
+
+    /*
+     * We need to be careful about the timestamp we complete the fetch with. If
+     * the first cursor Callable takes a year, then the second could return
+     * records long after the first was kicked off. To protect against this, we
+     * set an end point and bound our search.
+     */
+    final long sharedEnd = now();
+
+    Callable<Cursor> regularCallable = new Callable<Cursor>() {
+      @Override
+      public Cursor call() throws Exception {
+        return regularHelper.safeQuery(formsProvider, ".fetchSince(regular)", null, regularBetween(timestamp, sharedEnd), null, null);
+      }
+    };
+
+    Callable<Cursor> deletedCallable = new Callable<Cursor>() {
+      @Override
+      public Cursor call() throws Exception {
+        return deletedHelper.safeQuery(formsProvider, ".fetchSince(deleted)", null, deletedBetween(timestamp, sharedEnd), null, null);
+      }
+    };
+
+    @SuppressWarnings("unchecked")
+    List<Callable<Cursor>> callableCursors = Arrays.asList(regularCallable, deletedCallable);
+
+    fetchHelper(delegate, sharedEnd, callableCursors);
+  }
+
+  @Override
+  public void fetchAll(RepositorySessionFetchRecordsDelegate delegate) {
+    Logger.trace(LOG_TAG, "Running fetchAll.");
+    fetchSince(0, delegate);
+  }
+
+  @Override
+  public void fetch(final String[] guids, final RepositorySessionFetchRecordsDelegate delegate) {
+    Logger.trace(LOG_TAG, "Running fetch.");
+
+    final long sharedEnd = now();
+    final String where = RepoUtils.computeSQLInClause(guids.length, FormHistory.GUID);
+
+    Callable<Cursor> regularCallable = new Callable<Cursor>() {
+      @Override
+      public Cursor call() throws Exception {
+        String regularWhere = where + " AND " + FormHistory.FIRST_USED + " <= " + Long.toString(1000 * sharedEnd); // Microseconds.
+        return regularHelper.safeQuery(formsProvider, ".fetch(regular)", null, regularWhere, guids, null);
+      }
+    };
+
+    Callable<Cursor> deletedCallable = new Callable<Cursor>() {
+      @Override
+      public Cursor call() throws Exception {
+        String deletedWhere = where + " AND " + DeletedFormHistory.TIME_DELETED + " <= " + Long.toString(sharedEnd); // Milliseconds.
+        return deletedHelper.safeQuery(formsProvider, ".fetch(deleted)", null, deletedWhere, guids, null);
+      }
+    };
+
+    @SuppressWarnings("unchecked")
+    List<Callable<Cursor>> callableCursors = Arrays.asList(regularCallable, deletedCallable);
+
+    fetchHelper(delegate, sharedEnd, callableCursors);
+  }
+
+  protected static final String GUID_IS = FormHistory.GUID + " = ?";
+
+  protected Record findExistingRecordByGuid(String guid)
+      throws RemoteException, NullCursorException {
+    Cursor cursor = null;
+    try {
+      cursor = regularHelper.safeQuery(formsProvider, ".findExistingRecordByGuid(regular)",
+          null, GUID_IS, new String[] { guid }, null);
+      if (cursor.moveToFirst()) {
+        return formHistoryRecordFromCursor(cursor);
+      }
+    } finally {
+      if (cursor != null) {
+        cursor.close();
+      }
+    }
+
+    try {
+      cursor = deletedHelper.safeQuery(formsProvider, ".findExistingRecordByGuid(deleted)",
+          null, GUID_IS, new String[] { guid }, null);
+      if (cursor.moveToFirst()) {
+        return deletedFormHistoryRecordFromCursor(cursor);
+      }
+    } finally {
+      if (cursor != null) {
+        cursor.close();
+      }
+    }
+
+    return null;
+  }
+
+  protected Record findExistingRecordByPayload(Record rawRecord)
+      throws RemoteException, NullCursorException {
+    if (!rawRecord.deleted) {
+      FormHistoryRecord record = (FormHistoryRecord) rawRecord;
+      Cursor cursor = null;
+      try {
+        String where = FormHistory.FIELD_NAME + " = ? AND " + FormHistory.VALUE + " = ?";
+        cursor = regularHelper.safeQuery(formsProvider, ".findExistingRecordByPayload",
+            null, where, new String[] { record.fieldName, record.fieldValue }, null);
+        if (cursor.moveToFirst()) {
+          return formHistoryRecordFromCursor(cursor);
+        }
+      } finally {
+        if (cursor != null) {
+          cursor.close();
+        }
+      }
+    }
+
+    return null;
+  }
+
+  /**
+   * Called when a record with locally known GUID has been reported deleted by
+   * the server.
+   * <p>
+   * We purge the record's GUID from the regular and deleted tables.
+   *
+   * @param existingRecord
+   *          The local <code>Record</code> to replace.
+   * @throws RemoteException
+   */
+  protected void deleteExistingRecord(Record existingRecord) throws RemoteException {
+    if (existingRecord.deleted) {
+      formsProvider.delete(DELETED_FORM_HISTORY_CONTENT_URI, GUID_IS, new String[] { existingRecord.guid });
+      return;
+    }
+    formsProvider.delete(FORM_HISTORY_CONTENT_URI, GUID_IS, new String[] { existingRecord.guid });
+  }
+
+  protected static ContentValues contentValuesForRegularRecord(Record rawRecord) {
+    if (rawRecord.deleted) {
+      throw new IllegalArgumentException("Deleted record passed to insertNewRegularRecord.");
+    }
+
+    FormHistoryRecord record = (FormHistoryRecord) rawRecord;
+    ContentValues cv = new ContentValues();
+    cv.put(FormHistory.GUID, record.guid);
+    cv.put(FormHistory.FIELD_NAME, record.fieldName);
+    cv.put(FormHistory.VALUE, record.fieldValue);
+    cv.put(FormHistory.FIRST_USED, 1000 * record.lastModified); // Microseconds.
+    return cv;
+  }
+
+  protected final Object recordsBufferMonitor = new Object();
+  protected ArrayList<ContentValues> recordsBuffer = new ArrayList<ContentValues>();
+
+  protected void enqueueRegularRecord(Record record) {
+    synchronized (recordsBufferMonitor) {
+      if (recordsBuffer.size() >= INSERT_ITEM_THRESHOLD) {
+        // Insert the existing contents, then enqueue.
+        try {
+          flushInsertQueue();
+        } catch (Exception e) {
+          delegate.onRecordStoreFailed(e, record.guid);
+          return;
+        }
+      }
+      // Store the ContentValues, rather than the record.
+      recordsBuffer.add(contentValuesForRegularRecord(record));
+    }
+  }
+
+  // Should always be called from storeWorkQueue.
+  protected void flushInsertQueue() throws RemoteException {
+    synchronized (recordsBufferMonitor) {
+      if (recordsBuffer.size() > 0) {
+        final ContentValues[] outgoing = recordsBuffer.toArray(new ContentValues[recordsBuffer.size()]);
+        recordsBuffer = new ArrayList<ContentValues>();
+
+        if (outgoing == null || outgoing.length == 0) {
+          Logger.debug(LOG_TAG, "No form history items to insert; returning immediately.");
+          return;
+        }
+
+        long before = System.currentTimeMillis();
+        formsProvider.bulkInsert(FORM_HISTORY_CONTENT_URI, outgoing);
+        long after = System.currentTimeMillis();
+        Logger.debug(LOG_TAG, "Inserted " + outgoing.length + " form history items in (" + (after - before) + " milliseconds).");
+      }
+    }
+  }
+
+  @Override
+  public void storeDone() {
+    Runnable command = new Runnable() {
+      @Override
+      public void run() {
+        Logger.debug(LOG_TAG, "Checking for residual form history items to insert.");
+        try {
+          synchronized (recordsBufferMonitor) {
+            flushInsertQueue();
+          }
+          storeDone(now());
+        } catch (Exception e) {
+          // XXX TODO
+          delegate.onRecordStoreFailed(e, null);
+        }
+      }
+    };
+    storeWorkQueue.execute(command);
+  }
+
+  /**
+   * Called when a regular record with locally unknown GUID has been fetched
+   * from the server.
+   * <p>
+   * Since the record is regular, we insert it into the regular table.
+   *
+   * @param record The regular <code>Record</code> from the server.
+   * @throws RemoteException
+   */
+  protected void insertNewRegularRecord(Record record)
+      throws RemoteException {
+    enqueueRegularRecord(record);
+  }
+
+  /**
+   * Called when a regular record with has been fetched from the server and
+   * should replace an existing record.
+   * <p>
+   * We delete the existing record entirely, and then insert the new record into
+   * the regular table.
+   *
+   * @param toStore
+   *          The regular <code>Record</code> from the server.
+   * @param existingRecord
+   *          The local <code>Record</code> to replace.
+   * @throws RemoteException
+   */
+  protected void replaceExistingRecordWithRegularRecord(Record toStore, Record existingRecord)
+      throws RemoteException {
+    if (existingRecord.deleted) {
+      // Need two database operations -- purge from deleted table, insert into regular table.
+      deleteExistingRecord(existingRecord);
+      insertNewRegularRecord(toStore);
+      return;
+    }
+
+    final ContentValues cv = contentValuesForRegularRecord(toStore);
+    int updated = formsProvider.update(FORM_HISTORY_CONTENT_URI, cv, GUID_IS, new String[] { existingRecord.guid });
+    if (updated != 1) {
+      Logger.warn(LOG_TAG, "Expected to update 1 record with guid " + existingRecord.guid + " but updated " + updated + " records.");
+    }
+  }
+
+  @Override
+  public void store(Record rawRecord) throws NoStoreDelegateException {
+    if (delegate == null) {
+      Logger.warn(LOG_TAG, "No store delegate.");
+      throw new NoStoreDelegateException();
+    }
+    if (rawRecord == null) {
+      Logger.error(LOG_TAG, "Record sent to store was null");
+      throw new IllegalArgumentException("Null record passed to FormHistoryRepositorySession.store().");
+    }
+    if (!(rawRecord instanceof FormHistoryRecord)) {
+      Logger.error(LOG_TAG, "Can't store anything but a FormHistoryRecord");
+      throw new IllegalArgumentException("Non-FormHistoryRecord passed to FormHistoryRepositorySession.store().");
+    }
+    final FormHistoryRecord record = (FormHistoryRecord) rawRecord;
+
+    Runnable command = new Runnable() {
+      @Override
+      public void run() {
+        if (!isActive()) {
+          Logger.warn(LOG_TAG, "FormHistoryRepositorySession is inactive. Store failing.");
+          delegate.onRecordStoreFailed(new InactiveSessionException(null), record.guid);
+          return;
+        }
+
+        // TODO: lift these into the session.
+        // Temporary: this matches prior syncing semantics, in which only
+        // the relationship between the local and remote record is considered.
+        // In the future we'll track these two timestamps and use them to
+        // determine which records have changed, and thus process incoming
+        // records more efficiently.
+        long lastLocalRetrieval  = 0;      // lastSyncTimestamp?
+        long lastRemoteRetrieval = 0;      // TODO: adjust for clock skew.
+        boolean remotelyModified = record.lastModified > lastRemoteRetrieval;
+
+        Record existingRecord;
+        try {
+          // GUID matching only: deleted records don't have a payload with which to search.
+          existingRecord = findExistingRecordByGuid(record.guid);
+          if (record.deleted) {
+            if (existingRecord == null) {
+              // We're done. Don't bother with a callback. That can change later
+              // if we want it to.
+              Logger.trace(LOG_TAG, "Incoming record " + record.guid + " is deleted, and no local version. Bye!");
+              return;
+            }
+
+            if (existingRecord.deleted) {
+              Logger.trace(LOG_TAG, "Local record already deleted. Purging local.");
+              deleteExistingRecord(existingRecord);
+              return;
+            }
+
+            // Which one wins?
+            if (!remotelyModified) {
+              Logger.trace(LOG_TAG, "Ignoring deleted record from the past.");
+              return;
+            }
+
+            boolean locallyModified = existingRecord.lastModified > lastLocalRetrieval;
+            if (!locallyModified) {
+              Logger.trace(LOG_TAG, "Remote modified, local not. Deleting.");
+              deleteExistingRecord(existingRecord);
+              trackRecord(record);
+              delegate.onRecordStoreSucceeded(record.guid);
+              return;
+            }
+
+            Logger.trace(LOG_TAG, "Both local and remote records have been modified.");
+            if (record.lastModified > existingRecord.lastModified) {
+              Logger.trace(LOG_TAG, "Remote is newer, and deleted. Purging local.");
+              deleteExistingRecord(existingRecord);
+              trackRecord(record);
+              delegate.onRecordStoreSucceeded(record.guid);
+              return;
+            }
+
+            Logger.trace(LOG_TAG, "Remote is older, local is not deleted. Ignoring.");
+            if (!locallyModified) {
+              Logger.warn(LOG_TAG, "Inconsistency: old remote record is deleted, but local record not modified!");
+              // Ensure that this is tracked for upload.
+            }
+            return;
+          }
+          // End deletion logic.
+
+          // Now we're processing a non-deleted incoming record.
+          if (existingRecord == null) {
+            Logger.trace(LOG_TAG, "Looking up match for record " + record.guid);
+            existingRecord = findExistingRecordByPayload(record);
+          }
+
+          if (existingRecord == null) {
+            // The record is new.
+            Logger.trace(LOG_TAG, "No match. Inserting.");
+            insertNewRegularRecord(record);
+            trackRecord(record);
+            delegate.onRecordStoreSucceeded(record.guid);
+            return;
+          }
+
+          // We found a local duplicate.
+          Logger.trace(LOG_TAG, "Incoming record " + record.guid + " dupes to local record " + existingRecord.guid);
+
+          if (!RepoUtils.stringsEqual(record.guid, existingRecord.guid)) {
+            // We found a local record that does NOT have the same GUID -- keep the server's version.
+            Logger.trace(LOG_TAG, "Remote guid different from local guid. Storing to keep remote guid.");
+            replaceExistingRecordWithRegularRecord(record, existingRecord);
+            trackRecord(record);
+            delegate.onRecordStoreSucceeded(record.guid);
+            return;
+          }
+
+          // We found a local record that does have the same GUID -- check modification times.
+          boolean locallyModified = existingRecord.lastModified > lastLocalRetrieval;
+          if (!locallyModified) {
+            Logger.trace(LOG_TAG, "Remote modified, local not. Storing.");
+            replaceExistingRecordWithRegularRecord(record, existingRecord);
+            trackRecord(record);
+            delegate.onRecordStoreSucceeded(record.guid);
+            return;
+          }
+
+          Logger.trace(LOG_TAG, "Both local and remote records have been modified.");
+          if (record.lastModified > existingRecord.lastModified) {
+            Logger.trace(LOG_TAG, "Remote is newer, and not deleted. Storing.");
+            replaceExistingRecordWithRegularRecord(record, existingRecord);
+            trackRecord(record);
+            delegate.onRecordStoreSucceeded(record.guid);
+            return;
+          }
+
+          Logger.trace(LOG_TAG, "Remote is older, local is not deleted. Ignoring.");
+          if (!locallyModified) {
+            Logger.warn(LOG_TAG, "Inconsistency: old remote record is not deleted, but local record not modified!");
+          }
+          return;
+        } catch (Exception e) {
+          Logger.error(LOG_TAG, "Store failed for " + record.guid, e);
+          delegate.onRecordStoreFailed(e, record.guid);
+          return;
+        }
+      }
+    };
+
+    storeWorkQueue.execute(command);
+  }
+
+  /**
+   * Purge all data from the underlying databases.
+   */
+  public static void purgeDatabases(ContentProviderClient formsProvider)
+      throws RemoteException {
+    formsProvider.delete(FORM_HISTORY_CONTENT_URI, null, null);
+    formsProvider.delete(DELETED_FORM_HISTORY_CONTENT_URI, null, null);
+  }
+
+  @Override
+  public void wipe(final RepositorySessionWipeDelegate delegate) {
+    Runnable command = new Runnable() {
+      @Override
+      public void run() {
+        if (!isActive()) {
+          delegate.onWipeFailed(new InactiveSessionException(null));
+          return;
+        }
+
+        try {
+          Logger.debug(LOG_TAG, "Wiping form history and deleted form history...");
+          purgeDatabases(formsProvider);
+          Logger.debug(LOG_TAG, "Wiping form history and deleted form history... DONE");
+        } catch (Exception e) {
+          delegate.onWipeFailed(e);
+          return;
+        }
+
+        delegate.onWipeSucceeded();
+      }
+    };
+    storeWorkQueue.execute(command);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/PasswordsRepositorySession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/PasswordsRepositorySession.java
new file mode 100644
index 000000000..f7b7416df
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/PasswordsRepositorySession.java
@@ -0,0 +1,725 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.db.BrowserContract.DeletedColumns;
+import org.mozilla.gecko.db.BrowserContract.DeletedPasswords;
+import org.mozilla.gecko.db.BrowserContract.Passwords;
+import org.mozilla.gecko.sync.repositories.InactiveSessionException;
+import org.mozilla.gecko.sync.repositories.NoStoreDelegateException;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.RecordFilter;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.StoreTrackingRepositorySession;
+import org.mozilla.gecko.sync.repositories.android.RepoUtils.QueryHelper;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionGuidsSinceDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionWipeDelegate;
+import org.mozilla.gecko.sync.repositories.domain.PasswordRecord;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+import android.content.ContentProviderClient;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.RemoteException;
+
+public class PasswordsRepositorySession extends
+    StoreTrackingRepositorySession {
+
+  public static class PasswordsRepository extends Repository {
+    @Override
+    public void createSession(RepositorySessionCreationDelegate delegate,
+        Context context) {
+      PasswordsRepositorySession session = new PasswordsRepositorySession(PasswordsRepository.this, context);
+      final RepositorySessionCreationDelegate deferredCreationDelegate = delegate.deferredCreationDelegate();
+      deferredCreationDelegate.onSessionCreated(session);
+    }
+  }
+
+  private static final String LOG_TAG = "PasswordsRepoSession";
+  private static final String COLLECTION = "passwords";
+
+  private final RepoUtils.QueryHelper passwordsHelper;
+  private final RepoUtils.QueryHelper deletedPasswordsHelper;
+  private final ContentProviderClient passwordsProvider;
+
+  private final Context context;
+
+  public PasswordsRepositorySession(Repository repository, Context context) {
+    super(repository);
+    this.context = context;
+    this.passwordsHelper        = new QueryHelper(context, BrowserContractHelpers.PASSWORDS_CONTENT_URI, LOG_TAG);
+    this.deletedPasswordsHelper = new QueryHelper(context, BrowserContractHelpers.DELETED_PASSWORDS_CONTENT_URI, LOG_TAG);
+    this.passwordsProvider      = context.getContentResolver().acquireContentProviderClient(BrowserContract.PASSWORDS_AUTHORITY_URI);
+  }
+
+  private static final String[] GUID_COLS = new String[] { Passwords.GUID };
+  private static final String[] DELETED_GUID_COLS = new String[] { DeletedColumns.GUID };
+
+  private static final String WHERE_GUID_IS = Passwords.GUID + " = ?";
+  private static final String WHERE_DELETED_GUID_IS = DeletedPasswords.GUID + " = ?";
+
+  @Override
+  public void guidsSince(final long timestamp, final RepositorySessionGuidsSinceDelegate delegate) {
+    final Runnable guidsSinceRunnable = new Runnable() {
+      @Override
+      public void run() {
+
+        if (!isActive()) {
+          delegate.onGuidsSinceFailed(new InactiveSessionException(null));
+          return;
+        }
+
+        // Checks succeeded, now get GUIDs.
+        final List<String> guids = new ArrayList<String>();
+        try {
+          Logger.debug(LOG_TAG, "Fetching guidsSince from data table.");
+          final Cursor data = passwordsHelper.safeQuery(passwordsProvider, ".getGUIDsSince", GUID_COLS, dateModifiedWhere(timestamp), null, null);
+          try {
+            if (data.moveToFirst()) {
+              while (!data.isAfterLast()) {
+                guids.add(RepoUtils.getStringFromCursor(data, Passwords.GUID));
+                data.moveToNext();
+              }
+            }
+          } finally {
+            data.close();
+          }
+
+          // Fetch guids from deleted table.
+          Logger.debug(LOG_TAG, "Fetching guidsSince from deleted table.");
+          final Cursor deleted = deletedPasswordsHelper.safeQuery(passwordsProvider, ".getGUIDsSince", DELETED_GUID_COLS, dateModifiedWhereDeleted(timestamp), null, null);
+          try {
+            if (deleted.moveToFirst()) {
+              while (!deleted.isAfterLast()) {
+                guids.add(RepoUtils.getStringFromCursor(deleted, DeletedColumns.GUID));
+                deleted.moveToNext();
+              }
+            }
+          } finally {
+            deleted.close();
+          }
+        } catch (Exception e) {
+          Logger.error(LOG_TAG, "Exception in fetch.");
+          delegate.onGuidsSinceFailed(e);
+          return;
+        }
+        String[] guidStrings = new String[guids.size()];
+        delegate.onGuidsSinceSucceeded(guids.toArray(guidStrings));
+      }
+    };
+
+    delegateQueue.execute(guidsSinceRunnable);
+  }
+
+  @Override
+  public void fetchSince(final long timestamp, final RepositorySessionFetchRecordsDelegate delegate) {
+    final RecordFilter filter = this.storeTracker.getFilter();
+    final Runnable fetchSinceRunnable = new Runnable() {
+      @Override
+      public void run() {
+        if (!isActive()) {
+          delegate.onFetchFailed(new InactiveSessionException(null), null);
+          return;
+        }
+
+        final long end = now();
+        try {
+          // Fetch from data table.
+          Cursor data = passwordsHelper.safeQuery(passwordsProvider, ".fetchSince",
+                                                  getAllColumns(),
+                                                  dateModifiedWhere(timestamp),
+                                                  null, null);
+          if (!fetchAndCloseCursorDeleted(data, false, filter, delegate)) {
+            return;
+          }
+
+          // Fetch from deleted table.
+          Cursor deleted = deletedPasswordsHelper.safeQuery(passwordsProvider, ".fetchSince",
+                                                            getAllDeletedColumns(),
+                                                            dateModifiedWhereDeleted(timestamp),
+                                                            null, null);
+          if (!fetchAndCloseCursorDeleted(deleted, true, filter, delegate)) {
+            return;
+          }
+
+          // Success!
+          try {
+            delegate.onFetchCompleted(end);
+          } catch (Exception e) {
+            Logger.error(LOG_TAG, "Delegate fetch completed callback failed.", e);
+            // Don't call failure callback.
+            return;
+          }
+        } catch (Exception e) {
+          Logger.error(LOG_TAG, "Exception in fetch.");
+          delegate.onFetchFailed(e, null);
+        }
+      }
+    };
+
+    delegateQueue.execute(fetchSinceRunnable);
+  }
+
+  @Override
+  public void fetch(final String[] guids, final RepositorySessionFetchRecordsDelegate delegate) {
+    if (guids == null || guids.length < 1) {
+      Logger.error(LOG_TAG, "No guids to be fetched.");
+      final long end = now();
+      delegateQueue.execute(new Runnable() {
+        @Override
+        public void run() {
+          delegate.onFetchCompleted(end);
+        }
+      });
+      return;
+    }
+
+    // Checks succeeded, now fetch.
+    final RecordFilter filter = this.storeTracker.getFilter();
+    final Runnable fetchRunnable = new Runnable() {
+      @Override
+      public void run() {
+        if (!isActive()) {
+          delegate.onFetchFailed(new InactiveSessionException(null), null);
+          return;
+        }
+
+        final long end = now();
+        final String where = RepoUtils.computeSQLInClause(guids.length, "guid");
+        Logger.trace(LOG_TAG, "Fetch guids where: " + where);
+
+        try {
+          // Fetch records from data table.
+          Cursor data = passwordsHelper.safeQuery(passwordsProvider, ".fetch",
+                                                  getAllColumns(),
+                                                  where, guids, null);
+          if (!fetchAndCloseCursorDeleted(data, false, filter, delegate)) {
+            return;
+          }
+
+          // Fetch records from deleted table.
+          Cursor deleted = deletedPasswordsHelper.safeQuery(passwordsProvider, ".fetch",
+                                                            getAllDeletedColumns(),
+                                                            where, guids, null);
+          if (!fetchAndCloseCursorDeleted(deleted, true, filter, delegate)) {
+            return;
+          }
+
+          delegate.onFetchCompleted(end);
+
+        } catch (Exception e) {
+          Logger.error(LOG_TAG, "Exception in fetch.");
+          delegate.onFetchFailed(e, null);
+        }
+      }
+    };
+
+    delegateQueue.execute(fetchRunnable);
+  }
+
+  @Override
+  public void fetchAll(RepositorySessionFetchRecordsDelegate delegate) {
+    fetchSince(0, delegate);
+  }
+
+  @Override
+  public void store(final Record record) throws NoStoreDelegateException {
+    if (delegate == null) {
+      Logger.error(LOG_TAG, "No store delegate.");
+      throw new NoStoreDelegateException();
+    }
+    if (record == null) {
+      Logger.error(LOG_TAG, "Record sent to store was null.");
+      throw new IllegalArgumentException("Null record passed to PasswordsRepositorySession.store().");
+    }
+    if (!(record instanceof PasswordRecord)) {
+      Logger.error(LOG_TAG, "Can't store anything but a PasswordRecord.");
+      throw new IllegalArgumentException("Non-PasswordRecord passed to PasswordsRepositorySession.store().");
+    }
+
+    final PasswordRecord remoteRecord = (PasswordRecord) record;
+
+    final Runnable storeRunnable = new Runnable() {
+      @Override
+      public void run() {
+        if (!isActive()) {
+          Logger.warn(LOG_TAG, "RepositorySession is inactive. Store failing.");
+          delegate.onRecordStoreFailed(new InactiveSessionException(null), record.guid);
+          return;
+        }
+
+        final String guid = remoteRecord.guid;
+        if (guid == null) {
+          delegate.onRecordStoreFailed(new RuntimeException("Can't store record with null GUID."), record.guid);
+          return;
+        }
+
+        PasswordRecord existingRecord;
+        try {
+          existingRecord = retrieveByGUID(guid);
+        } catch (NullCursorException | RemoteException e) {
+          // Indicates a serious problem.
+          delegate.onRecordStoreFailed(e, record.guid);
+          return;
+        }
+
+        long lastLocalRetrieval  = 0;      // lastSyncTimestamp?
+        long lastRemoteRetrieval = 0;      // TODO: adjust for clock skew.
+        boolean remotelyModified = remoteRecord.lastModified > lastRemoteRetrieval;
+
+        // Check deleted state first.
+        if (remoteRecord.deleted) {
+          if (existingRecord == null) {
+            // Do nothing, record does not exist anyways.
+            Logger.info(LOG_TAG, "Incoming record " + remoteRecord.guid + " is deleted, and no local version.");
+            return;
+          }
+
+          if (existingRecord.deleted) {
+            // Record is already tracked as deleted. Delete from local.
+            storeRecordDeletion(existingRecord); // different from ABRepoSess.
+            Logger.info(LOG_TAG, "Incoming record " + remoteRecord.guid + " and local are both deleted.");
+            return;
+          }
+
+          // Which one wins?
+          if (!remotelyModified) {
+            trace("Ignoring deleted record from the past.");
+            return;
+          }
+
+          boolean locallyModified = existingRecord.lastModified > lastLocalRetrieval;
+          if (!locallyModified) {
+            trace("Remote modified, local not. Deleting.");
+            storeRecordDeletion(remoteRecord);
+            return;
+          }
+
+          trace("Both local and remote records have been modified.");
+          if (remoteRecord.lastModified > existingRecord.lastModified) {
+            trace("Remote is newer, and deleted. Deleting local.");
+            storeRecordDeletion(remoteRecord);
+            return;
+          }
+
+          trace("Remote is older, local is not deleted. Ignoring.");
+          if (!locallyModified) {
+            Logger.warn(LOG_TAG, "Inconsistency: old remote record is deleted, but local record not modified!");
+            // Ensure that this is tracked for upload.
+          }
+          return;
+        }
+        // End deletion logic.
+
+        // Validate the incoming record.
+        if (!remoteRecord.isValid()) {
+            Logger.warn(LOG_TAG, "Incoming record is invalid. Reporting store failed.");
+            delegate.onRecordStoreFailed(new RuntimeException("Can't store invalid password record."), record.guid);
+            return;
+        }
+
+        // Now we're processing a non-deleted incoming record.
+        if (existingRecord == null) {
+          trace("Looking up match for record " + remoteRecord.guid);
+          try {
+            existingRecord = findExistingRecord(remoteRecord);
+          } catch (RemoteException e) {
+            Logger.error(LOG_TAG, "Remote exception in findExistingRecord.");
+            delegate.onRecordStoreFailed(e, record.guid);
+          } catch (NullCursorException e) {
+            Logger.error(LOG_TAG, "Null cursor in findExistingRecord.");
+            delegate.onRecordStoreFailed(e, record.guid);
+          }
+        }
+
+        if (existingRecord == null) {
+          // The record is new.
+          trace("No match. Inserting.");
+          Logger.debug(LOG_TAG, "Didn't find matching record. Inserting.");
+          Record inserted = null;
+          try {
+            inserted = insert(remoteRecord);
+          } catch (RemoteException e) {
+            Logger.debug(LOG_TAG, "Record insert caused a RemoteException.");
+            delegate.onRecordStoreFailed(e, record.guid);
+            return;
+          }
+          trackRecord(inserted);
+          delegate.onRecordStoreSucceeded(inserted.guid);
+          return;
+        }
+
+        // We found a local dupe.
+        trace("Incoming record " + remoteRecord.guid + " dupes to local record " + existingRecord.guid);
+        Logger.debug(LOG_TAG, "remote " + remoteRecord.guid + " dupes to " + existingRecord.guid);
+
+        if (existingRecord.deleted && existingRecord.lastModified > remoteRecord.lastModified) {
+          Logger.debug(LOG_TAG, "Local deletion is newer, not storing remote record.");
+          return;
+        }
+
+        Record toStore = reconcileRecords(remoteRecord, existingRecord, lastRemoteRetrieval, lastLocalRetrieval);
+        if (toStore == null) {
+          Logger.debug(LOG_TAG, "Reconciling returned null. Not inserting a record.");
+          return;
+        }
+
+        // TODO: pass in timestamps?
+        Logger.debug(LOG_TAG, "Replacing " + existingRecord.guid + " with record " + toStore.guid);
+        Record replaced = null;
+        try {
+          replaced = replace(existingRecord, toStore);
+        } catch (RemoteException e) {
+          Logger.debug(LOG_TAG, "Record replace caused a RemoteException.");
+          delegate.onRecordStoreFailed(e, record.guid);
+          return;
+        }
+
+        // Note that we don't track records here; deciding that is the job
+        // of reconcileRecords.
+        Logger.debug(LOG_TAG, "Calling delegate callback with guid " + replaced.guid +
+                              "(" + replaced.androidID + ")");
+        delegate.onRecordStoreSucceeded(record.guid);
+        return;
+      }
+    };
+    storeWorkQueue.execute(storeRunnable);
+  }
+
+  @Override
+  public void wipe(final RepositorySessionWipeDelegate delegate) {
+    Logger.info(LOG_TAG, "Wiping " + BrowserContractHelpers.PASSWORDS_CONTENT_URI + ", " + BrowserContractHelpers.DELETED_PASSWORDS_CONTENT_URI);
+
+    Runnable wipeRunnable = new Runnable() {
+      @Override
+      public void run() {
+        if (!isActive()) {
+          delegate.onWipeFailed(new InactiveSessionException(null));
+          return;
+        }
+
+        // Wipe both data and deleted.
+        try {
+          context.getContentResolver().delete(BrowserContractHelpers.PASSWORDS_CONTENT_URI, null, null);
+          context.getContentResolver().delete(BrowserContractHelpers.DELETED_PASSWORDS_CONTENT_URI, null, null);
+        } catch (Exception e) {
+          delegate.onWipeFailed(e);
+          return;
+        }
+        delegate.onWipeSucceeded();
+      }
+    };
+    storeWorkQueue.execute(wipeRunnable);
+  }
+
+  @Override
+  public void abort() {
+    passwordsProvider.release();
+    super.abort();
+  }
+
+  @Override
+  public void finish(final RepositorySessionFinishDelegate delegate) throws InactiveSessionException {
+    passwordsProvider.release();
+    super.finish(delegate);
+  }
+
+  public void deleteGUID(String guid) throws RemoteException {
+    final String[] args = new String[] { guid };
+
+    int deleted = passwordsProvider.delete(BrowserContractHelpers.PASSWORDS_CONTENT_URI, WHERE_GUID_IS, args) +
+                  passwordsProvider.delete(BrowserContractHelpers.DELETED_PASSWORDS_CONTENT_URI, WHERE_DELETED_GUID_IS, args);
+    if (deleted == 1) {
+      return;
+    }
+    Logger.warn(LOG_TAG, "Unexpectedly deleted " + deleted + " rows for guid " + guid);
+  }
+
+  /**
+   * Insert record and return the record with its updated androidId set.
+   *
+   * @param record the record to insert.
+   * @return updated record.
+   * @throws RemoteException
+   */
+  public PasswordRecord insert(PasswordRecord record) throws RemoteException {
+    record.timePasswordChanged = now();
+    // TODO: are these necessary for Fennec autocomplete?
+    // record.timesUsed = 1;
+    // record.timeLastUsed = now();
+    ContentValues cv = getContentValues(record);
+    Uri insertedUri = passwordsProvider.insert(BrowserContractHelpers.PASSWORDS_CONTENT_URI, cv);
+    if (insertedUri == null) {
+      throw new RemoteException(); // Not much to be done here, save throw.
+    }
+    record.androidID = ContentUris.parseId(insertedUri);
+    return record;
+  }
+
+  public Record replace(Record origRecord, Record newRecord) throws RemoteException {
+    PasswordRecord newPasswordRecord = (PasswordRecord) newRecord;
+    PasswordRecord origPasswordRecord = (PasswordRecord) origRecord;
+    propagateTimes(newPasswordRecord, origPasswordRecord);
+    ContentValues cv = getContentValues(newPasswordRecord);
+
+    final String[] args = new String[] { origRecord.guid };
+
+    if (origRecord.deleted) {
+      // Purge from deleted table.
+      deleteGUID(origRecord.guid);
+      insert(newPasswordRecord);
+    } else {
+      int updated = context.getContentResolver().update(BrowserContractHelpers.PASSWORDS_CONTENT_URI, cv, WHERE_GUID_IS, args);
+      if (updated != 1) {
+        Logger.warn(LOG_TAG, "Unexpectedly updated " + updated + " rows for guid " + origPasswordRecord.guid);
+      }
+    }
+
+    return newRecord;
+  }
+
+  // When replacing a record, propagate the times.
+  private static void propagateTimes(PasswordRecord toRecord, PasswordRecord fromRecord) {
+    toRecord.timePasswordChanged = now();
+    toRecord.timeCreated  = fromRecord.timeCreated;
+    toRecord.timeLastUsed = fromRecord.timeLastUsed;
+    toRecord.timesUsed    = fromRecord.timesUsed;
+  }
+
+  private static String[] getAllColumns() {
+    return BrowserContractHelpers.PasswordColumns;
+  }
+
+  private static String[] getAllDeletedColumns() {
+    return BrowserContractHelpers.DeletedColumns;
+  }
+
+  /**
+   * Constructs the DB query string for entry age for deleted records.
+   *
+   * @param timestamp
+   * @return String DB query string for dates to fetch.
+   */
+  private static String dateModifiedWhereDeleted(long timestamp) {
+    return DeletedColumns.TIME_DELETED + " >= " + Long.toString(timestamp);
+  }
+
+  /**
+   * Constructs the DB query string for entry age for (undeleted) records.
+   *
+   * @param timestamp
+   * @return String DB query string for dates to fetch.
+   */
+  private static String dateModifiedWhere(long timestamp) {
+    return Passwords.TIME_PASSWORD_CHANGED + " >= " + Long.toString(timestamp);
+  }
+
+
+  /**
+   * Fetch from the cursor with the given parameters, invoking
+   * delegate callbacks and closing the cursor.
+   * Returns true on success, false if failure was signaled.
+   *
+   * @param cursor
+            fetch* cursor.
+   * @param deleted
+   *        true if using deleted table, false when using data table.
+   * @param delegate
+   *        FetchRecordsDelegate to process records.
+   */
+  private static boolean fetchAndCloseCursorDeleted(final Cursor cursor,
+                                                    final boolean deleted,
+                                                    final RecordFilter filter,
+                                                    final RepositorySessionFetchRecordsDelegate delegate) {
+    if (cursor == null) {
+      return true;
+    }
+
+    try {
+      while (cursor.moveToNext()) {
+        Record r = deleted ? deletedPasswordRecordFromCursor(cursor) : passwordRecordFromCursor(cursor);
+        if (r != null) {
+          if (filter == null || !filter.excludeRecord(r)) {
+            Logger.debug(LOG_TAG, "Processing record " + r.guid);
+            delegate.onFetchedRecord(r);
+          } else {
+            Logger.debug(LOG_TAG, "Skipping filtered record " + r.guid);
+          }
+        }
+      }
+    } catch (Exception e) {
+      Logger.error(LOG_TAG, "Exception in fetch.");
+      delegate.onFetchFailed(e, null);
+      return false;
+    } finally {
+      cursor.close();
+    }
+
+    return true;
+  }
+
+  private PasswordRecord retrieveByGUID(String guid) throws NullCursorException, RemoteException {
+    final String[] guidArg = new String[] { guid };
+
+    // Check data table.
+    final Cursor data = passwordsHelper.safeQuery(passwordsProvider, ".store", BrowserContractHelpers.PasswordColumns, WHERE_GUID_IS, guidArg, null);
+    try {
+      if (data.moveToFirst()) {
+        return passwordRecordFromCursor(data);
+      }
+    } finally {
+      data.close();
+    }
+
+    // Check deleted table.
+    final Cursor deleted = deletedPasswordsHelper.safeQuery(passwordsProvider, ".retrieveByGuid", BrowserContractHelpers.DeletedColumns, WHERE_DELETED_GUID_IS, guidArg, null);
+    try {
+      if (deleted.moveToFirst()) {
+        return deletedPasswordRecordFromCursor(deleted);
+      }
+    } finally {
+      deleted.close();
+    }
+
+    return null;
+  }
+
+  private static final String WHERE_RECORD_DATA =
+    Passwords.HOSTNAME        + " = ? AND " +
+    Passwords.HTTP_REALM      + " = ? AND " +
+    Passwords.FORM_SUBMIT_URL + " = ? AND " +
+    Passwords.USERNAME_FIELD  + " = ? AND " +
+    Passwords.PASSWORD_FIELD  + " = ?";
+
+  private PasswordRecord findExistingRecord(PasswordRecord record) throws NullCursorException, RemoteException {
+    PasswordRecord foundRecord = null;
+    Cursor cursor = null;
+    // Only check the data table.
+    // We can't encrypt username directly for query, so run a more general query and then filter.
+    final String[] whereArgs = new String[] {
+      record.hostname,
+      record.httpRealm,
+      record.formSubmitURL,
+      record.usernameField,
+      record.passwordField
+    };
+
+    try {
+      cursor = passwordsHelper.safeQuery(passwordsProvider, ".findRecord", getAllColumns(), WHERE_RECORD_DATA, whereArgs, null);
+      while (cursor.moveToNext()) {
+        foundRecord = passwordRecordFromCursor(cursor);
+
+        // We don't directly query for username because the
+        // username/password values are encrypted in the db.
+        // We don't have the keys for encrypting our query,
+        // so we run a more general query and then filter
+        // the returned records for a matching username.
+        Logger.pii(LOG_TAG, "Checking incoming [" + record.encryptedUsername + "] to [" + foundRecord.encryptedUsername + "]");
+        if (record.encryptedUsername.equals(foundRecord.encryptedUsername)) {
+          Logger.trace(LOG_TAG, "Found matching record: " + foundRecord.guid);
+          return foundRecord;
+        }
+      }
+    } finally {
+      if (cursor != null) {
+        cursor.close();
+      }
+    }
+    Logger.debug(LOG_TAG, "No matching records, returning null.");
+    return null;
+  }
+
+  private void storeRecordDeletion(Record record) {
+    try {
+      deleteGUID(record.guid);
+    } catch (RemoteException e) {
+      Logger.error(LOG_TAG, "RemoteException in password delete.");
+      delegate.onRecordStoreFailed(e, record.guid);
+      return;
+    }
+    delegate.onRecordStoreSucceeded(record.guid);
+  }
+
+  /**
+   * Make a PasswordRecord from a Cursor.
+   * @param cur
+   *        Cursor from query.
+   * @param deleted
+   *        true if creating a deleted Record, false if otherwise.
+   * @return
+   *        PasswordRecord populated from Cursor.
+   */
+  private static PasswordRecord passwordRecordFromCursor(Cursor cur) {
+    if (cur.isAfterLast()) {
+      return null;
+    }
+    String guid = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.GUID);
+    long lastModified = RepoUtils.getLongFromCursor(cur, BrowserContract.Passwords.TIME_PASSWORD_CHANGED);
+
+    PasswordRecord rec = new PasswordRecord(guid, COLLECTION, lastModified, false);
+    rec.id = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.ID);
+    rec.hostname = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.HOSTNAME);
+    rec.httpRealm = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.HTTP_REALM);
+    rec.formSubmitURL = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.FORM_SUBMIT_URL);
+    rec.usernameField = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.USERNAME_FIELD);
+    rec.passwordField = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.PASSWORD_FIELD);
+    rec.encType = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.ENC_TYPE);
+
+    // TODO decryption of username/password here (Bug 711636)
+    rec.encryptedUsername = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.ENCRYPTED_USERNAME);
+    rec.encryptedPassword = RepoUtils.getStringFromCursor(cur, BrowserContract.Passwords.ENCRYPTED_PASSWORD);
+
+    rec.timeCreated = RepoUtils.getLongFromCursor(cur, BrowserContract.Passwords.TIME_CREATED);
+    rec.timeLastUsed = RepoUtils.getLongFromCursor(cur, BrowserContract.Passwords.TIME_LAST_USED);
+    rec.timePasswordChanged = RepoUtils.getLongFromCursor(cur, BrowserContract.Passwords.TIME_PASSWORD_CHANGED);
+    rec.timesUsed = RepoUtils.getLongFromCursor(cur, BrowserContract.Passwords.TIMES_USED);
+    return rec;
+  }
+
+  private static PasswordRecord deletedPasswordRecordFromCursor(Cursor cur) {
+    if (cur.isAfterLast()) {
+      return null;
+    }
+    String guid = RepoUtils.getStringFromCursor(cur, DeletedColumns.GUID);
+    long lastModified = RepoUtils.getLongFromCursor(cur, DeletedColumns.TIME_DELETED);
+    PasswordRecord rec = new PasswordRecord(guid, COLLECTION, lastModified, true);
+    rec.androidID = RepoUtils.getLongFromCursor(cur, DeletedColumns.ID);
+    return rec;
+  }
+
+  private static ContentValues getContentValues(Record record) {
+    PasswordRecord rec = (PasswordRecord) record;
+
+    ContentValues cv = new ContentValues();
+    cv.put(BrowserContract.Passwords.GUID,            rec.guid);
+    cv.put(BrowserContract.Passwords.HOSTNAME,        rec.hostname);
+    cv.put(BrowserContract.Passwords.HTTP_REALM,      rec.httpRealm);
+    cv.put(BrowserContract.Passwords.FORM_SUBMIT_URL, rec.formSubmitURL);
+    cv.put(BrowserContract.Passwords.USERNAME_FIELD,  rec.usernameField);
+    cv.put(BrowserContract.Passwords.PASSWORD_FIELD,  rec.passwordField);
+
+    // TODO Do encryption of username/password here. Bug 711636
+    cv.put(BrowserContract.Passwords.ENC_TYPE,           rec.encType);
+    cv.put(BrowserContract.Passwords.ENCRYPTED_USERNAME, rec.encryptedUsername);
+    cv.put(BrowserContract.Passwords.ENCRYPTED_PASSWORD, rec.encryptedPassword);
+
+    cv.put(BrowserContract.Passwords.TIME_CREATED,          rec.timeCreated);
+    cv.put(BrowserContract.Passwords.TIME_LAST_USED,        rec.timeLastUsed);
+    cv.put(BrowserContract.Passwords.TIME_PASSWORD_CHANGED, rec.timePasswordChanged);
+    cv.put(BrowserContract.Passwords.TIMES_USED,            rec.timesUsed);
+    return cv;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/RepoUtils.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/RepoUtils.java
new file mode 100644
index 000000000..9c29953f8
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/RepoUtils.java
@@ -0,0 +1,290 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import android.content.ContentProviderClient;
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.net.Uri;
+import android.os.RemoteException;
+
+import org.json.simple.JSONArray;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonArrayJSONException;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.domain.ClientRecord;
+import org.mozilla.gecko.sync.repositories.domain.HistoryRecord;
+
+import java.io.IOException;
+
+public class RepoUtils {
+
+  private static final String LOG_TAG = "RepoUtils";
+
+  /**
+   * A helper class for monotonous SQL querying. Does timing and logging,
+   * offers a utility to throw on a null cursor.
+   *
+   * @author rnewman
+   *
+   */
+  public static class QueryHelper {
+    private final Context context;
+    private final Uri     uri;
+    private final String  tag;
+
+    public QueryHelper(Context context, Uri uri, String tag) {
+      this.context = context;
+      this.uri     = uri;
+      this.tag     = tag;
+    }
+
+    // For ContentProvider queries.
+    public Cursor safeQuery(String label, String[] projection,
+                            String selection, String[] selectionArgs, String sortOrder) throws NullCursorException {
+      long queryStart = android.os.SystemClock.uptimeMillis();
+      Cursor c = context.getContentResolver().query(uri, projection, selection, selectionArgs, sortOrder);
+      return checkAndLogCursor(label, queryStart, c);
+    }
+
+    public Cursor safeQuery(String[] projection, String selection, String[] selectionArgs, String sortOrder) throws NullCursorException {
+      return this.safeQuery(null, projection, selection, selectionArgs, sortOrder);
+    }
+
+    // For ContentProviderClient queries.
+    public Cursor safeQuery(ContentProviderClient client, String label, String[] projection,
+                            String selection, String[] selectionArgs, String sortOrder) throws NullCursorException, RemoteException {
+      long queryStart = android.os.SystemClock.uptimeMillis();
+      Cursor c = client.query(uri, projection, selection, selectionArgs, sortOrder);
+      return checkAndLogCursor(label, queryStart, c);
+    }
+
+    // For SQLiteOpenHelper queries.
+    public Cursor safeQuery(SQLiteDatabase db, String label, String table, String[] columns,
+                            String selection, String[] selectionArgs,
+                            String groupBy, String having, String orderBy, String limit) throws NullCursorException {
+      long queryStart = android.os.SystemClock.uptimeMillis();
+      Cursor c = db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy, limit);
+      return checkAndLogCursor(label, queryStart, c);
+    }
+
+    public Cursor safeQuery(SQLiteDatabase db, String label, String table, String[] columns,
+                            String selection, String[] selectionArgs) throws NullCursorException {
+      return safeQuery(db, label, table, columns, selection, selectionArgs, null, null, null, null);
+    }
+
+    private Cursor checkAndLogCursor(String label, long queryStart, Cursor c) throws NullCursorException {
+      long queryEnd = android.os.SystemClock.uptimeMillis();
+      String logLabel = (label == null) ? tag : (tag + label);
+      RepoUtils.queryTimeLogger(logLabel, queryStart, queryEnd);
+      return checkNullCursor(logLabel, c);
+    }
+
+    public Cursor checkNullCursor(String logLabel, Cursor cursor) throws NullCursorException {
+      if (cursor == null) {
+        Logger.error(tag, "Got null cursor exception in " + logLabel);
+        throw new NullCursorException(null);
+      }
+      return cursor;
+    }
+  }
+
+  /**
+   * This method exists because the behavior of <code>cur.getString()</code> is undefined
+   * when the value in the database is <code>NULL</code>.
+   * This method will return <code>null</code> in that case.
+   */
+  public static String optStringFromCursor(final Cursor cur, final String colId) {
+    final int col = cur.getColumnIndex(colId);
+    if (cur.isNull(col)) {
+      return null;
+    }
+    return cur.getString(col);
+  }
+
+  /**
+   * The behavior of this method when the value in the database is <code>NULL</code> is
+   * determined by the implementation of the {@link Cursor}.
+   */
+  public static String getStringFromCursor(final Cursor cur, final String colId) {
+    // TODO: getColumnIndexOrThrow?
+    // TODO: don't look up columns by name!
+    return cur.getString(cur.getColumnIndex(colId));
+  }
+
+  public static long getLongFromCursor(Cursor cur, String colId) {
+    return cur.getLong(cur.getColumnIndex(colId));
+  }
+
+  public static int getIntFromCursor(Cursor cur, String colId) {
+    return cur.getInt(cur.getColumnIndex(colId));
+  }
+
+  public static JSONArray getJSONArrayFromCursor(Cursor cur, String colId) {
+    String jsonArrayAsString = getStringFromCursor(cur, colId);
+    if (jsonArrayAsString == null) {
+      return new JSONArray();
+    }
+    try {
+      return ExtendedJSONObject.parseJSONArray(getStringFromCursor(cur, colId));
+    } catch (NonArrayJSONException e) {
+      Logger.error(LOG_TAG, "JSON parsing error for " + colId, e);
+      return null;
+    } catch (IOException e) {
+      Logger.error(LOG_TAG, "JSON parsing error for " + colId, e);
+      return null;
+    }
+  }
+
+  /**
+   * Return true if the provided URI is non-empty and acceptable to Fennec
+   * (i.e., not an undesirable scheme).
+   *
+   * This code is pilfered from Fennec, which pilfered from Places.
+   */
+  public static boolean isValidHistoryURI(String uri) {
+    if (uri == null || uri.length() == 0) {
+      return false;
+    }
+
+    // First, check the most common cases (HTTP, HTTPS) to avoid most of the work.
+    if (uri.startsWith("http:") || uri.startsWith("https:")) {
+      return true;
+    }
+
+    String scheme = Uri.parse(uri).getScheme();
+    if (scheme == null) {
+      return false;
+    }
+
+    // Now check for all bad things.
+    if (scheme.equals("about") ||
+        scheme.equals("imap") ||
+        scheme.equals("news") ||
+        scheme.equals("mailbox") ||
+        scheme.equals("moz-anno") ||
+        scheme.equals("view-source") ||
+        scheme.equals("chrome") ||
+        scheme.equals("resource") ||
+        scheme.equals("data") ||
+        scheme.equals("wyciwyg") ||
+        scheme.equals("javascript")) {
+      return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Create a HistoryRecord object from a cursor row.
+   *
+   * @return a HistoryRecord, or null if this row would produce
+   *         an invalid record (e.g., with a null URI or no visits).
+   */
+  public static HistoryRecord historyFromMirrorCursor(Cursor cur) {
+    final String guid = getStringFromCursor(cur, BrowserContract.SyncColumns.GUID);
+    if (guid == null) {
+      Logger.debug(LOG_TAG, "Skipping history record with null GUID.");
+      return null;
+    }
+
+    final String historyURI = getStringFromCursor(cur, BrowserContract.History.URL);
+    if (!isValidHistoryURI(historyURI)) {
+      Logger.debug(LOG_TAG, "Skipping history record " + guid + " with unwanted/invalid URI " + historyURI);
+      return null;
+    }
+
+    final long visitCount = getLongFromCursor(cur, BrowserContract.History.VISITS);
+    if (visitCount <= 0) {
+      Logger.debug(LOG_TAG, "Skipping history record " + guid + " with <= 0 visit count.");
+      return null;
+    }
+
+    final String collection = "history";
+    final long lastModified = getLongFromCursor(cur, BrowserContract.SyncColumns.DATE_MODIFIED);
+    final boolean deleted = getLongFromCursor(cur, BrowserContract.SyncColumns.IS_DELETED) == 1;
+
+    final HistoryRecord rec = new HistoryRecord(guid, collection, lastModified, deleted);
+
+    rec.androidID         = getLongFromCursor(cur, BrowserContract.History._ID);
+    rec.fennecDateVisited = getLongFromCursor(cur, BrowserContract.History.DATE_LAST_VISITED);
+    rec.fennecVisitCount  = visitCount;
+    rec.histURI           = historyURI;
+    rec.title             = getStringFromCursor(cur, BrowserContract.History.TITLE);
+
+    return logHistory(rec);
+  }
+
+  private static HistoryRecord logHistory(HistoryRecord rec) {
+    try {
+      Logger.debug(LOG_TAG, "Returning history record " + rec.guid + " (" + rec.androidID + ")");
+      Logger.debug(LOG_TAG, "> Visited:          " + rec.fennecDateVisited);
+      Logger.debug(LOG_TAG, "> Visits:           " + rec.fennecVisitCount);
+      if (Logger.LOG_PERSONAL_INFORMATION) {
+        Logger.pii(LOG_TAG, "> Title:            " + rec.title);
+        Logger.pii(LOG_TAG, "> URI:              " + rec.histURI);
+      }
+    } catch (Exception e) {
+      Logger.debug(LOG_TAG, "Exception logging history record " + rec, e);
+    }
+    return rec;
+  }
+
+  public static void logClient(ClientRecord rec) {
+    if (Logger.shouldLogVerbose(LOG_TAG)) {
+      Logger.trace(LOG_TAG, "Returning client record " + rec.guid + " (" + rec.androidID + ")");
+      Logger.trace(LOG_TAG, "Client Name:   " + rec.name);
+      Logger.trace(LOG_TAG, "Client Type:   " + rec.type);
+      Logger.trace(LOG_TAG, "Last Modified: " + rec.lastModified);
+      Logger.trace(LOG_TAG, "Deleted:       " + rec.deleted);
+    }
+  }
+
+  public static void queryTimeLogger(String methodCallingQuery, long queryStart, long queryEnd) {
+    long elapsedTime = queryEnd - queryStart;
+    Logger.debug(LOG_TAG, "Query timer: " + methodCallingQuery + " took " + elapsedTime + "ms.");
+  }
+
+  public static boolean stringsEqual(String a, String b) {
+    // Check for nulls
+    if (a == b) return true;
+    if (a == null && b != null) return false;
+    if (a != null && b == null) return false;
+
+    return a.equals(b);
+  }
+
+  public static String computeSQLLongInClause(long[] items, String field) {
+    final StringBuilder builder = new StringBuilder(field);
+    builder.append(" IN (");
+    int i = 0;
+    for (; i < items.length - 1; ++i) {
+      builder.append(items[i]);
+      builder.append(", ");
+    }
+    if (i < items.length) {
+      builder.append(items[i]);
+    }
+    builder.append(")");
+    return builder.toString();
+  }
+
+  public static String computeSQLInClause(int items, String field) {
+    final StringBuilder builder = new StringBuilder(field);
+    builder.append(" IN (");
+    int i = 0;
+    for (; i < items - 1; ++i) {
+      builder.append("?, ");
+    }
+    if (i < items) {
+      builder.append("?");
+    }
+    builder.append(")");
+    return builder.toString();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/VisitsHelper.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/VisitsHelper.java
new file mode 100644
index 000000000..9ba784759
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/android/VisitsHelper.java
@@ -0,0 +1,130 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.android;
+
+import android.content.ContentProviderClient;
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.RemoteException;
+import android.support.annotation.NonNull;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.db.BrowserContract.Visits;
+
+/**
+ * This class is used by History Sync code (see <code>AndroidBrowserHistoryDataAccessor</code> and <code>AndroidBrowserHistoryRepositorySession</code>,
+ * and provides utility functions for working with history visits. Primarily we're either inserting visits
+ * into local database based on data received from Sync, or we're preparing local visits for upload into Sync.
+ */
+public class VisitsHelper {
+    public static final boolean DEFAULT_IS_LOCAL_VALUE = false;
+    public static final String SYNC_TYPE_KEY = "type";
+    public static final String SYNC_DATE_KEY = "date";
+
+    /**
+     * Returns a list of ContentValues of visits ready for insertion for a provided History GUID.
+     * Visits must have data and type. See <code>getVisitContentValues</code>.
+     *
+     * @param guid History GUID to use when inserting visit records
+     * @param visits <code>JSONArray</code> list of (date, type) tuples for visits
+     * @return visits ready for insertion
+     */
+    public static ContentValues[] getVisitsContentValues(@NonNull String guid, @NonNull JSONArray visits) {
+        final ContentValues[] visitsToStore = new ContentValues[visits.size()];
+        final int visitCount = visits.size();
+
+        if (visitCount == 0) {
+            return visitsToStore;
+        }
+
+        for (int i = 0; i < visitCount; i++) {
+            visitsToStore[i] = getVisitContentValues(
+                    guid, (JSONObject) visits.get(i), DEFAULT_IS_LOCAL_VALUE);
+        }
+        return visitsToStore;
+    }
+
+    /**
+     * Maps up to <code>limit</code> visits for a given history GUID to an array of JSONObjects with "date" and "type" keys
+     *
+     * @param contentClient <code>ContentProviderClient</code> to use for querying Visits table
+     * @param guid History GUID for which to return visits
+     * @param limit Will return at most this number of visits
+     * @return <code>JSONArray</code> of all visits found for given History GUID
+     */
+    public static JSONArray getRecentHistoryVisitsForGUID(@NonNull ContentProviderClient contentClient,
+                                                          @NonNull String guid, int limit) throws RemoteException {
+        final JSONArray visits = new JSONArray();
+
+        final Cursor cursor = contentClient.query(
+                visitsUriWithLimit(limit),
+                new String[] {Visits.VISIT_TYPE, Visits.DATE_VISITED},
+                Visits.HISTORY_GUID + " = ?",
+                new String[] {guid}, null);
+        if (cursor == null) {
+            return visits;
+        }
+        try {
+            if (!cursor.moveToFirst()) {
+                return visits;
+            }
+
+            final int dateVisitedCol = cursor.getColumnIndexOrThrow(Visits.DATE_VISITED);
+            final int visitTypeCol = cursor.getColumnIndexOrThrow(Visits.VISIT_TYPE);
+
+            while (!cursor.isAfterLast()) {
+                insertTupleIntoVisitsUnchecked(visits,
+                        cursor.getLong(visitTypeCol),
+                        cursor.getLong(dateVisitedCol)
+                );
+                cursor.moveToNext();
+            }
+        } finally {
+            cursor.close();
+        }
+
+        return visits;
+    }
+
+    /**
+     * Constructs <code>ContentValues</code> object for a visit based on passed in parameters.
+     *
+     * @param visit <code>JSONObject</code> containing visit type and visit date keys for the visit
+     * @param guid History GUID with with to associate this visit
+     * @param isLocal Whether or not to mark this visit as local
+     * @return <code>ContentValues</code> with all visit values necessary for database insertion
+     * @throws IllegalArgumentException if visit object is missing date or type keys
+     */
+    public static ContentValues getVisitContentValues(@NonNull String guid, @NonNull JSONObject visit, boolean isLocal) {
+        if (!visit.containsKey(SYNC_DATE_KEY) || !visit.containsKey(SYNC_TYPE_KEY)) {
+            throw new IllegalArgumentException("Visit missing required keys");
+        }
+
+        final ContentValues cv = new ContentValues();
+        cv.put(Visits.HISTORY_GUID, guid);
+        cv.put(Visits.IS_LOCAL, isLocal ? Visits.VISIT_IS_LOCAL : Visits.VISIT_IS_REMOTE);
+        cv.put(Visits.VISIT_TYPE, (Long) visit.get(SYNC_TYPE_KEY));
+        cv.put(Visits.DATE_VISITED, (Long) visit.get(SYNC_DATE_KEY));
+
+        return cv;
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void insertTupleIntoVisitsUnchecked(@NonNull final JSONArray visits, @NonNull Long type, @NonNull Long date) {
+        final JSONObject visit = new JSONObject();
+        visit.put(SYNC_TYPE_KEY, type);
+        visit.put(SYNC_DATE_KEY, date);
+        visits.add(visit);
+    }
+
+    private static Uri visitsUriWithLimit(int limit) {
+        return BrowserContractHelpers.VISITS_CONTENT_URI
+                .buildUpon()
+                .appendQueryParameter("limit", Integer.toString(limit))
+                .build();
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferrableRepositorySessionCreationDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferrableRepositorySessionCreationDelegate.java
new file mode 100644
index 000000000..f292600e4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferrableRepositorySessionCreationDelegate.java
@@ -0,0 +1,41 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import org.mozilla.gecko.sync.ThreadPool;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+
+public abstract class DeferrableRepositorySessionCreationDelegate implements RepositorySessionCreationDelegate {
+  @Override
+  public RepositorySessionCreationDelegate deferredCreationDelegate() {
+    final RepositorySessionCreationDelegate self = this;
+    return new RepositorySessionCreationDelegate() {
+
+      // TODO: rewrite to use ExecutorService.
+      @Override
+      public void onSessionCreated(final RepositorySession session) {
+        ThreadPool.run(new Runnable() {
+          @Override
+          public void run() {
+            self.onSessionCreated(session);
+          }});
+      }
+
+      @Override
+      public void onSessionCreateFailed(final Exception ex) {
+        ThreadPool.run(new Runnable() {
+          @Override
+          public void run() {
+            self.onSessionCreateFailed(ex);
+          }});
+      }
+
+      @Override
+      public RepositorySessionCreationDelegate deferredCreationDelegate() {
+        return this;
+      }
+    };
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionBeginDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionBeginDelegate.java
new file mode 100644
index 000000000..1ccdcce19
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionBeginDelegate.java
@@ -0,0 +1,46 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+
+public class DeferredRepositorySessionBeginDelegate implements RepositorySessionBeginDelegate {
+  private final RepositorySessionBeginDelegate inner;
+  private final ExecutorService executor;
+  public DeferredRepositorySessionBeginDelegate(final RepositorySessionBeginDelegate inner, final ExecutorService executor) {
+    this.inner = inner;
+    this.executor = executor;
+  }
+
+  @Override
+  public void onBeginSucceeded(final RepositorySession session) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onBeginSucceeded(session);
+      }
+    });
+  }
+
+  @Override
+  public void onBeginFailed(final Exception ex) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onBeginFailed(ex);
+      }
+    });
+  }
+  
+  @Override
+  public RepositorySessionBeginDelegate deferredBeginDelegate(ExecutorService newExecutor) {
+    if (newExecutor == executor) {
+      return this;
+    }
+    throw new IllegalArgumentException("Can't re-defer this delegate.");
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionFetchRecordsDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionFetchRecordsDelegate.java
new file mode 100644
index 000000000..1178d9b5b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionFetchRecordsDelegate.java
@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+public class DeferredRepositorySessionFetchRecordsDelegate implements RepositorySessionFetchRecordsDelegate {
+  private final RepositorySessionFetchRecordsDelegate inner;
+  private final ExecutorService executor;
+  public DeferredRepositorySessionFetchRecordsDelegate(final RepositorySessionFetchRecordsDelegate inner, final ExecutorService executor) {
+    this.inner = inner;
+    this.executor = executor;
+  }
+
+  @Override
+  public void onFetchedRecord(final Record record) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+         inner.onFetchedRecord(record);
+      }
+    });
+  }
+
+  @Override
+  public void onFetchFailed(final Exception ex, final Record record) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onFetchFailed(ex, record);
+      }
+    });
+  }
+
+  @Override
+  public void onFetchCompleted(final long fetchEnd) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onFetchCompleted(fetchEnd);
+      }
+    });
+  }
+
+  @Override
+  public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService newExecutor) {
+    if (newExecutor == executor) {
+      return this;
+    }
+    throw new IllegalArgumentException("Can't re-defer this delegate.");
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionFinishDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionFinishDelegate.java
new file mode 100644
index 000000000..dbe7e4327
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionFinishDelegate.java
@@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+import org.mozilla.gecko.sync.repositories.RepositorySessionBundle;
+
+public class DeferredRepositorySessionFinishDelegate implements
+    RepositorySessionFinishDelegate {
+  protected final ExecutorService executor;
+  protected final RepositorySessionFinishDelegate inner;
+
+  public DeferredRepositorySessionFinishDelegate(RepositorySessionFinishDelegate inner,
+                                                 ExecutorService executor) {
+    this.executor = executor;
+    this.inner = inner;
+  }
+
+  @Override
+  public void onFinishSucceeded(final RepositorySession session,
+                                final RepositorySessionBundle bundle) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onFinishSucceeded(session, bundle);
+      }
+    });
+  }
+
+  @Override
+  public void onFinishFailed(final Exception ex) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onFinishFailed(ex);
+      }
+    });
+  }
+
+  @Override
+  public RepositorySessionFinishDelegate deferredFinishDelegate(ExecutorService newExecutor) {
+    if (newExecutor == executor) {
+      return this;
+    }
+    throw new IllegalArgumentException("Can't re-defer this delegate.");
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionStoreDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionStoreDelegate.java
new file mode 100644
index 000000000..2f659c733
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionStoreDelegate.java
@@ -0,0 +1,57 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+public class DeferredRepositorySessionStoreDelegate implements
+    RepositorySessionStoreDelegate {
+  protected final RepositorySessionStoreDelegate inner;
+  protected final ExecutorService                executor;
+
+  public DeferredRepositorySessionStoreDelegate(
+      RepositorySessionStoreDelegate inner, ExecutorService executor) {
+    this.inner = inner;
+    this.executor = executor;
+  }
+
+  @Override
+  public void onRecordStoreSucceeded(final String guid) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onRecordStoreSucceeded(guid);
+      }
+    });
+  }
+
+  @Override
+  public void onRecordStoreFailed(final Exception ex, final String guid) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onRecordStoreFailed(ex, guid);
+      }
+    });
+  }
+
+  @Override
+  public RepositorySessionStoreDelegate deferredStoreDelegate(ExecutorService newExecutor) {
+    if (newExecutor == executor) {
+      return this;
+    }
+    throw new IllegalArgumentException("Can't re-defer this delegate.");
+  }
+
+  @Override
+  public void onStoreCompleted(final long storeEnd) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onStoreCompleted(storeEnd);
+      }
+    });
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionBeginDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionBeginDelegate.java
new file mode 100644
index 000000000..f5853647f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionBeginDelegate.java
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+
+/**
+ * One of these two methods is guaranteed to be called after session.begin() is
+ * invoked (possibly during the invocation). The callback will be invoked prior
+ * to any other RepositorySession callbacks.
+ *
+ * @author rnewman
+ *
+ */
+public interface RepositorySessionBeginDelegate {
+  public void onBeginFailed(Exception ex);
+  public void onBeginSucceeded(RepositorySession session);
+  public RepositorySessionBeginDelegate deferredBeginDelegate(ExecutorService executor);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionCleanDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionCleanDelegate.java
new file mode 100644
index 000000000..139c561a0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionCleanDelegate.java
@@ -0,0 +1,12 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import org.mozilla.gecko.sync.repositories.Repository;
+
+public interface RepositorySessionCleanDelegate {
+  public void onCleaned(Repository repo);
+  public void onCleanFailed(Repository repo, Exception ex);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionCreationDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionCreationDelegate.java
new file mode 100644
index 000000000..6ad4991c3
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionCreationDelegate.java
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+
+// Used to provide the sessionCallback and storeCallback
+// mechanism to repository instances.
+public interface RepositorySessionCreationDelegate {
+  public void onSessionCreateFailed(Exception ex);
+  public void onSessionCreated(RepositorySession session);
+  public RepositorySessionCreationDelegate deferredCreationDelegate();
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionFetchRecordsDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionFetchRecordsDelegate.java
new file mode 100644
index 000000000..589a093dc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionFetchRecordsDelegate.java
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+public interface RepositorySessionFetchRecordsDelegate {
+  public void onFetchFailed(Exception ex, Record record);
+  public void onFetchedRecord(Record record);
+
+  /**
+   * Called when all records in this fetch have been returned.
+   *
+   * @param fetchEnd
+   *        A millisecond-resolution timestamp indicating the *remote* timestamp
+   *        at the end of the range of records. Usually this is the timestamp at
+   *        which the request was received.
+   *        E.g., the (normalized) value of the X-Weave-Timestamp header.
+   */
+  public void onFetchCompleted(final long fetchEnd);
+
+  public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionFinishDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionFinishDelegate.java
new file mode 100644
index 000000000..40296dd4f
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionFinishDelegate.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+import org.mozilla.gecko.sync.repositories.RepositorySessionBundle;
+
+public interface RepositorySessionFinishDelegate {
+  public void onFinishFailed(Exception ex);
+  public void onFinishSucceeded(RepositorySession session, RepositorySessionBundle bundle);
+  public RepositorySessionFinishDelegate deferredFinishDelegate(ExecutorService executor);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionGuidsSinceDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionGuidsSinceDelegate.java
new file mode 100644
index 000000000..4f82768f1
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionGuidsSinceDelegate.java
@@ -0,0 +1,10 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+public interface RepositorySessionGuidsSinceDelegate {
+  public void onGuidsSinceFailed(Exception ex);
+  public void onGuidsSinceSucceeded(String[] guids);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionStoreDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionStoreDelegate.java
new file mode 100644
index 000000000..01e44c3ae
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionStoreDelegate.java
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+/**
+ * These methods *must* be invoked asynchronously. Use deferredStoreDelegate if you
+ * need help doing this.
+ *
+ * @author rnewman
+ *
+ */
+public interface RepositorySessionStoreDelegate {
+  public void onRecordStoreFailed(Exception ex, String recordGuid);
+
+  // Called with a GUID when store has succeeded.
+  public void onRecordStoreSucceeded(String guid);
+  public void onStoreCompleted(long storeEnd);
+  public RepositorySessionStoreDelegate deferredStoreDelegate(ExecutorService executor);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionWipeDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionWipeDelegate.java
new file mode 100644
index 000000000..cc8830729
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionWipeDelegate.java
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.delegates;
+
+import java.util.concurrent.ExecutorService;
+
+public interface RepositorySessionWipeDelegate {
+  public void onWipeFailed(Exception ex);
+  public void onWipeSucceeded();
+  public RepositorySessionWipeDelegate deferredWipeDelegate(ExecutorService executor);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/BookmarkRecord.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/BookmarkRecord.java
new file mode 100644
index 000000000..27b8e7151
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/BookmarkRecord.java
@@ -0,0 +1,488 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URLEncoder;
+import java.util.Map;
+
+import org.json.simple.JSONArray;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonArrayJSONException;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.repositories.android.RepoUtils;
+
+/**
+ * Covers the fields used by all bookmark objects.
+ * @author rnewman
+ *
+ */
+public class BookmarkRecord extends Record {
+  public static final String PLACES_URI_PREFIX = "places:";
+
+  private static final String LOG_TAG = "BookmarkRecord";
+
+  public static final String COLLECTION_NAME = "bookmarks";
+  public static final long BOOKMARKS_TTL = -1; // Never ttl bookmarks.
+
+  public BookmarkRecord(String guid, String collection, long lastModified, boolean deleted) {
+    super(guid, collection, lastModified, deleted);
+    this.ttl = BOOKMARKS_TTL;
+  }
+  public BookmarkRecord(String guid, String collection, long lastModified) {
+    this(guid, collection, lastModified, false);
+  }
+  public BookmarkRecord(String guid, String collection) {
+    this(guid, collection, 0, false);
+  }
+  public BookmarkRecord(String guid) {
+    this(guid, COLLECTION_NAME, 0, false);
+  }
+  public BookmarkRecord() {
+    this(Utils.generateGuid(), COLLECTION_NAME, 0, false);
+  }
+
+  // Note: redundant accessors are evil. We're all grownups; let's just use
+  // public fields.
+  public String  title;
+  public String  bookmarkURI;
+  public String  description;
+  public String  keyword;
+  public String  parentID;
+  public String  parentName;
+  public long    androidParentID;
+  public String  type;
+  public long    androidPosition;
+
+  public JSONArray children;
+  public JSONArray tags;
+
+  @Override
+  public String toString() {
+    return "#<Bookmark " + guid + " (" + androidID + "), parent " +
+           parentID + "/" + androidParentID + "/" + parentName + ">";
+  }
+
+  // Oh God, this is terribly thread-unsafe. These record objects should be immutable.
+  @SuppressWarnings("unchecked")
+  protected JSONArray copyChildren() {
+    if (this.children == null) {
+      return null;
+    }
+    JSONArray children = new JSONArray();
+    children.addAll(this.children);
+    return children;
+  }
+
+  @SuppressWarnings("unchecked")
+  protected JSONArray copyTags() {
+    if (this.tags == null) {
+      return null;
+    }
+    JSONArray tags = new JSONArray();
+    tags.addAll(this.tags);
+    return tags;
+  }
+
+  @Override
+  public Record copyWithIDs(String guid, long androidID) {
+    BookmarkRecord out = new BookmarkRecord(guid, this.collection, this.lastModified, this.deleted);
+    out.androidID = androidID;
+    out.sortIndex = this.sortIndex;
+    out.ttl       = this.ttl;
+
+    // Copy BookmarkRecord fields.
+    out.title           = this.title;
+    out.bookmarkURI     = this.bookmarkURI;
+    out.description     = this.description;
+    out.keyword         = this.keyword;
+    out.parentID        = this.parentID;
+    out.parentName      = this.parentName;
+    out.androidParentID = this.androidParentID;
+    out.type            = this.type;
+    out.androidPosition = this.androidPosition;
+
+    out.children        = this.copyChildren();
+    out.tags            = this.copyTags();
+
+    return out;
+  }
+
+  public boolean isBookmark() {
+    if (type == null) {
+      return false;
+    }
+    return type.equals("bookmark");
+  }
+
+  public boolean isFolder() {
+    if (type == null) {
+      return false;
+    }
+    return type.equals("folder");
+  }
+
+  public boolean isLivemark() {
+    if (type == null) {
+      return false;
+    }
+    return type.equals("livemark");
+  }
+
+  public boolean isSeparator() {
+    if (type == null) {
+      return false;
+    }
+    return type.equals("separator");
+  }
+
+  public boolean isMicrosummary() {
+    if (type == null) {
+      return false;
+    }
+    return type.equals("microsummary");
+  }
+
+  public boolean isQuery() {
+    if (type == null) {
+      return false;
+    }
+    return type.equals("query");
+  }
+
+  /**
+   * Return true if this record should have the Sync fields
+   * of a bookmark, microsummary, or query.
+   */
+  private boolean isBookmarkIsh() {
+    if (type == null) {
+      return false;
+    }
+    return type.equals("bookmark") ||
+           type.equals("microsummary") ||
+           type.equals("query");
+  }
+
+  @Override
+  protected void initFromPayload(ExtendedJSONObject payload) {
+    this.type        = payload.getString("type");
+    this.title       = payload.getString("title");
+    this.description = payload.getString("description");
+    this.parentID    = payload.getString("parentid");
+    this.parentName  = payload.getString("parentName");
+
+    if (isFolder()) {
+      try {
+        this.children = payload.getArray("children");
+      } catch (NonArrayJSONException e) {
+        Logger.error(LOG_TAG, "Got non-array children in bookmark record " + this.guid, e);
+        // Let's see if we can recover later by using the parentid pointers.
+        this.children = new JSONArray();
+      }
+      return;
+    }
+
+    final String bmkUri = payload.getString("bmkUri");
+
+    // bookmark, microsummary, query.
+    if (isBookmarkIsh()) {
+      this.keyword = payload.getString("keyword");
+      try {
+        this.tags = payload.getArray("tags");
+      } catch (NonArrayJSONException e) {
+        Logger.warn(LOG_TAG, "Got non-array tags in bookmark record " + this.guid, e);
+        this.tags = new JSONArray();
+      }
+    }
+
+    if (isBookmark()) {
+      this.bookmarkURI = bmkUri;
+      return;
+    }
+
+    if (isLivemark()) {
+      String siteUri = payload.getString("siteUri");
+      String feedUri = payload.getString("feedUri");
+      this.bookmarkURI = encodeUnsupportedTypeURI(bmkUri,
+                                                  "siteUri", siteUri,
+                                                  "feedUri", feedUri);
+      return;
+    }
+    if (isQuery()) {
+      String queryId = payload.getString("queryId");
+      String folderName = payload.getString("folderName");
+      this.bookmarkURI = encodeUnsupportedTypeURI(bmkUri,
+                                                  "queryId", queryId,
+                                                  "folderName", folderName);
+      return;
+    }
+    if (isMicrosummary()) {
+      String generatorUri = payload.getString("generatorUri");
+      String staticTitle = payload.getString("staticTitle");
+      this.bookmarkURI = encodeUnsupportedTypeURI(bmkUri,
+                                                  "generatorUri", generatorUri,
+                                                  "staticTitle", staticTitle);
+      return;
+    }
+    if (isSeparator()) {
+      Object p = payload.get("pos");
+      if (p instanceof Long) {
+        this.androidPosition = (Long) p;
+      } else if (p instanceof String) {
+        try {
+          this.androidPosition = Long.parseLong((String) p, 10);
+        } catch (NumberFormatException e) {
+          return;
+        }
+      } else {
+        Logger.warn(LOG_TAG, "Unsupported position value " + p);
+        return;
+      }
+      String pos = String.valueOf(this.androidPosition);
+      this.bookmarkURI = encodeUnsupportedTypeURI(null, "pos", pos, null, null);
+      return;
+    }
+  }
+
+  @Override
+  protected void populatePayload(ExtendedJSONObject payload) {
+    putPayload(payload, "type", this.type);
+    putPayload(payload, "title", this.title);
+    putPayload(payload, "description", this.description);
+    putPayload(payload, "parentid", this.parentID);
+    putPayload(payload, "parentName", this.parentName);
+    putPayload(payload, "keyword", this.keyword);
+
+    if (isFolder()) {
+      payload.put("children", this.children);
+      return;
+    }
+
+    // bookmark, microsummary, query.
+    if (isBookmarkIsh()) {
+      if (isBookmark()) {
+        payload.put("bmkUri", bookmarkURI);
+      }
+
+      if (isQuery()) {
+        Map<String, String> parts = Utils.extractURIComponents(PLACES_URI_PREFIX, this.bookmarkURI);
+        putPayload(payload, "queryId", parts.get("queryId"), true);
+        putPayload(payload, "folderName", parts.get("folderName"), true);
+        putPayload(payload, "bmkUri", parts.get("uri"));
+        return;
+      }
+
+      if (this.tags != null) {
+        payload.put("tags", this.tags);
+      }
+
+      putPayload(payload, "keyword", this.keyword);
+      return;
+    }
+
+    if (isLivemark()) {
+      Map<String, String> parts = Utils.extractURIComponents(PLACES_URI_PREFIX, this.bookmarkURI);
+      putPayload(payload, "siteUri", parts.get("siteUri"));
+      putPayload(payload, "feedUri", parts.get("feedUri"));
+      return;
+    }
+    if (isMicrosummary()) {
+      Map<String, String> parts = Utils.extractURIComponents(PLACES_URI_PREFIX, this.bookmarkURI);
+      putPayload(payload, "generatorUri", parts.get("generatorUri"));
+      putPayload(payload, "staticTitle", parts.get("staticTitle"));
+      return;
+    }
+    if (isSeparator()) {
+      Map<String, String> parts = Utils.extractURIComponents(PLACES_URI_PREFIX, this.bookmarkURI);
+      String pos = parts.get("pos");
+      if (pos == null) {
+        return;
+      }
+      try {
+        payload.put("pos", Long.parseLong(pos, 10));
+      } catch (NumberFormatException e) {
+        return;
+      }
+      return;
+    }
+  }
+
+  private void trace(String s) {
+    Logger.trace(LOG_TAG, s);
+  }
+
+  @Override
+  public boolean equalPayloads(Object o) {
+    trace("Calling BookmarkRecord.equalPayloads.");
+    if (!(o instanceof BookmarkRecord)) {
+      return false;
+    }
+
+    BookmarkRecord other = (BookmarkRecord) o;
+    if (!super.equalPayloads(other)) {
+      return false;
+    }
+
+    if (!RepoUtils.stringsEqual(this.type, other.type)) {
+      return false;
+    }
+
+    // Check children.
+    if (isFolder() && (this.children != other.children)) {
+      trace("BookmarkRecord.equals: this folder: " + this.title + ", " + this.guid);
+      trace("BookmarkRecord.equals: other: " + other.title + ", " + other.guid);
+      if (this.children  == null &&
+          other.children != null) {
+        trace("Records differ: one children array is null.");
+        return false;
+      }
+      if (this.children  != null &&
+          other.children == null) {
+        trace("Records differ: one children array is null.");
+        return false;
+      }
+      if (this.children.size() != other.children.size()) {
+        trace("Records differ: children arrays differ in size (" +
+              this.children.size() + " vs. " + other.children.size() + ").");
+        return false;
+      }
+
+      for (int i = 0; i < this.children.size(); i++) {
+        String child = (String) this.children.get(i);
+        if (!other.children.contains(child)) {
+          trace("Records differ: child " + child + " not found.");
+          return false;
+        }
+      }
+    }
+
+    trace("Checking strings.");
+    return RepoUtils.stringsEqual(this.title, other.title)
+        && RepoUtils.stringsEqual(this.bookmarkURI, other.bookmarkURI)
+        && RepoUtils.stringsEqual(this.parentID, other.parentID)
+        && RepoUtils.stringsEqual(this.parentName, other.parentName)
+        && RepoUtils.stringsEqual(this.description, other.description)
+        && RepoUtils.stringsEqual(this.keyword, other.keyword)
+        && jsonArrayStringsEqual(this.tags, other.tags);
+  }
+
+  // TODO: two records can be congruent if their child lists are different.
+  @Override
+  public boolean congruentWith(Object o) {
+    return this.equalPayloads(o) &&
+           super.congruentWith(o);
+  }
+
+  // Converts two JSONArrays to strings and checks if they are the same.
+  // This is only useful for stuff like tags where we aren't actually
+  // touching the data there (and therefore ordering won't change)
+  private boolean jsonArrayStringsEqual(JSONArray a, JSONArray b) {
+    // Check for nulls
+    if (a == b) return true;
+    if (a == null && b != null) return false;
+    if (a != null && b == null) return false;
+    return RepoUtils.stringsEqual(a.toJSONString(), b.toJSONString());
+  }
+
+  /**
+   * URL-encode the provided string. If the input is null,
+   * the empty string is returned.
+   *
+   * @param in the string to encode.
+   * @return a URL-encoded version of the input.
+   */
+  protected static String encode(String in) {
+    if (in == null) {
+      return "";
+    }
+    try {
+      return URLEncoder.encode(in, "UTF-8");
+    } catch (UnsupportedEncodingException e) {
+      // Will never occur.
+      return null;
+    }
+  }
+
+  /**
+   * Take the provided URI and two parameters, constructing a URI like
+   *
+   *   places:uri=$uri&p1=$p1&p2=$p2
+   *
+   * null values in either parameter or value result in the parameter being omitted.
+   */
+  protected static String encodeUnsupportedTypeURI(String originalURI, String p1, String v1, String p2, String v2) {
+    StringBuilder b = new StringBuilder(PLACES_URI_PREFIX);
+    boolean previous = false;
+    if (originalURI != null) {
+      b.append("uri=");
+      b.append(encode(originalURI));
+      previous = true;
+    }
+    if (p1 != null && v1 != null) {
+      if (previous) {
+        b.append("&");
+      }
+      b.append(p1);
+      b.append("=");
+      b.append(encode(v1));
+      previous = true;
+    }
+    if (p2 != null && v2 != null) {
+      if (previous) {
+        b.append("&");
+      }
+      b.append(p2);
+      b.append("=");
+      b.append(encode(v2));
+      previous = true;
+    }
+    return b.toString();
+  }
+}
+
+
+/*
+// Bookmark:
+{cleartext:
+  {id:            "l7p2xqOTMMXw",
+   type:          "bookmark",
+   title:         "Your Flight Status",
+   parentName:    "mobile",
+   bmkUri:        "http: //www.flightstats.com/go/Mobile/flightStatusByFlightProcess.do;jsessionid=13A6C8DCC9592AF141A43349040262CE.web3: 8009?utm_medium=cpc&utm_campaign=co-op&utm_source=airlineInformationAndStatus&id=212492593",
+   tags:          [],
+   keyword:       null,
+   description:   null,
+   loadInSidebar: false,
+   parentid:      "mobile"},
+ data: {payload: {ciphertext: null},
+ id:         "l7p2xqOTMMXw",
+ sortindex:  107},
+ collection: "bookmarks"}
+
+// Folder:
+{cleartext:
+  {id:          "mobile",
+   type:        "folder",
+   parentName:  "",
+   title:       "mobile",
+   description: null,
+   children:    ["1ROdlTuIoddD", "3Z_bMIHPSZQ8", "4mSDUuOo2iVB", "8aEdE9IIrJVr",
+                 "9DzPTmkkZRDb", "Qwwb99HtVKsD", "s8tM36aGPKbq", "JMTi61hOO3JV",
+                 "JQUDk0wSvYip", "LmVH-J1r3HLz", "NhgQlC5ykYGW", "OVanevUUaqO2",
+                 "OtQVX0PMiWQj", "_GP5cF595iie", "fkRssjXSZDL3", "k7K_NwIA1Ya0",
+                 "raox_QGzvqh1", "vXYL-xHjK06k", "QKHKUN6Dm-xv", "pmN2dYWT2MJ_",
+                 "EVeO_J1SQiwL", "7N-qkepS7bec", "NIGa3ha-HVOE", "2Phv1I25wbuH",
+                 "TTSIAH1fV0VE", "WOmZ8PfH39Da", "gDTXNg4m1AJZ", "ayI30OZslHbO",
+                 "zSEs4O3n6CzQ", "oWTDR0gO2aWf", "wWHUoFaInXi9", "F7QTuVJDpsTM",
+                 "FIboggegplk-", "G4HWrT5nfRYS", "MHA7y9bupDdv", "T_Ldzmj0Ttte",
+                 "U9eYu3SxsE_U", "bk463Kl9IO_m", "brUfrqJjFNSR", "ccpawfWsD-bY",
+                 "l7p2xqOTMMXw", "o-nSDKtXYln7"],
+   parentid: "places"},
+ data:        {payload: {ciphertext: null},
+ id:          "mobile",
+ sortindex:   1000000},
+ collection: "bookmarks"}
+*/
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/BookmarkRecordFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/BookmarkRecordFactory.java
new file mode 100644
index 000000000..edf7b288c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/BookmarkRecordFactory.java
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+
+/**
+ * Turns CryptoRecords into BookmarkRecords.
+ *
+ * @author rnewman
+ *
+ */
+public class BookmarkRecordFactory extends RecordFactory {
+
+  @Override
+  public Record createRecord(Record record) {
+    BookmarkRecord r = new BookmarkRecord();
+    r.initFromEnvelope((CryptoRecord) record);
+    return r;
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/ClientRecord.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/ClientRecord.java
new file mode 100644
index 000000000..0c513a4a0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/ClientRecord.java
@@ -0,0 +1,231 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import org.json.simple.JSONArray;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonArrayJSONException;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.repositories.android.RepoUtils;
+
+public class ClientRecord extends Record {
+  private static final String LOG_TAG = "ClientRecord";
+
+  public static final String CLIENT_TYPE         = "mobile";
+  public static final String COLLECTION_NAME     = "clients";
+  public static final long CLIENTS_TTL = 21 * 24 * 60 * 60; // 21 days in seconds.
+  public static final String DEFAULT_CLIENT_NAME = "Default Name";
+
+  public static final String PROTOCOL_LEGACY_SYNC = "1.1";
+  public static final String PROTOCOL_FXA_SYNC = "1.5";
+
+  /**
+   * Each of these fields is 'owned' by the client it represents. For example,
+   * the "version" field is the Firefox version of that client; some time after
+   * that client upgrades, it'll upload a new record with its new version.
+   *
+   * The only exception is for commands. When a command is sent to a client, the
+   * sender will download its current record, append the command to the
+   * "commands" array, and reupload the record. After processing, the recipient
+   * will reupload its record with an empty commands array.
+   *
+   * Note that the version, then, will remain the version of the recipient, as
+   * with the other descriptive fields.
+   */
+  public String name = ClientRecord.DEFAULT_CLIENT_NAME;
+  public String type = ClientRecord.CLIENT_TYPE;
+  public String version = null;                      // Free-form string, optional.
+  public JSONArray commands;
+  public JSONArray protocols;
+
+  // Optional fields.
+  // See <https://github.com/mozilla-services/docs/blob/master/source/sync/objectformats.rst#user-content-clients>
+  // for full formats.
+  // If a value isn't known, the field is omitted.
+  public String formfactor;          // "phone", "largetablet", "smalltablet", "desktop", "laptop", "tv".
+  public String os;                  // One of "Android", "Darwin", "WINNT", "Linux", "iOS", "Firefox OS".
+  public String application;         // Display name, E.g., "Firefox Beta"
+  public String appPackage;          // E.g., "org.mozilla.firefox_beta"
+  public String device;              // E.g., "HTC One"
+  public String fxaDeviceId;         // E.g., "525b624eaaf1e40d21ec8997c3116ad8"
+
+  public ClientRecord(String guid, String collection, long lastModified, boolean deleted) {
+    super(guid, collection, lastModified, deleted);
+    this.ttl = CLIENTS_TTL;
+  }
+
+  public ClientRecord(String guid, String collection, long lastModified) {
+    this(guid, collection, lastModified, false);
+  }
+
+  public ClientRecord(String guid, String collection) {
+    this(guid, collection, 0, false);
+  }
+
+  public ClientRecord(String guid) {
+    this(guid, COLLECTION_NAME, 0, false);
+  }
+
+  public ClientRecord() {
+    this(Utils.generateGuid(), COLLECTION_NAME, 0, false);
+  }
+
+  @Override
+  protected void initFromPayload(ExtendedJSONObject payload) {
+    this.name = (String) payload.get("name");
+    this.type = (String) payload.get("type");
+    try {
+      this.version = (String) payload.get("version");
+    } catch (Exception e) {
+      // Oh well.
+    }
+
+    try {
+      commands = payload.getArray("commands");
+    } catch (NonArrayJSONException e) {
+      Logger.debug(LOG_TAG, "Got non-array commands in client record " + guid, e);
+      commands = null;
+    }
+
+    try {
+      protocols = payload.getArray("protocols");
+    } catch (NonArrayJSONException e) {
+      Logger.debug(LOG_TAG, "Got non-array protocols in client record " + guid, e);
+      protocols = null;
+    }
+
+    if (payload.containsKey("formfactor")) {
+      this.formfactor = payload.getString("formfactor");
+    }
+
+    if (payload.containsKey("os")) {
+      this.os = payload.getString("os");
+    }
+
+    if (payload.containsKey("application")) {
+      this.application = payload.getString("application");
+    }
+
+    if (payload.containsKey("appPackage")) {
+      this.appPackage = payload.getString("appPackage");
+    }
+
+    if (payload.containsKey("device")) {
+      this.device = payload.getString("device");
+    }
+
+    if (payload.containsKey("fxaDeviceId")) {
+      this.fxaDeviceId = payload.getString("fxaDeviceId");
+    }
+  }
+
+  @Override
+  protected void populatePayload(ExtendedJSONObject payload) {
+    putPayload(payload, "id",   this.guid);
+    putPayload(payload, "name", this.name);
+    putPayload(payload, "type", this.type);
+    putPayload(payload, "version", this.version);
+
+    if (this.commands != null) {
+      payload.put("commands",  this.commands);
+    }
+
+    if (this.protocols != null) {
+      payload.put("protocols",  this.protocols);
+    }
+
+    if (this.formfactor != null) {
+      payload.put("formfactor", this.formfactor);
+    }
+
+    if (this.os != null) {
+      payload.put("os", this.os);
+    }
+
+    if (this.application != null) {
+      payload.put("application", this.application);
+    }
+
+    if (this.appPackage != null) {
+      payload.put("appPackage", this.appPackage);
+    }
+
+    if (this.device != null) {
+      payload.put("device", this.device);
+    }
+
+    if (this.fxaDeviceId != null) {
+      payload.put("fxaDeviceId", this.fxaDeviceId);
+    }
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (!(o instanceof ClientRecord) || !super.equals(o)) {
+      return false;
+    }
+
+    return this.equalPayloads(o);
+  }
+
+  @Override
+  public int hashCode() {
+    return super.hashCode();
+  }
+
+  @Override
+  public boolean equalPayloads(Object o) {
+    if (!(o instanceof ClientRecord) || !super.equalPayloads(o)) {
+      return false;
+    }
+
+    // Don't compare versions, protocols, or other optional fields, no matter how much we might want to.
+    // They're not required by the spec.
+    ClientRecord other = (ClientRecord) o;
+    if (!RepoUtils.stringsEqual(other.name, this.name) ||
+        !RepoUtils.stringsEqual(other.type, this.type)) {
+      return false;
+    }
+    return true;
+  }
+
+  @Override
+  public Record copyWithIDs(String guid, long androidID) {
+    ClientRecord out = new ClientRecord(guid, this.collection, this.lastModified, this.deleted);
+    out.androidID = androidID;
+    out.sortIndex = this.sortIndex;
+    out.ttl       = this.ttl;
+
+    out.name = this.name;
+    out.type = this.type;
+    out.version = this.version;
+    out.protocols = this.protocols;
+
+    out.formfactor = this.formfactor;
+    out.os = this.os;
+    out.application = this.application;
+    out.appPackage = this.appPackage;
+    out.device = this.device;
+    out.fxaDeviceId = this.fxaDeviceId;
+
+    return out;
+  }
+
+/*
+Example record:
+
+{id:"relf31w7B4F1",
+ name:"marina_mac",
+ type:"mobile"
+ commands:[{"args":["bookmarks"],"command":"wipeEngine"},
+           {"args":["forms"],"command":"wipeEngine"},
+           {"args":["history"],"command":"wipeEngine"},
+           {"args":["passwords"],"command":"wipeEngine"},
+           {"args":["prefs"],"command":"wipeEngine"},
+           {"args":["tabs"],"command":"wipeEngine"},
+           {"args":["addons"],"command":"wipeEngine"}]}
+*/
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/ClientRecordFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/ClientRecordFactory.java
new file mode 100644
index 000000000..897d2859c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/ClientRecordFactory.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+
+public class ClientRecordFactory extends RecordFactory {
+  @Override
+  public Record createRecord(Record record) {
+    ClientRecord r = new ClientRecord();
+    r.initFromEnvelope((CryptoRecord) record);
+    return r;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/FormHistoryRecord.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/FormHistoryRecord.java
new file mode 100644
index 000000000..e7ca70cb4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/FormHistoryRecord.java
@@ -0,0 +1,139 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.repositories.android.RepoUtils;
+
+/**
+ * A FormHistoryRecord represents a saved form element.
+ *
+ * I map a <code>fieldName</code> string to a <code>value</code> string.
+ *
+ * @see "<a href='http://dxr.mozilla.org/services-central/source/services-central/services/sync/modules/engines/forms.js'>http://dxr.mozilla.org/services-central/source/services-central/services/sync/modules/engines/forms.js</a>."
+ */
+public class FormHistoryRecord extends Record {
+  private static final String LOG_TAG = "FormHistoryRecord";
+
+  public static final String  COLLECTION_NAME = "forms";
+  private static final String PAYLOAD_NAME    = "name";
+  private static final String PAYLOAD_VALUE   = "value";
+  public static final long FORMS_TTL = 3 * 365 * 24 * 60 * 60;   // Three years in seconds.
+
+  /**
+   * The name of the saved form field.
+   */
+  public String fieldName;
+
+  /**
+   * The value of the saved form field.
+   */
+  public String fieldValue;
+
+  public FormHistoryRecord(String guid, String collection, long lastModified, boolean deleted) {
+    super(guid, collection, lastModified, deleted);
+    this.ttl = FORMS_TTL;
+  }
+
+  public FormHistoryRecord(String guid, String collection, long lastModified) {
+    this(guid, collection, lastModified, false);
+  }
+
+  public FormHistoryRecord(String guid, String collection) {
+    this(guid, collection, 0, false);
+  }
+
+  public FormHistoryRecord(String guid) {
+    this(guid, COLLECTION_NAME, 0, false);
+  }
+
+  public FormHistoryRecord() {
+    this(Utils.generateGuid(), COLLECTION_NAME, 0, false);
+  }
+
+  @Override
+  public Record copyWithIDs(String guid, long androidID) {
+    FormHistoryRecord out = new FormHistoryRecord(guid, this.collection, this.lastModified, this.deleted);
+    out.androidID = androidID;
+    out.sortIndex = this.sortIndex;
+
+    // Copy FormHistoryRecord fields.
+    out.fieldName = this.fieldName;
+    out.fieldValue = this.fieldValue;
+
+    return out;
+  }
+
+  @Override
+  public void populatePayload(ExtendedJSONObject payload) {
+    putPayload(payload, PAYLOAD_NAME,  this.fieldName);
+    putPayload(payload, PAYLOAD_VALUE, this.fieldValue);
+  }
+
+  @Override
+  public void initFromPayload(ExtendedJSONObject payload) {
+    this.fieldName  = payload.getString(PAYLOAD_NAME);
+    this.fieldValue = payload.getString(PAYLOAD_VALUE);
+  }
+
+  /**
+   * We consider two form history records to be congruent if they represent the
+   * same form element regardless of times used.
+   */
+  @Override
+  public boolean congruentWith(Object o) {
+    if (!(o instanceof FormHistoryRecord)) {
+      return false;
+    }
+    FormHistoryRecord other = (FormHistoryRecord) o;
+    if (!super.congruentWith(other)) {
+      return false;
+    }
+    return RepoUtils.stringsEqual(this.fieldName, other.fieldName) &&
+           RepoUtils.stringsEqual(this.fieldValue, other.fieldValue);
+  }
+
+  @Override
+  public boolean equalPayloads(Object o) {
+    if (!(o instanceof FormHistoryRecord)) {
+      Logger.debug(LOG_TAG, "Not a FormHistoryRecord: " + o.getClass());
+      return false;
+    }
+    FormHistoryRecord other = (FormHistoryRecord) o;
+    if (!super.equalPayloads(other)) {
+      Logger.debug(LOG_TAG, "super.equalPayloads returned false.");
+      return false;
+    }
+
+    if (this.deleted) {
+      // FormHistoryRecords are equal if they are both deleted (which
+      // they are, since super.equalPayloads is true) and have the
+      // same GUID.
+      if (other.deleted) {
+        return RepoUtils.stringsEqual(this.guid, other.guid);
+      }
+      return false;
+    }
+
+    return RepoUtils.stringsEqual(this.fieldName,  other.fieldName) &&
+           RepoUtils.stringsEqual(this.fieldValue, other.fieldValue);
+  }
+
+  public FormHistoryRecord log(String logTag) {
+    try {
+      Logger.debug(logTag, "Returning form history record " + guid + " (" + androidID + ")");
+      Logger.debug(logTag, "> Last modified: " + lastModified);
+      if (Logger.LOG_PERSONAL_INFORMATION) {
+        Logger.pii(logTag, "> Field name:    " + fieldName);
+        Logger.pii(logTag, "> Field value:   " + fieldValue);
+      }
+    } catch (Exception e) {
+      Logger.debug(logTag, "Exception logging form history record " + this, e);
+    }
+    return this;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/HistoryRecord.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/HistoryRecord.java
new file mode 100644
index 000000000..94eae13a7
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/HistoryRecord.java
@@ -0,0 +1,217 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import java.util.HashMap;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonArrayJSONException;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.repositories.android.RepoUtils;
+
+/**
+ * Visits are in microsecond precision.
+ *
+ * @author rnewman
+ *
+ */
+public class HistoryRecord extends Record {
+  private static final String LOG_TAG = "HistoryRecord";
+
+  public static final String COLLECTION_NAME = "history";
+  public static final long HISTORY_TTL = 60 * 24 * 60 * 60; // 60 days in seconds.
+
+  public HistoryRecord(String guid, String collection, long lastModified, boolean deleted) {
+    super(guid, collection, lastModified, deleted);
+    this.ttl = HISTORY_TTL;
+  }
+  public HistoryRecord(String guid, String collection, long lastModified) {
+    this(guid, collection, lastModified, false);
+  }
+  public HistoryRecord(String guid, String collection) {
+    this(guid, collection, 0, false);
+  }
+  public HistoryRecord(String guid) {
+    this(guid, COLLECTION_NAME, 0, false);
+  }
+  public HistoryRecord() {
+    this(Utils.generateGuid(), COLLECTION_NAME, 0, false);
+  }
+
+  public String    title;
+  public String    histURI;
+  public JSONArray visits;
+  public long      fennecDateVisited;
+  public long      fennecVisitCount;
+
+  @SuppressWarnings("unchecked")
+  private JSONArray copyVisits() {
+    if (this.visits == null) {
+      return null;
+    }
+    JSONArray out = new JSONArray();
+    out.addAll(this.visits);
+    return out;
+  }
+
+  @Override
+  public Record copyWithIDs(String guid, long androidID) {
+    HistoryRecord out = new HistoryRecord(guid, this.collection, this.lastModified, this.deleted);
+    out.androidID = androidID;
+    out.sortIndex = this.sortIndex;
+    out.ttl       = this.ttl;
+
+    // Copy HistoryRecord fields.
+    out.title             = this.title;
+    out.histURI           = this.histURI;
+    out.fennecDateVisited = this.fennecDateVisited;
+    out.fennecVisitCount  = this.fennecVisitCount;
+    out.visits            = this.copyVisits();
+
+    return out;
+  }
+
+  @Override
+  protected void populatePayload(ExtendedJSONObject payload) {
+    putPayload(payload, "id",      this.guid);
+    putPayload(payload, "title",   this.title);
+    putPayload(payload, "histUri", this.histURI);             // TODO: encoding?
+    payload.put("visits",  this.visits);
+  }
+
+  @Override
+  protected void initFromPayload(ExtendedJSONObject payload) {
+    this.histURI = (String) payload.get("histUri");
+    this.title   = (String) payload.get("title");
+    try {
+      this.visits = payload.getArray("visits");
+    } catch (NonArrayJSONException e) {
+      Logger.error(LOG_TAG, "Got non-array visits in history record " + this.guid, e);
+      this.visits = new JSONArray();
+    }
+  }
+
+  /**
+   * We consider two history records to be congruent if they represent the
+   * same history record regardless of visits. Titles are allowed to differ,
+   * but the URI must be the same.
+   */
+  @Override
+  public boolean congruentWith(Object o) {
+    if (!(o instanceof HistoryRecord)) {
+      return false;
+    }
+    HistoryRecord other = (HistoryRecord) o;
+    if (!super.congruentWith(other)) {
+      return false;
+    }
+    return RepoUtils.stringsEqual(this.histURI, other.histURI);
+  }
+
+  @Override
+  public boolean equalPayloads(Object o) {
+    if (!(o instanceof HistoryRecord)) {
+      Logger.debug(LOG_TAG, "Not a HistoryRecord: " + o.getClass());
+      return false;
+    }
+    HistoryRecord other = (HistoryRecord) o;
+    if (!super.equalPayloads(other)) {
+      Logger.debug(LOG_TAG, "super.equalPayloads returned false.");
+      return false;
+    }
+    return RepoUtils.stringsEqual(this.title, other.title) &&
+           RepoUtils.stringsEqual(this.histURI, other.histURI) &&
+           checkVisitsEquals(other);
+  }
+
+  @Override
+  public boolean equalAndroidIDs(Record other) {
+    return super.equalAndroidIDs(other) &&
+           this.equalFennecVisits(other);
+  }
+
+  private boolean equalFennecVisits(Record other) {
+    if (!(other instanceof HistoryRecord)) {
+      return false;
+    }
+    HistoryRecord h = (HistoryRecord) other;
+    return this.fennecDateVisited == h.fennecDateVisited &&
+           this.fennecVisitCount  == h.fennecVisitCount;
+  }
+
+  private boolean checkVisitsEquals(HistoryRecord other) {
+    Logger.debug(LOG_TAG, "Checking visits.");
+    if (Logger.LOG_PERSONAL_INFORMATION) {
+      // Don't JSON-encode unless we're logging.
+      Logger.pii(LOG_TAG, ">> Mine:   " + ((this.visits == null) ? "null" : this.visits.toJSONString()));
+      Logger.pii(LOG_TAG, ">> Theirs: " + ((other.visits == null) ? "null" : other.visits.toJSONString()));
+    }
+
+    // Handle nulls.
+    if (this.visits == other.visits) {
+      return true;
+    }
+
+    // Now they can't both be null.
+    int aSize = this.visits == null ? 0 : this.visits.size();
+    int bSize = other.visits == null ? 0 : other.visits.size();
+    
+    if (aSize != bSize) {
+      return false;
+    }
+
+    // Now neither of them can be null.
+
+    // TODO: do this by maintaining visits as a sorted array.
+    HashMap<Long, Long> otherVisits = new HashMap<Long, Long>();
+    for (int i = 0; i < bSize; i++) {
+      JSONObject visit = (JSONObject) other.visits.get(i);
+      otherVisits.put((Long) visit.get("date"), (Long) visit.get("type"));
+    }
+    
+    for (int i = 0; i < aSize; i++) {
+      JSONObject visit = (JSONObject) this.visits.get(i);
+      if (!otherVisits.containsKey(visit.get("date"))) {
+        return false;
+      }
+      Long otherDate = (Long) visit.get("date");
+      Long otherType = otherVisits.get(otherDate);
+      if (otherType == null) {
+        return false;
+      }
+      if (!otherType.equals((Long) visit.get("type"))) {
+        return false;
+      }
+    }
+    
+    return true;
+  }
+  
+//  
+//  Example record (note microsecond resolution):
+//
+//  {id:"--DUvUomABNq",
+//   histUri:"https://bugzilla.mozilla.org/show_bug.cgi?id=697634",
+//   title:"697634 \u2013 xpcshell test failures on 10.7",
+//   visits:[{date:1320087601465600, type:2},
+//           {date:1320084970724990, type:1},
+//           {date:1320084847035717, type:1},
+//           {date:1319764134412287, type:1},
+//           {date:1319757917982518, type:1},
+//           {date:1319751664627351, type:1},
+//           {date:1319681421072326, type:1},
+//           {date:1319681306455594, type:1},
+//           {date:1319678117125234, type:1},
+//           {date:1319677508862901, type:1}]
+//  }
+//   
+//"type" is a transition type:
+//
+//https://developer.mozilla.org/en/XPCOM_Interface_Reference/nsINavHistoryService#Transition_type_constants
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/HistoryRecordFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/HistoryRecordFactory.java
new file mode 100644
index 000000000..ac2c6a1dc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/HistoryRecordFactory.java
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+
+/**
+ * Turns CryptoRecords into HistoryRecords.
+ *
+ * @author rnewman
+ *
+ */
+public class HistoryRecordFactory extends RecordFactory {
+
+  @Override
+  public Record createRecord(Record record) {
+    HistoryRecord r = new HistoryRecord();
+    r.initFromEnvelope((CryptoRecord) record);
+    return r;
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/PasswordRecord.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/PasswordRecord.java
new file mode 100644
index 000000000..b2de60f3c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/PasswordRecord.java
@@ -0,0 +1,205 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.repositories.android.RepoUtils;
+
+public class PasswordRecord extends Record {
+  private static final String LOG_TAG = "PasswordRecord";
+
+  public static final String COLLECTION_NAME = "passwords";
+  public static long PASSWORDS_TTL = -1; // Never expire passwords.
+
+  // Payload strings.
+  public static final String PAYLOAD_HOSTNAME = "hostname";
+  public static final String PAYLOAD_FORM_SUBMIT_URL = "formSubmitURL";
+  public static final String PAYLOAD_HTTP_REALM = "httpRealm";
+  public static final String PAYLOAD_USERNAME = "username";
+  public static final String PAYLOAD_PASSWORD = "password";
+  public static final String PAYLOAD_USERNAME_FIELD = "usernameField";
+  public static final String PAYLOAD_PASSWORD_FIELD = "passwordField";
+
+  public PasswordRecord(String guid, String collection, long lastModified, boolean deleted) {
+    super(guid, collection, lastModified, deleted);
+    this.ttl = PASSWORDS_TTL;
+  }
+  public PasswordRecord(String guid, String collection, long lastModified) {
+    this(guid, collection, lastModified, false);
+  }
+  public PasswordRecord(String guid, String collection) {
+    this(guid, collection, 0, false);
+  }
+  public PasswordRecord(String guid) {
+    this(guid, COLLECTION_NAME, 0, false);
+  }
+  public PasswordRecord() {
+    this(Utils.generateGuid(), COLLECTION_NAME, 0, false);
+  }
+
+  public String id;
+  public String hostname;
+  public String formSubmitURL;
+  public String httpRealm;
+  // TODO these are encrypted in the passwords content provider,
+  // need to figure out what we need to do here.
+  public String usernameField;
+  public String passwordField;
+  public String encryptedUsername;
+  public String encryptedPassword;
+  public String encType;
+
+  public long   timeCreated;
+  public long   timeLastUsed;
+  public long   timePasswordChanged;
+  public long   timesUsed;
+
+
+  @Override
+  public Record copyWithIDs(String guid, long androidID) {
+    PasswordRecord out = new PasswordRecord(guid, this.collection, this.lastModified, this.deleted);
+    out.androidID = androidID;
+    out.sortIndex = this.sortIndex;
+    out.ttl       = this.ttl;
+
+    // Copy PasswordRecord fields.
+    out.id            = this.id;
+    out.hostname      = this.hostname;
+    out.formSubmitURL = this.formSubmitURL;
+    out.httpRealm     = this.httpRealm;
+
+    out.usernameField       = this.usernameField;
+    out.passwordField       = this.passwordField;
+    out.encryptedUsername   = this.encryptedUsername;
+    out.encryptedPassword   = this.encryptedPassword;
+    out.encType             = this.encType;
+
+    out.timeCreated         = this.timeCreated;
+    out.timeLastUsed        = this.timeLastUsed;
+    out.timePasswordChanged = this.timePasswordChanged;
+    out.timesUsed           = this.timesUsed;
+
+    return out;
+  }
+
+  @Override
+  public void initFromPayload(ExtendedJSONObject payload) {
+    this.hostname = payload.getString(PAYLOAD_HOSTNAME);
+    this.formSubmitURL = payload.getString(PAYLOAD_FORM_SUBMIT_URL);
+    this.httpRealm = payload.getString(PAYLOAD_HTTP_REALM);
+    this.encryptedUsername = payload.getString(PAYLOAD_USERNAME);
+    this.encryptedPassword = payload.getString(PAYLOAD_PASSWORD);
+    this.usernameField = payload.getString(PAYLOAD_USERNAME_FIELD);
+    this.passwordField = payload.getString(PAYLOAD_PASSWORD_FIELD);
+  }
+
+  @Override
+  public void populatePayload(ExtendedJSONObject payload) {
+    putPayload(payload, PAYLOAD_HOSTNAME, this.hostname);
+    putPayload(payload, PAYLOAD_FORM_SUBMIT_URL, this.formSubmitURL);
+    putPayload(payload, PAYLOAD_HTTP_REALM, this.httpRealm);
+    putPayload(payload, PAYLOAD_USERNAME, this.encryptedUsername);
+    putPayload(payload, PAYLOAD_PASSWORD, this.encryptedPassword);
+    putPayload(payload, PAYLOAD_USERNAME_FIELD, this.usernameField);
+    putPayload(payload, PAYLOAD_PASSWORD_FIELD, this.passwordField);
+  }
+
+  @Override
+  public boolean congruentWith(Object o) {
+    if (!(o instanceof PasswordRecord)) {
+      return false;
+    }
+    PasswordRecord other = (PasswordRecord) o;
+    if (!super.congruentWith(other)) {
+      return false;
+    }
+    return RepoUtils.stringsEqual(this.hostname, other.hostname)
+        && RepoUtils.stringsEqual(this.formSubmitURL, other.formSubmitURL)
+        // Bug 738347 - SQLiteBridge does not check for nulls in ContentValues.
+        // && RepoUtils.stringsEqual(this.httpRealm, other.httpRealm)
+        // && RepoUtils.stringsEqual(this.encType, other.encType)
+        && RepoUtils.stringsEqual(this.usernameField, other.usernameField)
+        && RepoUtils.stringsEqual(this.passwordField, other.passwordField)
+        && RepoUtils.stringsEqual(this.encryptedUsername, other.encryptedUsername)
+        && RepoUtils.stringsEqual(this.encryptedPassword, other.encryptedPassword);
+  }
+
+  @Override
+  public boolean equalPayloads(Object o) {
+    if (!(o instanceof PasswordRecord)) {
+      return false;
+    }
+
+    PasswordRecord other = (PasswordRecord) o;
+    Logger.debug("PasswordRecord", "thisRecord:" + this.toString());
+    Logger.debug("PasswordRecord", "otherRecord:" + o.toString());
+
+    if (this.deleted) {
+      if (other.deleted) {
+        // Deleted records are equal if their guids match.
+        return RepoUtils.stringsEqual(this.guid, other.guid);
+      }
+      // One record is deleted, the other is not. Not equal.
+      return false;
+    }
+
+    if (!super.equalPayloads(other)) {
+      Logger.debug(LOG_TAG, "super.equalPayloads returned false.");
+      return false;
+    }
+
+    return RepoUtils.stringsEqual(this.hostname, other.hostname)
+        && RepoUtils.stringsEqual(this.formSubmitURL, other.formSubmitURL)
+        // Bug 738347 - SQLiteBridge does not check for nulls in ContentValues.
+        // && RepoUtils.stringsEqual(this.httpRealm, other.httpRealm)
+        // && RepoUtils.stringsEqual(this.encType, other.encType)
+        && RepoUtils.stringsEqual(this.usernameField, other.usernameField)
+        && RepoUtils.stringsEqual(this.passwordField, other.passwordField)
+        && RepoUtils.stringsEqual(this.encryptedUsername, other.encryptedUsername)
+        && RepoUtils.stringsEqual(this.encryptedPassword, other.encryptedPassword);
+        // Desktop sync never sets timeCreated so this isn't relevant for sync records.
+  }
+
+  @Override
+  public String toString() {
+    return "PasswordRecord {"
+        + "lastModified: " + this.lastModified + ", "
+        + "hostname null?: " + (this.hostname == null) + ", "
+        + "formSubmitURL null?: " + (this.formSubmitURL == null) + ", "
+        + "httpRealm null?: " + (this.httpRealm == null) + ", "
+        + "usernameField null?: " + (this.usernameField == null) + ", "
+        + "passwordField null?: " + (this.passwordField == null) + ", "
+        + "encryptedUsername null?: " + (this.encryptedUsername == null) + ", "
+        + "encryptedPassword null?: " + (this.encryptedPassword == null) + ", "
+        + "encType: " + this.encType + ", "
+        + "timeCreated: " + this.timeCreated + ", "
+        + "timeLastUsed: " + this.timeLastUsed + ", "
+        + "timePasswordChanged: " + this.timePasswordChanged + ", "
+        + "timesUsed: " + this.timesUsed;
+  }
+
+  /**
+   * A PasswordRecord is considered valid if it abides by the database
+   * constraints of the PasswordsProvider (moz_logins).
+   *
+   * See toolkit/components/passwordmgr/storage-mozStorage.js for the
+   * definitions:
+   *
+   * http://hg.mozilla.org/mozilla-central/file/00955d61cc94/toolkit/components/passwordmgr/storage-mozStorage.js#l98
+   */
+    public boolean isValid() {
+        if (this.deleted) {
+            return true;
+        }
+
+        return this.hostname != null &&
+               this.encryptedUsername != null &&
+               this.encryptedPassword != null &&
+               this.usernameField != null &&
+               this.passwordField != null;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/PasswordRecordFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/PasswordRecordFactory.java
new file mode 100644
index 000000000..fc7ef916d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/PasswordRecordFactory.java
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+import org.mozilla.gecko.sync.repositories.domain.PasswordRecord;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+public class PasswordRecordFactory extends RecordFactory {
+  @Override
+  public Record createRecord(Record record) {
+    PasswordRecord r = new PasswordRecord();
+    r.initFromEnvelope((CryptoRecord) record);
+    return r;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/Record.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/Record.java
new file mode 100644
index 000000000..145704c1c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/Record.java
@@ -0,0 +1,308 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import java.io.UnsupportedEncodingException;
+
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+/**
+ * Record is the abstract base class for all entries that Sync processes:
+ * bookmarks, passwords, history, and such.
+ *
+ * A Record can be initialized from or serialized to a CryptoRecord for
+ * submission to an encrypted store.
+ *
+ * Records should be considered to be conventionally immutable: modifications
+ * should be completed before the new record object escapes its constructing
+ * scope. Note that this is a critically important part of equality. As Rich
+ * Hickey notes:
+ *
+ *   … the only things you can really compare for equality are immutable things,
+ *   because if you compare two things for equality that are mutable, and ever
+ *   say true, and they're ever not the same thing, you are wrong. Or you will
+ *   become wrong at some point in the future.
+ *
+ * Records have a layered definition of equality. Two records can be said to be
+ * "equal" if:
+ *
+ * * They have the same GUID and collection. Two crypto/keys records are in some
+ *   way "the same".
+ *   This is `equalIdentifiers`.
+ *
+ * * Their most significant fields are the same. That is to say, they share a
+ *   GUID, a collection, deletion, and domain-specific fields. Two copies of
+ *   crypto/keys, neither deleted, with the same encrypted data but different
+ *   modified times and sortIndex are in a stronger way "the same".
+ *   This is `equalPayloads`.
+ *
+ * * Their most significant fields are the same, and their local fields (e.g.,
+ *   the androidID to which we have decided that this record maps) are congruent.
+ *   A record with the same androidID, or one whose androidID has not been set,
+ *   can be considered "the same".
+ *   This concept can be extended by Record subclasses. The key point is that
+ *   reconciling should be applied to the contents of these records. For example,
+ *   two history records with the same URI and GUID, but different visit arrays,
+ *   can be said to be congruent.
+ *   This is `congruentWith`.
+ *
+ * * They are strictly identical. Every field that is persisted, including
+ *   lastModified and androidID, is equal.
+ *   This is `equals`.
+ *
+ * Different parts of the codebase have use for different layers of this
+ * comparison hierarchy. For instance, lastModified times change every time a
+ * record is stored; a store followed by a retrieval will return a Record that
+ * shares its most significant fields with the input, but has a later
+ * lastModified time and might not yet have values set for others. Reconciling
+ * will thus ignore the modification time of a record.
+ *
+ * @author rnewman
+ *
+ */
+public abstract class Record {
+
+  public String guid;
+  public String collection;
+  public long lastModified;
+  public boolean deleted;
+  public long androidID;
+  /**
+   * An integer indicating the relative importance of this item in the collection.
+   * <p>
+   * Default is 0.
+   */
+  public long sortIndex;
+  /**
+   * The number of seconds to keep this record. After that time this item will
+   * no longer be returned in response to any request, and it may be pruned from
+   * the database.
+   * <p>
+   * Negative values mean never forget this record.
+   * <p>
+   * Default is 1 year.
+   */
+  public long ttl;
+
+  public Record(String guid, String collection, long lastModified, boolean deleted) {
+    this.guid         = guid;
+    this.collection   = collection;
+    this.lastModified = lastModified;
+    this.deleted      = deleted;
+    this.sortIndex    = 0;
+    this.ttl          = 365 * 24 * 60 * 60; // Seconds.
+    this.androidID    = -1;
+  }
+
+  /**
+   * Return true iff the input is a Record and has the same
+   * collection and guid as this object.
+   */
+  public boolean equalIdentifiers(Object o) {
+    if (!(o instanceof Record)) {
+      return false;
+    }
+
+    Record other = (Record) o;
+    if (this.guid == null) {
+      if (other.guid != null) {
+        return false;
+      }
+    } else {
+      if (!this.guid.equals(other.guid)) {
+        return false;
+      }
+    }
+    if (this.collection == null) {
+      if (other.collection != null) {
+        return false;
+      }
+    } else {
+      if (!this.collection.equals(other.collection)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  /**
+   * @param o
+   *        The object to which this object should be compared.
+   * @return
+   *        true iff the input is a Record which is substantially the
+   *        same as this object.
+   */
+  public boolean equalPayloads(Object o) {
+    if (!this.equalIdentifiers(o)) {
+      return false;
+    }
+    Record other = (Record) o;
+    return this.deleted == other.deleted;
+  }
+
+  /**
+   *
+   *
+   * @param o
+   *        The object to which this object should be compared.
+   * @return
+   *        true iff the input is a Record which is substantially the
+   *        same as this object, considering the ability and desire to
+   *        reconcile the two objects if possible.
+   */
+  public boolean congruentWith(Object o) {
+    if (!this.equalIdentifiers(o)) {
+      return false;
+    }
+    Record other = (Record) o;
+    return congruentAndroidIDs(other) &&
+           (this.deleted == other.deleted);
+  }
+
+  public boolean congruentAndroidIDs(Record other) {
+    // We treat -1 as "unset", and treat this as
+    // congruent with any other value.
+    if (this.androidID  != -1 &&
+        other.androidID != -1 &&
+        this.androidID  != other.androidID) {
+      return false;
+    }
+    return true;
+  }
+
+  /**
+   * Return true iff the input is both equal in terms of payload,
+   * and also shares transient values such as timestamps.
+   */
+  @Override
+  public boolean equals(Object o) {
+    if (!(o instanceof Record)) {
+      return false;
+    }
+
+    Record other = (Record) o;
+    return equalTimestamps(other) &&
+           equalSortIndices(other) &&
+           equalAndroidIDs(other) &&
+           equalPayloads(o);
+  }
+
+  public boolean equalAndroidIDs(Record other) {
+    return this.androidID == other.androidID;
+  }
+
+  public boolean equalSortIndices(Record other) {
+    return this.sortIndex == other.sortIndex;
+  }
+
+  public boolean equalTimestamps(Object o) {
+    if (!(o instanceof Record)) {
+      return false;
+    }
+    return ((Record) o).lastModified == this.lastModified;
+  }
+
+  protected abstract void populatePayload(ExtendedJSONObject payload);
+  protected abstract void initFromPayload(ExtendedJSONObject payload);
+
+  public void initFromEnvelope(CryptoRecord envelope) {
+    ExtendedJSONObject p = envelope.payload;
+    this.guid = envelope.guid;
+    checkGUIDs(p);
+
+    this.collection    = envelope.collection;
+    this.lastModified  = envelope.lastModified;
+
+    final Object del = p.get("deleted");
+    if (del instanceof Boolean) {
+      this.deleted = (Boolean) del;
+    } else {
+      this.initFromPayload(p);
+    }
+
+  }
+
+  public CryptoRecord getEnvelope() {
+    CryptoRecord rec = new CryptoRecord(this);
+    ExtendedJSONObject payload = new ExtendedJSONObject();
+    payload.put("id", this.guid);
+
+    if (this.deleted) {
+      payload.put("deleted", true);
+    } else {
+      populatePayload(payload);
+    }
+    rec.payload = payload;
+    return rec;
+  }
+
+  @SuppressWarnings("static-method")
+  public String toJSONString() {
+    throw new RuntimeException("Cannot JSONify non-CryptoRecord Records.");
+  }
+
+  public byte[] toJSONBytes() {
+    try {
+      return this.toJSONString().getBytes("UTF-8");
+    } catch (UnsupportedEncodingException e) {
+      // Can't happen.
+      return null;
+    }
+  }
+
+  /**
+   * Utility for safely populating an output CryptoRecord.
+   *
+   * @param rec
+   * @param key
+   * @param value
+   */
+  @SuppressWarnings("static-method")
+  protected void putPayload(CryptoRecord rec, String key, String value) {
+    if (value == null) {
+      return;
+    }
+    rec.payload.put(key, value);
+  }
+
+  protected void putPayload(ExtendedJSONObject payload, String key, String value) {
+    this.putPayload(payload, key, value, false);
+  }
+
+  @SuppressWarnings("static-method")
+  protected void putPayload(ExtendedJSONObject payload, String key, String value, boolean excludeEmpty) {
+    if (value == null) {
+      return;
+    }
+    if (excludeEmpty && value.equals("")) {
+      return;
+    }
+    payload.put(key, value);
+  }
+
+  protected void checkGUIDs(ExtendedJSONObject payload) {
+    String payloadGUID = (String) payload.get("id");
+    if (this.guid == null ||
+        payloadGUID == null) {
+      String detailMessage = "Inconsistency: either envelope or payload GUID missing.";
+      throw new IllegalStateException(detailMessage);
+    }
+    if (!this.guid.equals(payloadGUID)) {
+      String detailMessage = "Inconsistency: record has envelope ID " + this.guid + ", payload ID " + payloadGUID;
+      throw new IllegalStateException(detailMessage);
+    }
+  }
+
+  /**
+   * Oh for persistent data structures.
+   *
+   * @param guid
+   * @param androidID
+   * @return
+   *        An identical copy of this record with the provided two values.
+   */
+  public abstract Record copyWithIDs(String guid, long androidID);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/RecordParseException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/RecordParseException.java
new file mode 100644
index 000000000..0d8fe90b2
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/RecordParseException.java
@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+
+public class RecordParseException extends Exception {
+  private static final long serialVersionUID = -5145494854722254491L;
+
+  public RecordParseException(String detailMessage) {
+    super(detailMessage);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/TabsRecord.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/TabsRecord.java
new file mode 100644
index 000000000..eb3a4f6d0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/TabsRecord.java
@@ -0,0 +1,153 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import java.util.ArrayList;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.db.Tab;
+import org.mozilla.gecko.db.BrowserContract;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonArrayJSONException;
+import org.mozilla.gecko.sync.Utils;
+
+import android.content.ContentValues;
+
+/**
+ * Represents a client's collection of tabs.
+ *
+ * @author rnewman
+ *
+ */
+public class TabsRecord extends Record {
+  public static final String LOG_TAG = "TabsRecord";
+
+  public static final String COLLECTION_NAME = "tabs";
+  public static final long TABS_TTL = 7 * 24 * 60 * 60; // 7 days in seconds.
+
+  public TabsRecord(String guid, String collection, long lastModified, boolean deleted) {
+    super(guid, collection, lastModified, deleted);
+    this.ttl = TABS_TTL;
+  }
+  public TabsRecord(String guid, String collection, long lastModified) {
+    this(guid, collection, lastModified, false);
+  }
+  public TabsRecord(String guid, String collection) {
+    this(guid, collection, 0, false);
+  }
+  public TabsRecord(String guid) {
+    this(guid, COLLECTION_NAME, 0, false);
+  }
+  public TabsRecord() {
+    this(Utils.generateGuid(), COLLECTION_NAME, 0, false);
+  }
+
+  public String clientName;
+  public ArrayList<Tab> tabs;
+
+  @Override
+  public void initFromPayload(ExtendedJSONObject payload) {
+    clientName = (String) payload.get("clientName");
+    try {
+      tabs = tabsFrom(payload.getArray("tabs"));
+    } catch (NonArrayJSONException e) {
+      // Oh well.
+      tabs = new ArrayList<Tab>();
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  protected static JSONArray tabsToJSON(ArrayList<Tab> tabs) {
+    JSONArray out = new JSONArray();
+    for (Tab tab : tabs) {
+      out.add(tabToJSONObject(tab));
+    }
+    return out;
+  }
+
+  protected static ArrayList<Tab> tabsFrom(JSONArray in) {
+    ArrayList<Tab> tabs = new ArrayList<Tab>(in.size());
+    for (Object o : in) {
+      if (o instanceof JSONObject) {
+        try {
+          tabs.add(TabsRecord.tabFromJSONObject((JSONObject) o));
+        } catch (NonArrayJSONException e) {
+          Logger.warn(LOG_TAG, "urlHistory is not an array for this tab.", e);
+        }
+      }
+    }
+    return tabs;
+  }
+
+  @Override
+  public void populatePayload(ExtendedJSONObject payload) {
+    putPayload(payload, "id", this.guid);
+    putPayload(payload, "clientName", this.clientName);
+    payload.put("tabs", tabsToJSON(this.tabs));
+  }
+
+  @Override
+  public Record copyWithIDs(String guid, long androidID) {
+    TabsRecord out = new TabsRecord(guid, this.collection, this.lastModified, this.deleted);
+    out.androidID = androidID;
+    out.sortIndex = this.sortIndex;
+    out.ttl       = this.ttl;
+
+    out.clientName = this.clientName;
+    out.tabs = new ArrayList<Tab>(this.tabs);
+
+    return out;
+  }
+
+  public ContentValues getClientsContentValues() {
+    ContentValues cv = new ContentValues();
+    cv.put(BrowserContract.Clients.GUID, this.guid);
+    cv.put(BrowserContract.Clients.NAME, this.clientName);
+    cv.put(BrowserContract.Clients.LAST_MODIFIED, this.lastModified);
+    return cv;
+  }
+
+  public ContentValues[] getTabsContentValues() {
+    int c = tabs.size();
+    ContentValues[] out = new ContentValues[c];
+    for (int i = 0; i < c; i++) {
+      out[i] = tabs.get(i).toContentValues(this.guid, i);
+    }
+    return out;
+  }
+
+  public static Tab tabFromJSONObject(JSONObject o) throws NonArrayJSONException {
+    ExtendedJSONObject obj = new ExtendedJSONObject(o);
+    String title      = obj.getString("title");
+    String icon       = obj.getString("icon");
+    JSONArray history = obj.getArray("urlHistory");
+
+    // Last used is inexplicably a string in seconds. Most of the time.
+    long lastUsed = 0;
+    Object lU = obj.get("lastUsed");
+    if (lU instanceof Number) {
+      lastUsed = ((Long) lU) * 1000L;
+    } else if (lU instanceof String) {
+      try {
+        lastUsed = Long.parseLong((String) lU, 10) * 1000L;
+      } catch (NumberFormatException e) {
+        Logger.debug(TabsRecord.LOG_TAG, "Invalid number format in lastUsed: " + lU);
+      }
+    }
+    return new Tab(title, icon, history, lastUsed);
+  }
+
+  @SuppressWarnings("unchecked")
+  public static JSONObject tabToJSONObject(Tab tab) {
+    JSONObject o = new JSONObject();
+    o.put("title", tab.title);
+    o.put("icon", tab.icon);
+    o.put("urlHistory", tab.history);
+    o.put("lastUsed", tab.lastUsed / 1000);
+    return o;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/TabsRecordFactory.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/TabsRecordFactory.java
new file mode 100644
index 000000000..9504434d8
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/TabsRecordFactory.java
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+
+public class TabsRecordFactory extends RecordFactory {
+  @Override
+  public Record createRecord(Record record) {
+    TabsRecord r = new TabsRecord();
+    r.initFromEnvelope((CryptoRecord) record);
+    return r;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/VersionConstants.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/VersionConstants.java
new file mode 100644
index 000000000..2d3d4fd32
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/domain/VersionConstants.java
@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.domain;
+
+public class VersionConstants {
+  public static final int BOOKMARKS_ENGINE_VERSION = 2;
+  public static final int CLIENTS_ENGINE_VERSION = 1;
+  public static final int FORMS_ENGINE_VERSION = 1;
+  public static final int HISTORY_ENGINE_VERSION = 1;
+  public static final int PASSWORDS_ENGINE_VERSION = 1;
+  public static final int TABS_ENGINE_VERSION = 1;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloader.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloader.java
new file mode 100644
index 000000000..5c3037e4d
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloader.java
@@ -0,0 +1,310 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.downloaders;
+
+import android.support.annotation.Nullable;
+import android.support.annotation.VisibleForTesting;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.DelayedWorkTracker;
+import org.mozilla.gecko.sync.net.SyncResponse;
+import org.mozilla.gecko.sync.net.SyncStorageCollectionRequest;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+import org.mozilla.gecko.sync.repositories.Server11Repository;
+import org.mozilla.gecko.sync.repositories.Server11RepositorySession;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URLEncoder;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Batching Downloader, which implements batching protocol as supported by Sync 1.5.
+ *
+ * Downloader's batching behaviour is configured via two parameters, obtained from the repository:
+ * - Per-batch limit, which specified how many records may be fetched in an individual GET request.
+ * - Total limit, which controls number of batch GET requests we will make.
+ *
+ *
+ * Batching is implemented via specifying a 'limit' GET parameter, and looking for an 'offset' token
+ * in the response. If offset token is present, this indicates that there are more records than what
+ * we've received so far, and we perform an additional fetch. Batching stops when either we hit a total
+ * limit, or offset token is no longer present (indicating that we're done).
+ *
+ * For unlimited repositories (such as passwords), both of these value will be -1. Downloader will not
+ * specify a limit parameter in this case, and the response will contain every record available and no
+ * offset token, thus fully completing in one go.
+ *
+ * In between batches, we maintain a Last-Modified timestamp, based off the value return in the header
+ * of the first response. Every response will have a Last-Modified header, indicating when the collection
+ * was modified last. We pass along this header in our subsequent requests in a X-If-Unmodified-Since
+ * header. Server will ensure that our collection did not change while we are batching, if it did it will
+ * fail our fetch with a 412 (Consequent Modification) error. Additionally, we perform the same checks
+ * locally.
+ */
+public class BatchingDownloader {
+    public static final String LOG_TAG = "BatchingDownloader";
+
+    protected final Server11Repository repository;
+    private final Server11RepositorySession repositorySession;
+    private final DelayedWorkTracker workTracker = new DelayedWorkTracker();
+    // Used to track outstanding requests, so that we can abort them as needed.
+    @VisibleForTesting
+    protected final Set<SyncStorageCollectionRequest> pending = Collections.synchronizedSet(new HashSet<SyncStorageCollectionRequest>());
+    /* @GuardedBy("this") */ private String lastModified;
+    /* @GuardedBy("this") */ private long numRecords = 0;
+
+    public BatchingDownloader(final Server11Repository repository, final Server11RepositorySession repositorySession) {
+        this.repository = repository;
+        this.repositorySession = repositorySession;
+    }
+
+    @VisibleForTesting
+    protected static String flattenIDs(String[] guids) {
+        // Consider using Utils.toDelimitedString if and when the signature changes
+        // to Collection<String> guids.
+        if (guids.length == 0) {
+            return "";
+        }
+        if (guids.length == 1) {
+            return guids[0];
+        }
+        // Assuming 12-char GUIDs. There should be a -1 in there, but we accumulate one comma too many.
+        StringBuilder b = new StringBuilder(guids.length * 12 + guids.length);
+        for (String guid : guids) {
+            b.append(guid);
+            b.append(",");
+        }
+        return b.substring(0, b.length() - 1);
+    }
+
+    @VisibleForTesting
+    protected void fetchWithParameters(long newer,
+                                    long batchLimit,
+                                    boolean full,
+                                    String sort,
+                                    String ids,
+                                    SyncStorageCollectionRequest request,
+                                    RepositorySessionFetchRecordsDelegate fetchRecordsDelegate)
+            throws URISyntaxException, UnsupportedEncodingException {
+        if (batchLimit > repository.getDefaultTotalLimit()) {
+            throw new IllegalArgumentException("Batch limit should not be greater than total limit");
+        }
+
+        request.delegate = new BatchingDownloaderDelegate(this, fetchRecordsDelegate, request,
+                newer, batchLimit, full, sort, ids);
+        this.pending.add(request);
+        request.get();
+    }
+
+    @VisibleForTesting
+    @Nullable
+    protected String encodeParam(String param) throws UnsupportedEncodingException {
+        if (param != null) {
+            return URLEncoder.encode(param, "UTF-8");
+        }
+        return null;
+    }
+
+    @VisibleForTesting
+    protected SyncStorageCollectionRequest makeSyncStorageCollectionRequest(long newer,
+                                                  long batchLimit,
+                                                  boolean full,
+                                                  String sort,
+                                                  String ids,
+                                                  String offset)
+            throws URISyntaxException, UnsupportedEncodingException {
+        URI collectionURI = repository.collectionURI(full, newer, batchLimit, sort, ids, encodeParam(offset));
+        Logger.debug(LOG_TAG, collectionURI.toString());
+
+        return new SyncStorageCollectionRequest(collectionURI);
+    }
+
+    public void fetchSince(long timestamp, RepositorySessionFetchRecordsDelegate fetchRecordsDelegate) {
+        this.fetchSince(timestamp, null, fetchRecordsDelegate);
+    }
+
+    private void fetchSince(long timestamp, String offset,
+                           RepositorySessionFetchRecordsDelegate fetchRecordsDelegate) {
+        long batchLimit = repository.getDefaultBatchLimit();
+        String sort = repository.getDefaultSort();
+
+        try {
+            SyncStorageCollectionRequest request = makeSyncStorageCollectionRequest(timestamp,
+                    batchLimit, true, sort, null, offset);
+            this.fetchWithParameters(timestamp, batchLimit, true, sort, null, request, fetchRecordsDelegate);
+        } catch (URISyntaxException | UnsupportedEncodingException e) {
+            fetchRecordsDelegate.onFetchFailed(e, null);
+        }
+    }
+
+    public void fetch(String[] guids, RepositorySessionFetchRecordsDelegate fetchRecordsDelegate) {
+        String ids = flattenIDs(guids);
+        String index = "index";
+
+        try {
+            SyncStorageCollectionRequest request = makeSyncStorageCollectionRequest(
+                    -1, -1, true, index, ids, null);
+            this.fetchWithParameters(-1, -1, true, index, ids, request, fetchRecordsDelegate);
+        } catch (URISyntaxException | UnsupportedEncodingException e) {
+            fetchRecordsDelegate.onFetchFailed(e, null);
+        }
+    }
+
+    public Server11Repository getServerRepository() {
+        return this.repository;
+    }
+
+    public void onFetchCompleted(SyncStorageResponse response,
+                                 final RepositorySessionFetchRecordsDelegate fetchRecordsDelegate,
+                                 final SyncStorageCollectionRequest request, long newer,
+                                 long limit, boolean full, String sort, String ids) {
+        removeRequestFromPending(request);
+
+        // When we process our first request, we get back a X-Last-Modified header indicating when collection was modified last.
+        // We pass it to the server with every subsequent request (if we need to make more) as the X-If-Unmodified-Since header,
+        // and server is supposed to ensure that this pre-condition is met, and fail our request with a 412 error code otherwise.
+        // So, if all of this happens, these checks should never fail.
+        // However, we also track this header in client side, and can defensively validate against it here as well.
+        final String currentLastModifiedTimestamp = response.lastModified();
+        Logger.debug(LOG_TAG, "Last modified timestamp " + currentLastModifiedTimestamp);
+
+        // Sanity check. We also did a null check in delegate before passing it into here.
+        if (currentLastModifiedTimestamp == null) {
+            this.abort(fetchRecordsDelegate, "Last modified timestamp is missing");
+            return;
+        }
+
+        final boolean lastModifiedChanged;
+        synchronized (this) {
+            if (this.lastModified == null) {
+                // First time seeing last modified timestamp.
+                this.lastModified = currentLastModifiedTimestamp;
+            }
+            lastModifiedChanged = !this.lastModified.equals(currentLastModifiedTimestamp);
+        }
+
+        if (lastModifiedChanged) {
+            this.abort(fetchRecordsDelegate, "Last modified timestamp has changed unexpectedly");
+            return;
+        }
+
+        final boolean hasNotReachedLimit;
+        synchronized (this) {
+            this.numRecords += response.weaveRecords();
+            hasNotReachedLimit = this.numRecords < repository.getDefaultTotalLimit();
+        }
+
+        final String offset = response.weaveOffset();
+        final SyncStorageCollectionRequest newRequest;
+        try {
+            newRequest = makeSyncStorageCollectionRequest(newer,
+                    limit, full, sort, ids, offset);
+        } catch (final URISyntaxException | UnsupportedEncodingException e) {
+            this.workTracker.delayWorkItem(new Runnable() {
+                @Override
+                public void run() {
+                    Logger.debug(LOG_TAG, "Delayed onFetchCompleted running.");
+                    fetchRecordsDelegate.onFetchFailed(e, null);
+                }
+            });
+            return;
+        }
+
+        if (offset != null && hasNotReachedLimit) {
+            try {
+                this.fetchWithParameters(newer, limit, full, sort, ids, newRequest, fetchRecordsDelegate);
+            } catch (final URISyntaxException | UnsupportedEncodingException e) {
+                this.workTracker.delayWorkItem(new Runnable() {
+                    @Override
+                    public void run() {
+                        Logger.debug(LOG_TAG, "Delayed onFetchCompleted running.");
+                        fetchRecordsDelegate.onFetchFailed(e, null);
+                    }
+                });
+            }
+            return;
+        }
+
+        final long normalizedTimestamp = response.normalizedTimestampForHeader(SyncResponse.X_LAST_MODIFIED);
+        Logger.debug(LOG_TAG, "Fetch completed. Timestamp is " + normalizedTimestamp);
+
+        this.workTracker.delayWorkItem(new Runnable() {
+            @Override
+            public void run() {
+                Logger.debug(LOG_TAG, "Delayed onFetchCompleted running.");
+                fetchRecordsDelegate.onFetchCompleted(normalizedTimestamp);
+            }
+        });
+    }
+
+    public void onFetchFailed(final Exception ex,
+                              final RepositorySessionFetchRecordsDelegate fetchRecordsDelegate,
+                              final SyncStorageCollectionRequest request) {
+        removeRequestFromPending(request);
+        this.workTracker.delayWorkItem(new Runnable() {
+            @Override
+            public void run() {
+                Logger.debug(LOG_TAG, "Running onFetchFailed.");
+                fetchRecordsDelegate.onFetchFailed(ex, null);
+            }
+        });
+    }
+
+    public void onFetchedRecord(CryptoRecord record,
+                                RepositorySessionFetchRecordsDelegate fetchRecordsDelegate) {
+        this.workTracker.incrementOutstanding();
+        try {
+            fetchRecordsDelegate.onFetchedRecord(record);
+        } catch (Exception ex) {
+            Logger.warn(LOG_TAG, "Got exception calling onFetchedRecord with WBO.", ex);
+            throw new RuntimeException(ex);
+        } finally {
+            this.workTracker.decrementOutstanding();
+        }
+    }
+
+    private void removeRequestFromPending(SyncStorageCollectionRequest request) {
+        if (request == null) {
+            return;
+        }
+        this.pending.remove(request);
+    }
+
+    @VisibleForTesting
+    protected void abortRequests() {
+        this.repositorySession.abort();
+        synchronized (this.pending) {
+            for (SyncStorageCollectionRequest request : this.pending) {
+                request.abort();
+            }
+            this.pending.clear();
+        }
+    }
+
+    @Nullable
+    protected synchronized String getLastModified() {
+        return this.lastModified;
+    }
+
+    private void abort(final RepositorySessionFetchRecordsDelegate delegate, final String msg) {
+        Logger.error(LOG_TAG, msg);
+        this.abortRequests();
+        this.workTracker.delayWorkItem(new Runnable() {
+            @Override
+            public void run() {
+                Logger.debug(LOG_TAG, "Delayed onFetchCompleted running.");
+                delegate.onFetchFailed(
+                        new IllegalStateException(msg),
+                        null);
+            }
+        });
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloaderDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloaderDelegate.java
new file mode 100644
index 000000000..eb9f76d6b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloaderDelegate.java
@@ -0,0 +1,91 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.downloaders;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.HTTPFailureException;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.SyncStorageCollectionRequest;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+import org.mozilla.gecko.sync.net.WBOCollectionRequestDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+
+/**
+ * Delegate that gets passed into fetch methods to handle server response from fetch.
+ */
+public class BatchingDownloaderDelegate extends WBOCollectionRequestDelegate {
+    public static final String LOG_TAG = "BatchingDownloaderDelegate";
+
+    private BatchingDownloader downloader;
+    private RepositorySessionFetchRecordsDelegate fetchRecordsDelegate;
+    public SyncStorageCollectionRequest request;
+    // Used to pass back to BatchDownloader to start another fetch with these parameters if needed.
+    private long newer;
+    private long batchLimit;
+    private boolean full;
+    private String sort;
+    private String ids;
+
+    public BatchingDownloaderDelegate(final BatchingDownloader downloader,
+                                      final RepositorySessionFetchRecordsDelegate fetchRecordsDelegate,
+                                      final SyncStorageCollectionRequest request, long newer,
+                                      long batchLimit, boolean full, String sort, String ids) {
+        this.downloader = downloader;
+        this.fetchRecordsDelegate = fetchRecordsDelegate;
+        this.request = request;
+        this.newer = newer;
+        this.batchLimit = batchLimit;
+        this.full = full;
+        this.sort = sort;
+        this.ids = ids;
+    }
+
+    @Override
+    public AuthHeaderProvider getAuthHeaderProvider() {
+        return this.downloader.getServerRepository().getAuthHeaderProvider();
+    }
+
+    @Override
+    public String ifUnmodifiedSince() {
+        return this.downloader.getLastModified();
+    }
+
+    @Override
+    public void handleRequestSuccess(SyncStorageResponse response) {
+        Logger.debug(LOG_TAG, "Fetch done.");
+        if (response.lastModified() != null) {
+            this.downloader.onFetchCompleted(response, this.fetchRecordsDelegate, this.request,
+                    this.newer, this.batchLimit, this.full, this.sort, this.ids);
+            return;
+        }
+        this.downloader.onFetchFailed(
+                new IllegalStateException("Missing last modified header from response"),
+                this.fetchRecordsDelegate,
+                this.request);
+    }
+
+    @Override
+    public void handleRequestFailure(SyncStorageResponse response) {
+        this.handleRequestError(new HTTPFailureException(response));
+    }
+
+    @Override
+    public void handleRequestError(final Exception ex) {
+        Logger.warn(LOG_TAG, "Got request error.", ex);
+        this.downloader.onFetchFailed(ex, this.fetchRecordsDelegate, this.request);
+    }
+
+    @Override
+    public void handleWBO(CryptoRecord record) {
+        this.downloader.onFetchedRecord(record, this.fetchRecordsDelegate);
+    }
+
+    @Override
+    public KeyBundle keyBundle() {
+        return null;
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BatchMeta.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BatchMeta.java
new file mode 100644
index 000000000..951588586
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BatchMeta.java
@@ -0,0 +1,165 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.uploaders;
+
+import android.support.annotation.CheckResult;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+
+import org.mozilla.gecko.background.common.log.Logger;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.mozilla.gecko.sync.repositories.uploaders.BatchingUploader.TokenModifiedException;
+import org.mozilla.gecko.sync.repositories.uploaders.BatchingUploader.LastModifiedChangedUnexpectedly;
+import org.mozilla.gecko.sync.repositories.uploaders.BatchingUploader.LastModifiedDidNotChange;
+
+/**
+ * Keeps track of token, Last-Modified value and GUIDs of succeeded records.
+ */
+/* @ThreadSafe */
+public class BatchMeta extends BufferSizeTracker {
+    private static final String LOG_TAG = "BatchMeta";
+
+    // Will be set once first payload upload succeeds. We don't expect this to change until we
+    // commit the batch, and which point it must change.
+    /* @GuardedBy("this") */ private Long lastModified;
+
+    // Will be set once first payload upload succeeds. We don't expect this to ever change until
+    // a commit succeeds, at which point this gets set to null.
+    /* @GuardedBy("this") */ private String token;
+
+    /* @GuardedBy("accessLock") */ private boolean isUnlimited = false;
+
+    // Accessed by synchronously running threads.
+    /* @GuardedBy("accessLock") */ private final List<String> successRecordGuids = new ArrayList<>();
+
+    /* @GuardedBy("accessLock") */ private boolean needsCommit = false;
+
+    protected final Long collectionLastModified;
+
+    public BatchMeta(@NonNull Object payloadLock, long maxBytes, long maxRecords, @Nullable Long collectionLastModified) {
+        super(payloadLock, maxBytes, maxRecords);
+        this.collectionLastModified = collectionLastModified;
+    }
+
+    protected void setIsUnlimited(boolean isUnlimited) {
+        synchronized (accessLock) {
+            this.isUnlimited = isUnlimited;
+        }
+    }
+
+    @Override
+    protected boolean canFit(long recordDeltaByteCount) {
+        synchronized (accessLock) {
+            return isUnlimited || super.canFit(recordDeltaByteCount);
+        }
+    }
+
+    @Override
+    @CheckResult
+    protected boolean addAndEstimateIfFull(long recordDeltaByteCount) {
+        synchronized (accessLock) {
+            needsCommit = true;
+            boolean isFull = super.addAndEstimateIfFull(recordDeltaByteCount);
+            return !isUnlimited && isFull;
+        }
+    }
+
+    protected boolean needToCommit() {
+        synchronized (accessLock) {
+            return needsCommit;
+        }
+    }
+
+    protected synchronized String getToken() {
+        return token;
+    }
+
+    protected synchronized void setToken(final String newToken, boolean isCommit) throws TokenModifiedException {
+        // Set token once in a batching mode.
+        // In a non-batching mode, this.token and newToken will be null, and this is a no-op.
+        if (token == null) {
+            token = newToken;
+            return;
+        }
+
+        // Sanity checks.
+        if (isCommit) {
+            // We expect token to be null when commit payload succeeds.
+            if (newToken != null) {
+                throw new TokenModifiedException();
+            } else {
+                token = null;
+            }
+            return;
+        }
+
+        // We expect new token to always equal current token for non-commit payloads.
+        if (!token.equals(newToken)) {
+            throw new TokenModifiedException();
+        }
+    }
+
+    protected synchronized Long getLastModified() {
+        if (lastModified == null) {
+            return collectionLastModified;
+        }
+        return lastModified;
+    }
+
+    protected synchronized void setLastModified(final Long newLastModified, final boolean expectedToChange) throws LastModifiedChangedUnexpectedly, LastModifiedDidNotChange {
+        if (lastModified == null) {
+            lastModified = newLastModified;
+            return;
+        }
+
+        if (!expectedToChange && !lastModified.equals(newLastModified)) {
+            Logger.debug(LOG_TAG, "Last-Modified timestamp changed when we didn't expect it");
+            throw new LastModifiedChangedUnexpectedly();
+
+        } else if (expectedToChange && lastModified.equals(newLastModified)) {
+            Logger.debug(LOG_TAG, "Last-Modified timestamp did not change when we expected it to");
+            throw new LastModifiedDidNotChange();
+
+        } else {
+            lastModified = newLastModified;
+        }
+    }
+
+    protected ArrayList<String> getSuccessRecordGuids() {
+        synchronized (accessLock) {
+            return new ArrayList<>(this.successRecordGuids);
+        }
+    }
+
+    protected void recordSucceeded(final String recordGuid) {
+        // Sanity check.
+        if (recordGuid == null) {
+            throw new IllegalStateException();
+        }
+
+        synchronized (accessLock) {
+            successRecordGuids.add(recordGuid);
+        }
+    }
+
+    @Override
+    protected boolean canFitRecordByteDelta(long byteDelta, long recordCount, long byteCount) {
+        return isUnlimited || super.canFitRecordByteDelta(byteDelta, recordCount, byteCount);
+    }
+
+    @Override
+    protected void reset() {
+        synchronized (accessLock) {
+            super.reset();
+            token = null;
+            lastModified = null;
+            successRecordGuids.clear();
+            needsCommit = false;
+        }
+    }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BatchingUploader.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BatchingUploader.java
new file mode 100644
index 000000000..26efbd136
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BatchingUploader.java
@@ -0,0 +1,344 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.uploaders;
+
+import android.net.Uri;
+import android.support.annotation.VisibleForTesting;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.InfoConfiguration;
+import org.mozilla.gecko.sync.Server11RecordPostFailedException;
+import org.mozilla.gecko.sync.net.SyncResponse;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+import org.mozilla.gecko.sync.repositories.Server11RepositorySession;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionStoreDelegate;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+import java.util.ArrayList;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Uploader which implements batching introduced in Sync 1.5.
+ *
+ * Batch vs payload terminology:
+ * - batch is comprised of a series of payloads, which are all committed at the same time.
+ * -- identified via a "batch token", which is returned after first payload for the batch has been uploaded.
+ * - payload is a collection of records which are uploaded together. Associated with a batch.
+ * -- last payload, identified via commit=true, commits the batch.
+ *
+ * Limits for how many records can fit into a payload and into a batch are defined in the passed-in
+ * InfoConfiguration object.
+ *
+ * If we can't fit everything we'd like to upload into one batch (according to max-total-* limits),
+ * then we commit that batch, and start a new one. There are no explicit limits on total number of
+ * batches we might use, although at some point we'll start to run into storage limit errors from the API.
+ *
+ * Once we go past using one batch this uploader is no longer "atomic". Partial state is exposed
+ * to other clients after our first batch is committed and before our last batch is committed.
+ * However, our per-batch limits are high, X-I-U-S mechanics help protect downloading clients
+ * (as long as they implement X-I-U-S) with 412 error codes in case of interleaving upload and download,
+ * and most mobile clients will not be uploading large-enough amounts of data (especially structured
+ * data, such as bookmarks).
+ *
+ * Last-Modified header returned with the first batch payload POST success is maintained for a batch,
+ * to guard against concurrent-modification errors (different uploader commits before we're done).
+ *
+ * Non-batching mode notes:
+ * We also support Sync servers which don't enable batching for uploads. In this case, we respect
+ * payload limits for individual uploads, and every upload is considered a commit. Batching limits
+ * do not apply, and batch token is irrelevant.
+ * We do keep track of Last-Modified and send along X-I-U-S with our uploads, to protect against
+ * concurrent modifications by other clients.
+ */
+public class BatchingUploader {
+    private static final String LOG_TAG = "BatchingUploader";
+
+    private final Uri collectionUri;
+
+    private volatile boolean recordUploadFailed = false;
+
+    private final BatchMeta batchMeta;
+    private final Payload payload;
+
+    // Accessed by synchronously running threads, OK to not synchronize and just make it volatile.
+    private volatile Boolean inBatchingMode;
+
+    // Used to ensure we have thread-safe access to the following:
+    // - byte and record counts in both Payload and BatchMeta objects
+    // - buffers in the Payload object
+    private final Object payloadLock = new Object();
+
+    protected Executor workQueue;
+    protected final RepositorySessionStoreDelegate sessionStoreDelegate;
+    protected final Server11RepositorySession repositorySession;
+
+    protected AtomicLong uploadTimestamp = new AtomicLong(0);
+
+    protected static final int PER_RECORD_OVERHEAD_BYTE_COUNT = RecordUploadRunnable.RECORD_SEPARATOR.length;
+    protected static final int PER_PAYLOAD_OVERHEAD_BYTE_COUNT = RecordUploadRunnable.RECORDS_END.length;
+
+    // Sanity check. RECORD_SEPARATOR and RECORD_START are assumed to be of the same length.
+    static {
+        if (RecordUploadRunnable.RECORD_SEPARATOR.length != RecordUploadRunnable.RECORDS_START.length) {
+            throw new IllegalStateException("Separator and start tokens must be of the same length");
+        }
+    }
+
+    public BatchingUploader(final Server11RepositorySession repositorySession, final Executor workQueue, final RepositorySessionStoreDelegate sessionStoreDelegate) {
+        this.repositorySession = repositorySession;
+        this.workQueue = workQueue;
+        this.sessionStoreDelegate = sessionStoreDelegate;
+        this.collectionUri = Uri.parse(repositorySession.getServerRepository().collectionURI().toString());
+
+        InfoConfiguration config = repositorySession.getServerRepository().getInfoConfiguration();
+        this.batchMeta = new BatchMeta(
+                payloadLock, config.maxTotalBytes, config.maxTotalRecords,
+                repositorySession.getServerRepository().getCollectionLastModified()
+        );
+        this.payload = new Payload(payloadLock, config.maxPostBytes, config.maxPostRecords);
+    }
+
+    public void process(final Record record) {
+        final String guid = record.guid;
+        final byte[] recordBytes = record.toJSONBytes();
+        final long recordDeltaByteCount = recordBytes.length + PER_RECORD_OVERHEAD_BYTE_COUNT;
+
+        Logger.debug(LOG_TAG, "Processing a record with guid: " + guid);
+
+        // We can't upload individual records which exceed our payload byte limit.
+        if ((recordDeltaByteCount + PER_PAYLOAD_OVERHEAD_BYTE_COUNT) > payload.maxBytes) {
+            sessionStoreDelegate.onRecordStoreFailed(new RecordTooLargeToUpload(), guid);
+            return;
+        }
+
+        synchronized (payloadLock) {
+            final boolean canFitRecordIntoBatch = batchMeta.canFit(recordDeltaByteCount);
+            final boolean canFitRecordIntoPayload = payload.canFit(recordDeltaByteCount);
+
+            // Record fits!
+            if (canFitRecordIntoBatch && canFitRecordIntoPayload) {
+                Logger.debug(LOG_TAG, "Record fits into the current batch and payload");
+                addAndFlushIfNecessary(recordDeltaByteCount, recordBytes, guid);
+
+            // Payload won't fit the record.
+            } else if (canFitRecordIntoBatch) {
+                Logger.debug(LOG_TAG, "Current payload won't fit incoming record, uploading payload.");
+                flush(false, false);
+
+                Logger.debug(LOG_TAG, "Recording the incoming record into a new payload");
+
+                // Keep track of the overflow record.
+                addAndFlushIfNecessary(recordDeltaByteCount, recordBytes, guid);
+
+            // Batch won't fit the record.
+            } else {
+                Logger.debug(LOG_TAG, "Current batch won't fit incoming record, committing batch.");
+                flush(true, false);
+
+                Logger.debug(LOG_TAG, "Recording the incoming record into a new batch");
+                batchMeta.reset();
+
+                // Keep track of the overflow record.
+                addAndFlushIfNecessary(recordDeltaByteCount, recordBytes, guid);
+            }
+        }
+    }
+
+    // Convenience function used from the process method; caller must hold a payloadLock.
+    private void addAndFlushIfNecessary(long byteCount, byte[] recordBytes, String guid) {
+        boolean isPayloadFull = payload.addAndEstimateIfFull(byteCount, recordBytes, guid);
+        boolean isBatchFull = batchMeta.addAndEstimateIfFull(byteCount);
+
+        // Preemptive commit batch or upload a payload if they're estimated to be full.
+        if (isBatchFull) {
+            flush(true, false);
+            batchMeta.reset();
+        } else if (isPayloadFull) {
+            flush(false, false);
+        }
+    }
+
+    public void noMoreRecordsToUpload() {
+        Logger.debug(LOG_TAG, "Received 'no more records to upload' signal.");
+
+        // Run this after the last payload succeeds, so that we know for sure if we're in a batching
+        // mode and need to commit with a potentially empty payload.
+        workQueue.execute(new Runnable() {
+            @Override
+            public void run() {
+                commitIfNecessaryAfterLastPayload();
+            }
+        });
+    }
+
+    @VisibleForTesting
+    protected void commitIfNecessaryAfterLastPayload() {
+        // Must be called after last payload upload finishes.
+        synchronized (payload) {
+            // If we have any pending records in the Payload, flush them!
+            if (!payload.isEmpty()) {
+                flush(true, true);
+
+            // If we have an empty payload but need to commit the batch in the batching mode, flush!
+            } else if (batchMeta.needToCommit() && Boolean.TRUE.equals(inBatchingMode)) {
+                flush(true, true);
+
+            // Otherwise, we're done.
+            } else {
+                finished(uploadTimestamp);
+            }
+        }
+    }
+
+    /**
+     * We've been told by our upload delegate that a payload succeeded.
+     * Depending on the type of payload and batch mode status, inform our delegate of progress.
+     *
+     * @param response success response to our commit post
+     * @param isCommit was this a commit upload?
+     * @param isLastPayload was this a very last payload we'll upload?
+     */
+    public void payloadSucceeded(final SyncStorageResponse response, final boolean isCommit, final boolean isLastPayload) {
+        // Sanity check.
+        if (inBatchingMode == null) {
+            throw new IllegalStateException("Can't process payload success until we know if we're in a batching mode");
+        }
+
+        // We consider records to have been committed if we're not in a batching mode or this was a commit.
+        // If records have been committed, notify our store delegate.
+        if (!inBatchingMode || isCommit) {
+            for (String guid : batchMeta.getSuccessRecordGuids()) {
+                sessionStoreDelegate.onRecordStoreSucceeded(guid);
+            }
+        }
+
+        // If this was our very last commit, we're done storing records.
+        // Get Last-Modified timestamp from the response, and pass it upstream.
+        if (isLastPayload) {
+            finished(response.normalizedTimestampForHeader(SyncResponse.X_LAST_MODIFIED));
+        }
+    }
+
+    public void lastPayloadFailed() {
+        finished(uploadTimestamp);
+    }
+
+    private void finished(long lastModifiedTimestamp) {
+        bumpTimestampTo(uploadTimestamp, lastModifiedTimestamp);
+        finished(uploadTimestamp);
+    }
+
+    private void finished(AtomicLong lastModifiedTimestamp) {
+        repositorySession.storeDone(lastModifiedTimestamp.get());
+    }
+
+    public BatchMeta getCurrentBatch() {
+        return batchMeta;
+    }
+
+    public void setInBatchingMode(boolean inBatchingMode) {
+        this.inBatchingMode = inBatchingMode;
+
+        // If we know for sure that we're not in a batching mode,
+        // consider our batch to be of unlimited size.
+        this.batchMeta.setIsUnlimited(!inBatchingMode);
+    }
+
+    public Boolean getInBatchingMode() {
+        return inBatchingMode;
+    }
+
+    public void setLastModified(final Long lastModified, final boolean isCommit) throws BatchingUploaderException {
+        // Sanity check.
+        if (inBatchingMode == null) {
+            throw new IllegalStateException("Can't process Last-Modified before we know we're in a batching mode.");
+        }
+
+        // In non-batching mode, every time we receive a Last-Modified timestamp, we expect it to change
+        // since records are "committed" (become visible to other clients) on every payload.
+        // In batching mode, we only expect Last-Modified to change when we commit a batch.
+        batchMeta.setLastModified(lastModified, isCommit || !inBatchingMode);
+    }
+
+    public void recordSucceeded(final String recordGuid) {
+        Logger.debug(LOG_TAG, "Record store succeeded: " + recordGuid);
+        batchMeta.recordSucceeded(recordGuid);
+    }
+
+    public void recordFailed(final String recordGuid) {
+        recordFailed(new Server11RecordPostFailedException(), recordGuid);
+    }
+
+    public void recordFailed(final Exception e, final String recordGuid) {
+        Logger.debug(LOG_TAG, "Record store failed for guid " + recordGuid + " with exception: " + e.toString());
+        recordUploadFailed = true;
+        sessionStoreDelegate.onRecordStoreFailed(e, recordGuid);
+    }
+
+    public Server11RepositorySession getRepositorySession() {
+        return repositorySession;
+    }
+
+    private static void bumpTimestampTo(final AtomicLong current, long newValue) {
+        while (true) {
+            long existing = current.get();
+            if (existing > newValue) {
+                return;
+            }
+            if (current.compareAndSet(existing, newValue)) {
+                return;
+            }
+        }
+    }
+
+    private void flush(final boolean isCommit, final boolean isLastPayload) {
+        final ArrayList<byte[]> outgoing;
+        final ArrayList<String> outgoingGuids;
+        final long byteCount;
+
+        // Even though payload object itself is thread-safe, we want to ensure we get these altogether
+        // as a "unit". Another approach would be to create a wrapper object for these values, but this works.
+        synchronized (payloadLock) {
+            outgoing = payload.getRecordsBuffer();
+            outgoingGuids = payload.getRecordGuidsBuffer();
+            byteCount = payload.getByteCount();
+        }
+
+        workQueue.execute(new RecordUploadRunnable(
+                new BatchingAtomicUploaderMayUploadProvider(),
+                collectionUri,
+                batchMeta,
+                new PayloadUploadDelegate(this, outgoingGuids, isCommit, isLastPayload),
+                outgoing,
+                byteCount,
+                isCommit
+        ));
+
+        payload.reset();
+    }
+
+    private class BatchingAtomicUploaderMayUploadProvider implements MayUploadProvider {
+        public boolean mayUpload() {
+            return !recordUploadFailed;
+        }
+    }
+
+    public static class BatchingUploaderException extends Exception {
+        private static final long serialVersionUID = 1L;
+    }
+    public static class RecordTooLargeToUpload extends BatchingUploaderException {
+        private static final long serialVersionUID = 1L;
+    }
+    public static class LastModifiedDidNotChange extends BatchingUploaderException {
+        private static final long serialVersionUID = 1L;
+    }
+    public static class LastModifiedChangedUnexpectedly extends BatchingUploaderException {
+        private static final long serialVersionUID = 1L;
+    }
+    public static class TokenModifiedException extends BatchingUploaderException {
+        private static final long serialVersionUID = 1L;
+    };
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BufferSizeTracker.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BufferSizeTracker.java
new file mode 100644
index 000000000..7f4c305f3
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BufferSizeTracker.java
@@ -0,0 +1,103 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.uploaders;
+
+import android.support.annotation.CallSuper;
+import android.support.annotation.CheckResult;
+
+/**
+ * Implements functionality shared by BatchMeta and Payload objects, namely:
+ * - keeping track of byte and record counts
+ * - incrementing those counts when records are added
+ * - checking if a record can fit
+ */
+/* @ThreadSafe */
+public abstract class BufferSizeTracker {
+    protected final Object accessLock;
+
+    /* @GuardedBy("accessLock") */ private long byteCount = BatchingUploader.PER_PAYLOAD_OVERHEAD_BYTE_COUNT;
+    /* @GuardedBy("accessLock") */ private long recordCount = 0;
+    /* @GuardedBy("accessLock") */ protected Long smallestRecordByteCount;
+
+    protected final long maxBytes;
+    protected final long maxRecords;
+
+    public BufferSizeTracker(Object accessLock, long maxBytes, long maxRecords) {
+        this.accessLock = accessLock;
+        this.maxBytes = maxBytes;
+        this.maxRecords = maxRecords;
+    }
+
+    @CallSuper
+    protected boolean canFit(long recordDeltaByteCount) {
+        synchronized (accessLock) {
+            return canFitRecordByteDelta(recordDeltaByteCount, recordCount, byteCount);
+        }
+    }
+
+    protected boolean isEmpty() {
+        synchronized (accessLock) {
+            return recordCount == 0;
+        }
+    }
+
+    /**
+     * Adds a record and returns a boolean indicating whether batch is estimated to be full afterwards.
+     */
+    @CheckResult
+    protected boolean addAndEstimateIfFull(long recordDeltaByteCount) {
+        synchronized (accessLock) {
+            // Sanity check. Calling this method when buffer won't fit the record is an error.
+            if (!canFitRecordByteDelta(recordDeltaByteCount, recordCount, byteCount)) {
+                throw new IllegalStateException("Buffer size exceeded");
+            }
+
+            byteCount += recordDeltaByteCount;
+            recordCount += 1;
+
+            if (smallestRecordByteCount == null || smallestRecordByteCount > recordDeltaByteCount) {
+                smallestRecordByteCount = recordDeltaByteCount;
+            }
+
+            // See if we're full or nearly full after adding a record.
+            // We're halving smallestRecordByteCount because we're erring
+            // on the side of "can hopefully fit". We're trying to upload as soon as we know we
+            // should, but we also need to be mindful of minimizing total number of uploads we make.
+            return !canFitRecordByteDelta(smallestRecordByteCount / 2, recordCount, byteCount);
+        }
+    }
+
+    protected long getByteCount() {
+        synchronized (accessLock) {
+            // Ensure we account for payload overhead twice when the batch is empty.
+            // Payload overhead is either RECORDS_START ("[") or RECORDS_END ("]"),
+            // and for an empty payload we need account for both ("[]").
+            if (recordCount == 0) {
+                return byteCount + BatchingUploader.PER_PAYLOAD_OVERHEAD_BYTE_COUNT;
+            }
+            return byteCount;
+        }
+    }
+
+    protected long getRecordCount() {
+        synchronized (accessLock) {
+            return recordCount;
+        }
+    }
+
+    @CallSuper
+    protected void reset() {
+        synchronized (accessLock) {
+            byteCount = BatchingUploader.PER_PAYLOAD_OVERHEAD_BYTE_COUNT;
+            recordCount = 0;
+        }
+    }
+
+    @CallSuper
+    protected boolean canFitRecordByteDelta(long byteDelta, long recordCount, long byteCount) {
+        return recordCount < maxRecords
+                && (byteCount + byteDelta) <= maxBytes;
+    }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/MayUploadProvider.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/MayUploadProvider.java
new file mode 100644
index 000000000..a1994cf62
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/MayUploadProvider.java
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.uploaders;
+
+public interface MayUploadProvider {
+    boolean mayUpload();
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/Payload.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/Payload.java
new file mode 100644
index 000000000..1ed9b5798
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/Payload.java
@@ -0,0 +1,66 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.uploaders;
+
+import android.support.annotation.CheckResult;
+
+import java.util.ArrayList;
+
+/**
+ * Owns per-payload record byte and recordGuid buffers.
+ */
+/* @ThreadSafe */
+public class Payload extends BufferSizeTracker {
+    // Data of outbound records.
+    /* @GuardedBy("accessLock") */ private final ArrayList<byte[]> recordsBuffer = new ArrayList<>();
+
+    // GUIDs of outbound records. Used to fail entire payloads.
+    /* @GuardedBy("accessLock") */ private final ArrayList<String> recordGuidsBuffer = new ArrayList<>();
+
+    public Payload(Object payloadLock, long maxBytes, long maxRecords) {
+        super(payloadLock, maxBytes, maxRecords);
+    }
+
+    @Override
+    protected boolean addAndEstimateIfFull(long recordDelta) {
+        throw new UnsupportedOperationException();
+    }
+
+    @CheckResult
+    protected boolean addAndEstimateIfFull(long recordDelta, byte[] recordBytes, String guid) {
+        synchronized (accessLock) {
+            recordsBuffer.add(recordBytes);
+            recordGuidsBuffer.add(guid);
+            return super.addAndEstimateIfFull(recordDelta);
+        }
+    }
+
+    @Override
+    protected void reset() {
+        synchronized (accessLock) {
+            super.reset();
+            recordsBuffer.clear();
+            recordGuidsBuffer.clear();
+        }
+    }
+
+    protected ArrayList<byte[]> getRecordsBuffer() {
+        synchronized (accessLock) {
+            return new ArrayList<>(recordsBuffer);
+        }
+    }
+
+    protected ArrayList<String> getRecordGuidsBuffer() {
+        synchronized (accessLock) {
+            return new ArrayList<>(recordGuidsBuffer);
+        }
+    }
+
+    protected boolean isEmpty() {
+        synchronized (accessLock) {
+            return recordsBuffer.isEmpty();
+        }
+    }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/PayloadUploadDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/PayloadUploadDelegate.java
new file mode 100644
index 000000000..e8bbb7df6
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/PayloadUploadDelegate.java
@@ -0,0 +1,185 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.uploaders;
+
+import org.json.simple.JSONArray;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.HTTPFailureException;
+import org.mozilla.gecko.sync.NonArrayJSONException;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.SyncResponse;
+import org.mozilla.gecko.sync.net.SyncStorageRequestDelegate;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+import java.util.ArrayList;
+
+public class PayloadUploadDelegate implements SyncStorageRequestDelegate {
+    private static final String LOG_TAG = "PayloadUploadDelegate";
+
+    private static final String KEY_BATCH = "batch";
+
+    private final BatchingUploader uploader;
+    private ArrayList<String> postedRecordGuids;
+    private final boolean isCommit;
+    private final boolean isLastPayload;
+
+    public PayloadUploadDelegate(BatchingUploader uploader, ArrayList<String> postedRecordGuids, boolean isCommit, boolean isLastPayload) {
+        this.uploader = uploader;
+        this.postedRecordGuids = postedRecordGuids;
+        this.isCommit = isCommit;
+        this.isLastPayload = isLastPayload;
+    }
+
+    @Override
+    public AuthHeaderProvider getAuthHeaderProvider() {
+        return uploader.getRepositorySession().getServerRepository().getAuthHeaderProvider();
+    }
+
+    @Override
+    public String ifUnmodifiedSince() {
+        final Long lastModified = uploader.getCurrentBatch().getLastModified();
+        if (lastModified == null) {
+            return null;
+        }
+        return Utils.millisecondsToDecimalSecondsString(lastModified);
+    }
+
+    @Override
+    public void handleRequestSuccess(final SyncStorageResponse response) {
+        // First, do some sanity checking.
+        if (response.getStatusCode() != 200 && response.getStatusCode() != 202) {
+            handleRequestError(
+                new IllegalStateException("handleRequestSuccess received a non-200/202 response: " + response.getStatusCode())
+            );
+            return;
+        }
+
+        // We always expect to see a Last-Modified header. It's returned with every success response.
+        if (!response.httpResponse().containsHeader(SyncResponse.X_LAST_MODIFIED)) {
+            handleRequestError(
+                    new IllegalStateException("Response did not have a Last-Modified header")
+            );
+            return;
+        }
+
+        // We expect to be able to parse the response as a JSON object.
+        final ExtendedJSONObject body;
+        try {
+            body = response.jsonObjectBody(); // jsonObjectBody() throws or returns non-null.
+        } catch (Exception e) {
+            Logger.error(LOG_TAG, "Got exception parsing POST success body.", e);
+            this.handleRequestError(e);
+            return;
+        }
+
+        // If we got a 200, it could be either a non-batching result, or a batch commit.
+        // - if we're in a batching mode, we expect this to be a commit.
+        // If we got a 202, we expect there to be a token present in the response
+        if (response.getStatusCode() == 200 && uploader.getCurrentBatch().getToken() != null) {
+            if (uploader.getInBatchingMode() && !isCommit) {
+                handleRequestError(
+                        new IllegalStateException("Got 200 OK in batching mode, but this was not a commit payload")
+                );
+                return;
+            }
+        } else if (response.getStatusCode() == 202) {
+            if (!body.containsKey(KEY_BATCH)) {
+                handleRequestError(
+                        new IllegalStateException("Batch response did not have a batch ID")
+                );
+                return;
+            }
+        }
+
+        // With sanity checks out of the way, can now safely say if we're in a batching mode or not.
+        // We only do this once per session.
+        if (uploader.getInBatchingMode() == null) {
+            uploader.setInBatchingMode(body.containsKey(KEY_BATCH));
+        }
+
+        // Tell current batch about the token we've received.
+        // Throws if token changed after being set once, or if we got a non-null token after a commit.
+        try {
+            uploader.getCurrentBatch().setToken(body.getString(KEY_BATCH), isCommit);
+        } catch (BatchingUploader.BatchingUploaderException e) {
+            handleRequestError(e);
+            return;
+        }
+
+        // Will throw if Last-Modified changed when it shouldn't have.
+        try {
+            uploader.setLastModified(
+                    response.normalizedTimestampForHeader(SyncResponse.X_LAST_MODIFIED),
+                    isCommit);
+        } catch (BatchingUploader.BatchingUploaderException e) {
+            handleRequestError(e);
+            return;
+        }
+
+        // All looks good up to this point, let's process success and failed arrays.
+        JSONArray success;
+        try {
+            success = body.getArray("success");
+        } catch (NonArrayJSONException e) {
+            handleRequestError(e);
+            return;
+        }
+
+        if (success != null && !success.isEmpty()) {
+            Logger.trace(LOG_TAG, "Successful records: " + success.toString());
+            for (Object o : success) {
+                try {
+                    uploader.recordSucceeded((String) o);
+                } catch (ClassCastException e) {
+                    Logger.error(LOG_TAG, "Got exception parsing POST success guid.", e);
+                    // Not much to be done.
+                }
+            }
+        }
+        // GC
+        success = null;
+
+        ExtendedJSONObject failed;
+        try {
+            failed = body.getObject("failed");
+        } catch (NonObjectJSONException e) {
+            handleRequestError(e);
+            return;
+        }
+
+        if (failed != null && !failed.object.isEmpty()) {
+            Logger.debug(LOG_TAG, "Failed records: " + failed.object.toString());
+            for (String guid : failed.keySet()) {
+                uploader.recordFailed(guid);
+            }
+        }
+        // GC
+        failed = null;
+
+        // And we're done! Let uploader finish up.
+        uploader.payloadSucceeded(response, isCommit, isLastPayload);
+    }
+
+    @Override
+    public void handleRequestFailure(final SyncStorageResponse response) {
+        this.handleRequestError(new HTTPFailureException(response));
+    }
+
+    @Override
+    public void handleRequestError(Exception e) {
+        for (String guid : postedRecordGuids) {
+            uploader.recordFailed(e, guid);
+        }
+        // GC
+        postedRecordGuids = null;
+
+        if (isLastPayload) {
+            uploader.lastPayloadFailed();
+        }
+    }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/RecordUploadRunnable.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/RecordUploadRunnable.java
new file mode 100644
index 000000000..ce2955102
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/RecordUploadRunnable.java
@@ -0,0 +1,176 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.repositories.uploaders;
+
+import android.net.Uri;
+import android.support.annotation.VisibleForTesting;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.Server11PreviousPostFailedException;
+import org.mozilla.gecko.sync.net.SyncStorageRequest;
+import org.mozilla.gecko.sync.net.SyncStorageRequestDelegate;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.ArrayList;
+
+import ch.boye.httpclientandroidlib.entity.ContentProducer;
+import ch.boye.httpclientandroidlib.entity.EntityTemplate;
+
+/**
+ * Responsible for creating and posting a <code>SyncStorageRequest</code> request object.
+ */
+public class RecordUploadRunnable implements Runnable {
+    public final String LOG_TAG = "RecordUploadRunnable";
+
+    public final static byte[] RECORDS_START = { 91 };      // [ in UTF-8
+    public final static byte[] RECORD_SEPARATOR = { 44 };   // , in UTF-8
+    public final static byte[] RECORDS_END = { 93 };        // ] in UTF-8
+
+    private static final String QUERY_PARAM_BATCH = "batch";
+    private static final String QUERY_PARAM_TRUE = "true";
+    private static final String QUERY_PARAM_BATCH_COMMIT = "commit";
+
+    private final MayUploadProvider mayUploadProvider;
+    private final SyncStorageRequestDelegate uploadDelegate;
+
+    private final ArrayList<byte[]> outgoing;
+    private final long byteCount;
+
+    // Used to construct POST URI during run().
+    @VisibleForTesting
+    public final boolean isCommit;
+    private final Uri collectionUri;
+    private final BatchMeta batchMeta;
+
+    public RecordUploadRunnable(MayUploadProvider mayUploadProvider,
+                                Uri collectionUri,
+                                BatchMeta batchMeta,
+                                SyncStorageRequestDelegate uploadDelegate,
+                                ArrayList<byte[]> outgoing,
+                                long byteCount,
+                                boolean isCommit) {
+        this.mayUploadProvider = mayUploadProvider;
+        this.uploadDelegate = uploadDelegate;
+        this.outgoing = outgoing;
+        this.byteCount = byteCount;
+        this.batchMeta = batchMeta;
+        this.collectionUri = collectionUri;
+        this.isCommit = isCommit;
+    }
+
+    public static class ByteArraysContentProducer implements ContentProducer {
+        ArrayList<byte[]> outgoing;
+        public ByteArraysContentProducer(ArrayList<byte[]> arrays) {
+            outgoing = arrays;
+        }
+
+        @Override
+        public void writeTo(OutputStream outstream) throws IOException {
+            int count = outgoing.size();
+            outstream.write(RECORDS_START);
+            if (count > 0) {
+                outstream.write(outgoing.get(0));
+                for (int i = 1; i < count; ++i) {
+                    outstream.write(RECORD_SEPARATOR);
+                    outstream.write(outgoing.get(i));
+                }
+            }
+            outstream.write(RECORDS_END);
+        }
+
+        public static long outgoingBytesCount(ArrayList<byte[]> outgoing) {
+            final long numberOfRecords = outgoing.size();
+
+            // Account for start and end tokens.
+            long count = RECORDS_START.length + RECORDS_END.length;
+
+            // Account for all the records.
+            for (int i = 0; i < numberOfRecords; i++) {
+                count += outgoing.get(i).length;
+            }
+
+            // Account for a separator between the records.
+            // There's one less separator than there are records.
+            if (numberOfRecords > 1) {
+                count += RECORD_SEPARATOR.length * (numberOfRecords - 1);
+            }
+
+            return count;
+        }
+    }
+
+    public static class ByteArraysEntity extends EntityTemplate {
+        private final long count;
+        public ByteArraysEntity(ArrayList<byte[]> arrays, long totalBytes) {
+            super(new ByteArraysContentProducer(arrays));
+            this.count = totalBytes;
+            this.setContentType("application/json");
+            // charset is set in BaseResource.
+
+            // Sanity check our byte counts.
+            long realByteCount = ByteArraysContentProducer.outgoingBytesCount(arrays);
+            if (realByteCount != totalBytes) {
+                throw new IllegalStateException("Mismatched byte counts. Received " + totalBytes + " while real byte count is " + realByteCount);
+            }
+        }
+
+        @Override
+        public long getContentLength() {
+            return count;
+        }
+
+        @Override
+        public boolean isRepeatable() {
+            return true;
+        }
+    }
+
+    @Override
+    public void run() {
+        if (!mayUploadProvider.mayUpload()) {
+            Logger.info(LOG_TAG, "Told not to proceed by the uploader. Cancelling upload, failing records.");
+            uploadDelegate.handleRequestError(new Server11PreviousPostFailedException());
+            return;
+        }
+
+        Logger.trace(LOG_TAG, "Running upload task. Outgoing records: " + outgoing.size());
+
+        // We don't want the task queue to proceed until this request completes.
+        // Fortunately, BaseResource is currently synchronous.
+        // If that ever changes, you'll need to block here.
+
+        final URI postURI = buildPostURI(isCommit, batchMeta, collectionUri);
+        final SyncStorageRequest request = new SyncStorageRequest(postURI);
+        request.delegate = uploadDelegate;
+
+        ByteArraysEntity body = new ByteArraysEntity(outgoing, byteCount);
+        request.post(body);
+    }
+
+    @VisibleForTesting
+    public static URI buildPostURI(boolean isCommit, BatchMeta batchMeta, Uri collectionUri) {
+        final Uri.Builder uriBuilder = collectionUri.buildUpon();
+        final String batchToken = batchMeta.getToken();
+
+        if (batchToken != null) {
+            uriBuilder.appendQueryParameter(QUERY_PARAM_BATCH, batchToken);
+        } else {
+            uriBuilder.appendQueryParameter(QUERY_PARAM_BATCH, QUERY_PARAM_TRUE);
+        }
+
+        if (isCommit) {
+            uriBuilder.appendQueryParameter(QUERY_PARAM_BATCH_COMMIT, QUERY_PARAM_TRUE);
+        }
+
+        try {
+            return new URI(uriBuilder.build().toString());
+        } catch (URISyntaxException e) {
+            throw new IllegalStateException("Failed to construct a collection URI", e);
+        }
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/Constants.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/Constants.java
new file mode 100644
index 000000000..66e6768b4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/Constants.java
@@ -0,0 +1,29 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.setup;
+
+public class Constants {
+  public static final String DEFAULT_PROFILE = "default";
+
+  /**
+   * Key in sync extras bundle specifying stages to sync this sync session.
+   * <p>
+   * Corresponding value should be a String JSON-encoding an object, the keys of
+   * which are the stage names to sync. For example:
+   * <code>"{ \"stageToSync\": 0 }"</code>.
+   */
+  public static final String EXTRAS_KEY_STAGES_TO_SYNC = "sync";
+
+  /**
+   * Key in sync extras bundle specifying stages to skip this sync session.
+   * <p>
+   * Corresponding value should be a String JSON-encoding an object, the keys of
+   * which are the stage names to skip. For example:
+   * <code>"{ \"stageToSkip\": 0 }"</code>.
+   */
+  public static final String EXTRAS_KEY_STAGES_TO_SKIP = "skip";
+
+  public static final String JSON_KEY_ACCOUNT    = "account";
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/InvalidSyncKeyException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/InvalidSyncKeyException.java
new file mode 100644
index 000000000..ac0fd58d0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/InvalidSyncKeyException.java
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.setup;
+
+public class InvalidSyncKeyException extends Exception {
+  private static final long serialVersionUID = -6504925951580479894L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/activities/ActivityUtils.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/activities/ActivityUtils.java
new file mode 100644
index 000000000..6542e1b00
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/activities/ActivityUtils.java
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.setup.activities;
+
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+
+import org.mozilla.gecko.background.common.GlobalConstants;
+import org.mozilla.gecko.db.BrowserContract;
+
+public class ActivityUtils {
+  /**
+   * Open a URL in Fennec, if one is provided; or just open Fennec.
+   *
+   * @param context Android context.
+   * @param url to visit, or null to just open Fennec.
+   */
+  public static void openURLInFennec(final Context context, final String url) {
+    Intent intent;
+    if (url != null) {
+      intent = new Intent(Intent.ACTION_VIEW);
+      intent.setData(Uri.parse(url));
+    } else {
+      intent = new Intent(Intent.ACTION_MAIN);
+    }
+    intent.setClassName(GlobalConstants.BROWSER_INTENT_PACKAGE, GlobalConstants.BROWSER_INTENT_CLASS);
+    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+    intent.putExtra(BrowserContract.SKIP_TAB_QUEUE_FLAG, true);
+    context.startActivity(intent);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/activities/WebURLFinder.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/activities/WebURLFinder.java
new file mode 100644
index 000000000..8411d2a62
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/setup/activities/WebURLFinder.java
@@ -0,0 +1,161 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.setup.activities;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class WebURLFinder {
+  /**
+   * These regular expressions are taken from Android's Patterns.java.
+   * We brought them in to standardize URL matching across Android versions, instead of relying
+   * on Android version-dependent built-ins that can vary across Android versions.
+   * The original code can be found here:
+   * http://androidxref.com/6.0.1_r10/xref/frameworks/base/core/java/android/util/Patterns.java
+   *
+   */
+  public static final String GOOD_IRI_CHAR = "a-zA-Z0-9\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF";
+  public static final String GOOD_GTLD_CHAR = "a-zA-Z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF";
+  public static final String IRI = "[" + GOOD_IRI_CHAR + "]([" + GOOD_IRI_CHAR + "\\-]{0,61}[" + GOOD_IRI_CHAR + "]){0,1}";
+  public static final String GTLD = "[" + GOOD_GTLD_CHAR + "]{2,63}";
+  public static final String HOST_NAME = "(" + IRI + "\\.)+" + GTLD;
+  public static final Pattern IP_ADDRESS = Pattern.compile("((25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9])\\.(25[0-5]|2[0-4]"
+          + "[0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1]"
+          + "[0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}"
+          + "|[1-9][0-9]|[0-9]))");
+  public static final Pattern DOMAIN_NAME = Pattern.compile("(" + HOST_NAME + "|" + IP_ADDRESS + ")");
+  public static final Pattern WEB_URL = Pattern.compile("((?:(http|https|Http|Https|rtsp|Rtsp):\\/\\/(?:(?:[a-zA-Z0-9\\$\\-\\_\\.\\+\\!\\*\\'\\(\\)"
+          + "\\,\\;\\?\\&\\=]|(?:\\%[a-fA-F0-9]{2})){1,64}(?:\\:(?:[a-zA-Z0-9\\$\\-\\_"
+          + "\\.\\+\\!\\*\\'\\(\\)\\,\\;\\?\\&\\=]|(?:\\%[a-fA-F0-9]{2})){1,25})?\\@)?)?"
+          + "(?:" + DOMAIN_NAME + ")"
+          + "(?:\\:\\d{1,5})?)"
+          + "(\\/(?:(?:[" + GOOD_IRI_CHAR + "\\;\\/\\?\\:\\@\\&\\=\\#\\~"
+          + "\\-\\.\\+\\!\\*\\'\\(\\)\\,\\_])|(?:\\%[a-fA-F0-9]{2}))*)?"
+          + "(?:\\b|$)");
+
+  public final List<String> candidates;
+
+  public WebURLFinder(String string) {
+    if (string == null) {
+      throw new IllegalArgumentException("string must not be null");
+    }
+
+    this.candidates = candidateWebURLs(string);
+  }
+
+  public WebURLFinder(List<String> strings) {
+    if (strings == null) {
+      throw new IllegalArgumentException("strings must not be null");
+    }
+
+    this.candidates = candidateWebURLs(strings);
+  }
+
+  /**
+   * Check if string is a Web URL.
+   * <p>
+   * A Web URL is a URI that is not a <code>file:</code> or
+   * <code>javascript:</code> scheme.
+   *
+   * @param string
+   *          to check.
+   * @return <code>true</code> if <code>string</code> is a Web URL.
+   */
+  public static boolean isWebURL(String string) {
+    try {
+      new URI(string);
+    } catch (Exception e) {
+      return false;
+    }
+
+    if (android.webkit.URLUtil.isFileUrl(string) ||
+        android.webkit.URLUtil.isJavaScriptUrl(string)) {
+      return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Return best Web URL.
+   * <p>
+   * "Best" means a Web URL with a scheme, and failing that, a Web URL without a
+   * scheme.
+   *
+   * @return a Web URL or <code>null</code>.
+   */
+  public String bestWebURL() {
+    String firstWebURLWithScheme = firstWebURLWithScheme();
+    if (firstWebURLWithScheme != null) {
+      return firstWebURLWithScheme;
+    }
+
+    return firstWebURLWithoutScheme();
+  }
+
+  protected static List<String> candidateWebURLs(Collection<String> strings) {
+    List<String> candidates = new ArrayList<String>();
+
+    for (String string : strings) {
+      if (string == null) {
+        continue;
+      }
+
+      candidates.addAll(candidateWebURLs(string));
+    }
+
+    return candidates;
+  }
+
+  protected static List<String> candidateWebURLs(String string) {
+    Matcher matcher = WEB_URL.matcher(string);
+    List<String> matches = new LinkedList<String>();
+
+    while (matcher.find()) {
+      // Remove URLs with bad schemes.
+      if (!isWebURL(matcher.group())) {
+        continue;
+      }
+
+      // Remove parts of email addresses.
+      if (matcher.start() > 0 && (string.charAt(matcher.start() - 1) == '@')) {
+        continue;
+      }
+
+      matches.add(matcher.group());
+    }
+
+    return matches;
+  }
+
+  protected String firstWebURLWithScheme() {
+    for (String match : candidates) {
+      try {
+        if (new URI(match).getScheme() != null) {
+          return match;
+        }
+      } catch (URISyntaxException e) {
+        // Ignore: on to the next.
+        continue;
+      }
+    }
+
+    return null;
+  }
+
+  protected String firstWebURLWithoutScheme() {
+    if (!candidates.isEmpty()) {
+      return candidates.get(0);
+    }
+
+    return null;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AbstractNonRepositorySyncStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AbstractNonRepositorySyncStage.java
new file mode 100644
index 000000000..c910216eb
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AbstractNonRepositorySyncStage.java
@@ -0,0 +1,26 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+
+/**
+ * This is simply a stage that is not responsible for synchronizing repositories.
+ */
+public abstract class AbstractNonRepositorySyncStage extends AbstractSessionManagingSyncStage {
+  @Override
+  protected void resetLocal() {
+    // Do nothing.
+  }
+
+  @Override
+  protected void wipeLocal() {
+    // Do nothing.
+  }
+
+  @Override
+  public Integer getStorageVersion() {
+    return null; // Never include these engines in any meta/global records.
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AbstractSessionManagingSyncStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AbstractSessionManagingSyncStage.java
new file mode 100644
index 000000000..6592c3baa
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AbstractSessionManagingSyncStage.java
@@ -0,0 +1,43 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import org.mozilla.gecko.sync.GlobalSession;
+
+/**
+ * A global sync stage that manages a <code>GlobalSession</code> instance. This
+ * class is intended to be temporary: it should disappear as work to make
+ * data-driven syncs progresses.
+ * <p>
+ * This class is inherently <b>thread-unsafe</b>: if <code>session</code> is
+ * mutated after being set, all sorts of bad things could occur. At the time of
+ * writing, every <code>GlobalSyncStage</code> created is executed (wiped,
+ * reset) with the same <code>GlobalSession</code> argument.
+ */
+public abstract class AbstractSessionManagingSyncStage implements GlobalSyncStage {
+  protected GlobalSession session;
+
+  protected abstract void execute() throws NoSuchStageException;
+  protected abstract void resetLocal();
+  protected abstract void wipeLocal() throws Exception;
+
+  @Override
+  public void resetLocal(GlobalSession session) {
+    this.session = session;
+    resetLocal();
+  }
+
+  @Override
+  public void wipeLocal(GlobalSession session) throws Exception {
+    this.session = session;
+    wipeLocal();
+  }
+
+  @Override
+  public void execute(GlobalSession session) throws NoSuchStageException {
+    this.session = session;
+    execute();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AndroidBrowserBookmarksServerSyncStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AndroidBrowserBookmarksServerSyncStage.java
new file mode 100644
index 000000000..10e209230
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AndroidBrowserBookmarksServerSyncStage.java
@@ -0,0 +1,80 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import java.net.URISyntaxException;
+
+import org.mozilla.gecko.sync.JSONRecordFetcher;
+import org.mozilla.gecko.sync.MetaGlobalException;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.android.AndroidBrowserBookmarksRepository;
+import org.mozilla.gecko.sync.repositories.domain.BookmarkRecordFactory;
+import org.mozilla.gecko.sync.repositories.domain.VersionConstants;
+
+public class AndroidBrowserBookmarksServerSyncStage extends ServerSyncStage {
+  protected static final String LOG_TAG = "BookmarksStage";
+
+  // Eventually this kind of sync stage will be data-driven,
+  // and all this hard-coding can go away.
+  private static final String BOOKMARKS_SORT          = "index";
+  // Sanity limit. Batch and total limit are the same for now, and will be adjusted
+  // once buffer and high water mark are in place. See Bug 730142.
+  private static final long BOOKMARKS_BATCH_LIMIT = 5000;
+  private static final long BOOKMARKS_TOTAL_LIMIT = 5000;
+
+  @Override
+  protected String getCollection() {
+    return "bookmarks";
+  }
+
+  @Override
+  protected String getEngineName() {
+    return "bookmarks";
+  }
+
+  @Override
+  public Integer getStorageVersion() {
+    return VersionConstants.BOOKMARKS_ENGINE_VERSION;
+  }
+
+  @Override
+  protected Repository getRemoteRepository() throws URISyntaxException {
+    // If this is a first sync, we need to check server counts to make sure that we aren't
+    // going to screw up. SafeConstrainedServer11Repository does this. See Bug 814331.
+    AuthHeaderProvider authHeaderProvider = session.getAuthHeaderProvider();
+    final JSONRecordFetcher countsFetcher = new JSONRecordFetcher(session.config.infoCollectionCountsURL(), authHeaderProvider);
+    String collection = getCollection();
+    return new SafeConstrainedServer11Repository(
+        collection,
+        session.config.storageURL(),
+        session.getAuthHeaderProvider(),
+        session.config.infoCollections,
+        session.config.infoConfiguration,
+        BOOKMARKS_BATCH_LIMIT,
+        BOOKMARKS_TOTAL_LIMIT,
+        BOOKMARKS_SORT,
+        countsFetcher);
+  }
+
+  @Override
+  protected Repository getLocalRepository() {
+    return new AndroidBrowserBookmarksRepository();
+  }
+
+  @Override
+  protected RecordFactory getRecordFactory() {
+    return new BookmarkRecordFactory();
+  }
+
+  @Override
+  protected boolean isEnabled() throws MetaGlobalException {
+    if (session == null || session.getContext() == null) {
+      return false;
+    }
+    return super.isEnabled();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AndroidBrowserHistoryServerSyncStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AndroidBrowserHistoryServerSyncStage.java
new file mode 100644
index 000000000..947a10898
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/AndroidBrowserHistoryServerSyncStage.java
@@ -0,0 +1,74 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import java.net.URISyntaxException;
+
+import org.mozilla.gecko.sync.MetaGlobalException;
+import org.mozilla.gecko.sync.repositories.ConstrainedServer11Repository;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.android.AndroidBrowserHistoryRepository;
+import org.mozilla.gecko.sync.repositories.domain.HistoryRecordFactory;
+import org.mozilla.gecko.sync.repositories.domain.VersionConstants;
+
+public class AndroidBrowserHistoryServerSyncStage extends ServerSyncStage {
+  protected static final String LOG_TAG = "HistoryStage";
+
+  // Eventually this kind of sync stage will be data-driven,
+  // and all this hard-coding can go away.
+  private static final String HISTORY_SORT          = "index";
+  // Sanity limit. Batch and total limit are the same for now, and will be adjusted
+  // once buffer and high water mark are in place. See Bug 730142.
+  private static final long HISTORY_BATCH_LIMIT = 250;
+  private static final long HISTORY_TOTAL_LIMIT = 250;
+
+  @Override
+  protected String getCollection() {
+    return "history";
+  }
+
+  @Override
+  protected String getEngineName() {
+    return "history";
+  }
+
+  @Override
+  public Integer getStorageVersion() {
+    return VersionConstants.HISTORY_ENGINE_VERSION;
+  }
+
+  @Override
+  protected Repository getLocalRepository() {
+    return new AndroidBrowserHistoryRepository();
+  }
+
+  @Override
+  protected Repository getRemoteRepository() throws URISyntaxException {
+    String collection = getCollection();
+    return new ConstrainedServer11Repository(
+                                             collection,
+                                             session.config.storageURL(),
+                                             session.getAuthHeaderProvider(),
+                                             session.config.infoCollections,
+                                             session.config.infoConfiguration,
+                                             HISTORY_BATCH_LIMIT,
+                                             HISTORY_TOTAL_LIMIT,
+                                             HISTORY_SORT);
+  }
+
+  @Override
+  protected RecordFactory getRecordFactory() {
+    return new HistoryRecordFactory();
+  }
+
+  @Override
+  protected boolean isEnabled() throws MetaGlobalException {
+    if (session == null || session.getContext() == null) {
+      return false;
+    }
+    return super.isEnabled();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/CheckPreconditionsStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/CheckPreconditionsStage.java
new file mode 100644
index 000000000..b33f83ad1
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/CheckPreconditionsStage.java
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+
+public class CheckPreconditionsStage extends AbstractNonRepositorySyncStage {
+  @Override
+  public void execute() throws NoSuchStageException {
+    session.advance();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/CompletedStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/CompletedStage.java
new file mode 100644
index 000000000..7ec776324
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/CompletedStage.java
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+
+
+public class CompletedStage extends AbstractNonRepositorySyncStage {
+  @Override
+  public void execute() throws NoSuchStageException {
+    // TODO: Update tracking timestamps, close connections, etc.
+    // TODO: call clean() on each Repository in the sync constellation.
+    session.completeSync();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/EnsureCrypto5KeysStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/EnsureCrypto5KeysStage.java
new file mode 100644
index 000000000..5031cf770
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/EnsureCrypto5KeysStage.java
@@ -0,0 +1,192 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import java.net.URISyntaxException;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.CollectionKeys;
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.InfoCollections;
+import org.mozilla.gecko.sync.NoCollectionKeysSetException;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.crypto.PersistedCrypto5Keys;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.SyncStorageRecordRequest;
+import org.mozilla.gecko.sync.net.SyncStorageRequestDelegate;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+public class EnsureCrypto5KeysStage
+extends AbstractNonRepositorySyncStage
+implements SyncStorageRequestDelegate {
+
+  private static final String LOG_TAG = "EnsureC5KeysStage";
+  private static final String CRYPTO_COLLECTION = "crypto";
+  protected boolean retrying = false;
+
+  @Override
+  public void execute() throws NoSuchStageException {
+    InfoCollections infoCollections = session.config.infoCollections;
+    if (infoCollections == null) {
+      session.abort(null, "No info/collections set in EnsureCrypto5KeysStage.");
+      return;
+    }
+
+    PersistedCrypto5Keys pck = session.config.persistedCryptoKeys();
+    long lastModified = pck.lastModified();
+    if (retrying || !infoCollections.updateNeeded(CRYPTO_COLLECTION, lastModified)) {
+      // Try to use our local collection keys for this session.
+      Logger.debug(LOG_TAG, "Trying to use persisted collection keys for this session.");
+      CollectionKeys keys = pck.keys();
+      if (keys != null) {
+        Logger.trace(LOG_TAG, "Using persisted collection keys for this session.");
+        session.config.setCollectionKeys(keys);
+        session.advance();
+        return;
+      }
+      Logger.trace(LOG_TAG, "Failed to use persisted collection keys for this session.");
+    }
+
+    // We need an update: fetch fresh keys.
+    Logger.debug(LOG_TAG, "Fetching fresh collection keys for this session.");
+    try {
+      SyncStorageRecordRequest request = new SyncStorageRecordRequest(session.wboURI(CRYPTO_COLLECTION, "keys"));
+      request.delegate = this;
+      request.get();
+    } catch (URISyntaxException e) {
+      session.abort(e, "Invalid URI.");
+    }
+  }
+
+  @Override
+  public AuthHeaderProvider getAuthHeaderProvider() {
+    return session.getAuthHeaderProvider();
+  }
+
+  @Override
+  public String ifUnmodifiedSince() {
+    // TODO: last key time!
+    return null;
+  }
+
+  protected void setAndPersist(PersistedCrypto5Keys pck, CollectionKeys keys, long timestamp) {
+    session.config.setCollectionKeys(keys);
+    pck.persistKeys(keys);
+    pck.persistLastModified(timestamp);
+  }
+
+  /**
+   * Return collections where either the individual key has changed, or if the
+   * new default key is not the same as the old default key, where the
+   * collection is using the default key.
+   */
+  protected Set<String> collectionsToUpdate(CollectionKeys oldKeys, CollectionKeys newKeys) {
+    // These keys have explicitly changed; they definitely need updating.
+    Set<String> changedKeys = new HashSet<String>(CollectionKeys.differences(oldKeys, newKeys));
+
+    boolean defaultKeyChanged = true; // Most pessimistic is to assume default key has changed.
+    KeyBundle newDefaultKeyBundle = null;
+    try {
+      KeyBundle oldDefaultKeyBundle = oldKeys.defaultKeyBundle();
+      newDefaultKeyBundle = newKeys.defaultKeyBundle();
+      defaultKeyChanged = !oldDefaultKeyBundle.equals(newDefaultKeyBundle);
+    } catch (NoCollectionKeysSetException e) {
+      Logger.warn(LOG_TAG, "NoCollectionKeysSetException in EnsureCrypto5KeysStage.", e);
+    }
+
+    if (newDefaultKeyBundle == null) {
+      Logger.trace(LOG_TAG, "New default key not provided; returning changed individual keys.");
+      return changedKeys;
+    }
+
+    if (!defaultKeyChanged) {
+      Logger.trace(LOG_TAG, "New default key is the same as old default key; returning changed individual keys.");
+      return changedKeys;
+    }
+
+    // New keys have a different default/sync key; check known collections against the default key.
+    Logger.debug(LOG_TAG, "New default key is not the same as old default key.");
+    for (Stage stage : Stage.getNamedStages()) {
+      String name = stage.getRepositoryName();
+      if (!newKeys.keyBundleForCollectionIsNotDefault(name)) {
+        // Default key has changed, so this collection has changed.
+        changedKeys.add(name);
+      }
+    }
+
+    return changedKeys;
+  }
+
+  @Override
+  public void handleRequestSuccess(SyncStorageResponse response) {
+    // Take the timestamp from the response since it is later than the timestamp from info/collections.
+    long responseTimestamp = response.normalizedWeaveTimestamp();
+    CollectionKeys keys = new CollectionKeys();
+    try {
+      ExtendedJSONObject body = response.jsonObjectBody();
+      if (Logger.LOG_PERSONAL_INFORMATION) {
+        Logger.pii(LOG_TAG, "Fetched keys: " + body.toJSONString());
+      }
+      keys.setKeyPairsFromWBO(CryptoRecord.fromJSONRecord(body), session.config.syncKeyBundle);
+    } catch (Exception e) {
+      session.abort(e, "Invalid keys WBO.");
+      return;
+    }
+
+    PersistedCrypto5Keys pck = session.config.persistedCryptoKeys();
+    if (!pck.persistedKeysExist()) {
+      // New keys, and no old keys! Persist keys and server timestamp.
+      Logger.trace(LOG_TAG, "Setting fetched keys for this session; persisting fetched keys and last modified.");
+      setAndPersist(pck, keys, responseTimestamp);
+      session.advance();
+      return;
+    }
+
+    // New keys, but we had old keys.  Check for differences.
+    CollectionKeys oldKeys = pck.keys();
+    Set<String> changedCollections = collectionsToUpdate(oldKeys, keys);
+    if (!changedCollections.isEmpty()) {
+      // New keys, different from old keys.
+      Logger.trace(LOG_TAG, "Fetched keys are not the same as persisted keys; " +
+          "setting fetched keys for this session before resetting changed engines.");
+      setAndPersist(pck, keys, responseTimestamp);
+      session.resetStagesByName(changedCollections);
+      session.abort(null, "crypto/keys changed on server.");
+      return;
+    }
+
+    // New keys don't differ from old keys; persist timestamp and move on.
+    Logger.trace(LOG_TAG, "Fetched keys are the same as persisted keys; persisting only last modified.");
+    session.config.setCollectionKeys(oldKeys);
+    pck.persistLastModified(response.normalizedWeaveTimestamp());
+    session.advance();
+  }
+
+  @Override
+  public void handleRequestFailure(SyncStorageResponse response) {
+    if (retrying) {
+      // Should happen very rarely -- this means we uploaded our crypto/keys
+      // successfully, but failed to re-download.
+      session.handleHTTPError(response, "Failure while re-downloading already uploaded keys.");
+      return;
+    }
+
+    int statusCode = response.getStatusCode();
+    if (statusCode == 404) {
+      Logger.info(LOG_TAG, "Got 404 fetching keys.  Fresh starting since keys are missing on server.");
+      session.freshStart();
+      return;
+    }
+    session.handleHTTPError(response, "Failure fetching keys: got response status code " + statusCode);
+  }
+
+  @Override
+  public void handleRequestError(Exception ex) {
+    session.abort(ex, "Failure fetching keys.");
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FennecTabsServerSyncStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FennecTabsServerSyncStage.java
new file mode 100644
index 000000000..40a474ef4
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FennecTabsServerSyncStage.java
@@ -0,0 +1,40 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.android.FennecTabsRepository;
+import org.mozilla.gecko.sync.repositories.domain.TabsRecordFactory;
+import org.mozilla.gecko.sync.repositories.domain.VersionConstants;
+
+public class FennecTabsServerSyncStage extends ServerSyncStage {
+  private static final String COLLECTION = "tabs";
+
+  @Override
+  protected String getCollection() {
+    return COLLECTION;
+  }
+
+  @Override
+  protected String getEngineName() {
+    return COLLECTION;
+  }
+
+  @Override
+  public Integer getStorageVersion() {
+    return VersionConstants.TABS_ENGINE_VERSION;
+  }
+
+  @Override
+  protected Repository getLocalRepository() {
+    return new FennecTabsRepository(session.getClientsDelegate());
+  }
+
+  @Override
+  protected RecordFactory getRecordFactory() {
+    return new TabsRecordFactory();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FetchInfoCollectionsStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FetchInfoCollectionsStage.java
new file mode 100644
index 000000000..088321d5b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FetchInfoCollectionsStage.java
@@ -0,0 +1,44 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import java.net.URISyntaxException;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.InfoCollections;
+import org.mozilla.gecko.sync.delegates.JSONRecordFetchDelegate;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+public class FetchInfoCollectionsStage extends AbstractNonRepositorySyncStage {
+  public class StageInfoCollectionsDelegate implements JSONRecordFetchDelegate {
+
+    @Override
+    public void handleSuccess(ExtendedJSONObject global) {
+      session.config.infoCollections = new InfoCollections(global);
+      session.advance();
+    }
+
+    @Override
+    public void handleFailure(SyncStorageResponse response) {
+      session.handleHTTPError(response, "Failure fetching info/collections.");
+    }
+
+    @Override
+    public void handleError(Exception e) {
+      session.abort(e, "Failure fetching info/collections.");
+    }
+
+  }
+
+  @Override
+  public void execute() throws NoSuchStageException {
+    try {
+      session.fetchInfoCollections(new StageInfoCollectionsDelegate());
+    } catch (URISyntaxException e) {
+      session.abort(e, "Invalid URI.");
+    }
+  }
+
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FetchInfoConfigurationStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FetchInfoConfigurationStage.java
new file mode 100644
index 000000000..7f53c2739
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FetchInfoConfigurationStage.java
@@ -0,0 +1,59 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.InfoConfiguration;
+import org.mozilla.gecko.sync.JSONRecordFetcher;
+import org.mozilla.gecko.sync.delegates.JSONRecordFetchDelegate;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+/**
+ * Fetches configuration data from info/configurations endpoint.
+ */
+public class FetchInfoConfigurationStage extends AbstractNonRepositorySyncStage {
+    private final String configurationURL;
+    private final AuthHeaderProvider authHeaderProvider;
+
+    public FetchInfoConfigurationStage(final String configurationURL, final AuthHeaderProvider authHeaderProvider) {
+        super();
+        this.configurationURL = configurationURL;
+        this.authHeaderProvider = authHeaderProvider;
+    }
+
+    public class StageInfoConfigurationDelegate implements JSONRecordFetchDelegate {
+        @Override
+        public void handleSuccess(final ExtendedJSONObject result) {
+            session.config.infoConfiguration = new InfoConfiguration(result);
+            session.advance();
+        }
+
+        @Override
+        public void handleFailure(final SyncStorageResponse response) {
+            // Handle all non-404 failures upstream.
+            if (response.getStatusCode() != 404) {
+                session.handleHTTPError(response, "Failure fetching info/configuration");
+                return;
+            }
+
+            // End-point might not be available (404) if server is running an older version.
+            // We will use default config values in this case.
+            session.config.infoConfiguration = new InfoConfiguration();
+            session.advance();
+        }
+
+        @Override
+        public void handleError(final Exception e) {
+            session.abort(e, "Failure fetching info/configuration");
+        }
+    }
+    @Override
+    public void execute() {
+        final StageInfoConfigurationDelegate delegate = new StageInfoConfigurationDelegate();
+        final JSONRecordFetcher fetcher = new JSONRecordFetcher(configurationURL, authHeaderProvider);
+        fetcher.fetch(delegate);
+    }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FetchMetaGlobalStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FetchMetaGlobalStage.java
new file mode 100644
index 000000000..b4407b26b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FetchMetaGlobalStage.java
@@ -0,0 +1,79 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.GlobalSession;
+import org.mozilla.gecko.sync.InfoCollections;
+import org.mozilla.gecko.sync.MetaGlobal;
+import org.mozilla.gecko.sync.PersistedMetaGlobal;
+import org.mozilla.gecko.sync.delegates.MetaGlobalDelegate;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+
+public class FetchMetaGlobalStage extends AbstractNonRepositorySyncStage {
+  private static final String LOG_TAG = "FetchMetaGlobalStage";
+  private static final String META_COLLECTION = "meta";
+
+  public class StageMetaGlobalDelegate implements MetaGlobalDelegate {
+
+    private final GlobalSession session;
+    public StageMetaGlobalDelegate(GlobalSession session) {
+      this.session = session;
+    }
+
+    @Override
+    public void handleSuccess(MetaGlobal global, SyncStorageResponse response) {
+      Logger.trace(LOG_TAG, "Persisting fetched meta/global and last modified.");
+      PersistedMetaGlobal pmg = session.config.persistedMetaGlobal();
+      pmg.persistMetaGlobal(global);
+      // Take the timestamp from the response since it is later than the timestamp from info/collections.
+      pmg.persistLastModified(response.normalizedWeaveTimestamp());
+
+      session.processMetaGlobal(global);
+    }
+
+    @Override
+    public void handleFailure(SyncStorageResponse response) {
+      session.handleHTTPError(response, "Failure fetching meta/global.");
+    }
+
+    @Override
+    public void handleError(Exception e) {
+      session.abort(e, "Failure fetching meta/global.");
+    }
+
+    @Override
+    public void handleMissing(MetaGlobal global, SyncStorageResponse response) {
+      session.processMissingMetaGlobal(global);
+    }
+  }
+
+  @Override
+  public void execute() throws NoSuchStageException {
+    InfoCollections infoCollections = session.config.infoCollections;
+    if (infoCollections == null) {
+      session.abort(null, "No info/collections set in FetchMetaGlobalStage.");
+      return;
+    }
+
+    long lastModified = session.config.persistedMetaGlobal().lastModified();
+    if (!infoCollections.updateNeeded(META_COLLECTION, lastModified)) {
+      // Try to use our local collection keys for this session.
+      Logger.info(LOG_TAG, "Trying to use persisted meta/global for this session.");
+      MetaGlobal global = session.config.persistedMetaGlobal().metaGlobal(session.config.metaURL(), session.getAuthHeaderProvider());
+      if (global != null) {
+        Logger.info(LOG_TAG, "Using persisted meta/global for this session.");
+        session.processMetaGlobal(global); // Calls session.advance().
+        return;
+      }
+      Logger.info(LOG_TAG, "Failed to use persisted meta/global for this session.");
+    }
+
+    // We need an update: fetch or upload meta/global as necessary.
+    Logger.info(LOG_TAG, "Fetching fresh meta/global for this session.");
+    MetaGlobal global = new MetaGlobal(session.config.metaURL(), session.getAuthHeaderProvider());
+    global.fetch(new StageMetaGlobalDelegate(session));
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FormHistoryServerSyncStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FormHistoryServerSyncStage.java
new file mode 100644
index 000000000..0a5d974b8
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/FormHistoryServerSyncStage.java
@@ -0,0 +1,76 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import java.net.URISyntaxException;
+
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.repositories.ConstrainedServer11Repository;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.android.FormHistoryRepositorySession;
+import org.mozilla.gecko.sync.repositories.domain.FormHistoryRecord;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+import org.mozilla.gecko.sync.repositories.domain.VersionConstants;
+
+public class FormHistoryServerSyncStage extends ServerSyncStage {
+
+  // Eventually this kind of sync stage will be data-driven,
+  // and all this hard-coding can go away.
+  private static final String FORM_HISTORY_SORT          = "index";
+  // Sanity limit. Batch and total limit are the same for now, and will be adjusted
+  // once buffer and high water mark are in place. See Bug 730142.
+  private static final long FORM_HISTORY_BATCH_LIMIT = 5000;
+  private static final long FORM_HISTORY_TOTAL_LIMIT = 5000;
+
+  @Override
+  protected String getCollection() {
+    return "forms";
+  }
+
+  @Override
+  protected String getEngineName() {
+    return "forms";
+  }
+
+  @Override
+  public Integer getStorageVersion() {
+    return VersionConstants.FORMS_ENGINE_VERSION;
+  }
+
+  @Override
+  protected Repository getRemoteRepository() throws URISyntaxException {
+    String collection = getCollection();
+    return new ConstrainedServer11Repository(
+        collection,
+        session.config.storageURL(),
+        session.getAuthHeaderProvider(),
+        session.config.infoCollections,
+        session.config.infoConfiguration,
+        FORM_HISTORY_BATCH_LIMIT,
+        FORM_HISTORY_TOTAL_LIMIT,
+        FORM_HISTORY_SORT);
+  }
+
+  @Override
+  protected Repository getLocalRepository() {
+    return new FormHistoryRepositorySession.FormHistoryRepository();
+  }
+
+  public class FormHistoryRecordFactory extends RecordFactory {
+
+    @Override
+    public Record createRecord(Record record) {
+      FormHistoryRecord r = new FormHistoryRecord();
+      r.initFromEnvelope((CryptoRecord) record);
+      return r;
+    }
+  }
+
+  @Override
+  protected RecordFactory getRecordFactory() {
+    return new FormHistoryRecordFactory();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/GlobalSyncStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/GlobalSyncStage.java
new file mode 100644
index 000000000..6dee71f90
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/GlobalSyncStage.java
@@ -0,0 +1,93 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.mozilla.gecko.sync.GlobalSession;
+
+
+public interface GlobalSyncStage {
+  public static enum Stage {
+    idle,                       // Start state.
+    checkPreconditions,         // Preparation of the basics. TODO: clear status
+    fetchInfoCollections,       // Take a look at timestamps.
+    fetchInfoConfiguration,     // Fetch server upload limits
+    fetchMetaGlobal,
+    ensureKeysStage,
+    /*
+    ensureSpecialRecords,
+    updateEngineTimestamps,
+    */
+    syncClientsEngine(SyncClientsEngineStage.STAGE_NAME),
+    /*
+    processFirstSyncPref,
+    processClientCommands,
+    updateEnabledEngines,
+    */
+    syncTabs("tabs"),
+    syncPasswords("passwords"),
+    syncBookmarks("bookmarks"),
+    syncHistory("history"),
+    syncFormHistory("forms"),
+
+    uploadMetaGlobal,
+    completed;
+
+    // Maintain a mapping from names ("bookmarks") to Stage enumerations (syncBookmarks).
+    private static final Map<String, Stage> named = new HashMap<String, Stage>();
+    static {
+      for (Stage s : EnumSet.allOf(Stage.class)) {
+        if (s.getRepositoryName() != null) {
+          named.put(s.getRepositoryName(), s);
+        }
+      }
+    }
+
+    public static Stage byName(final String name) {
+      if (name == null) {
+        return null;
+      }
+      return named.get(name);
+    }
+
+    /**
+     * @return an immutable collection of Stages.
+     */
+    public static Collection<Stage> getNamedStages() {
+      return Collections.unmodifiableCollection(named.values());
+    }
+
+    // Each Stage tracks its repositoryName.
+    private final String repositoryName;
+    public String getRepositoryName() {
+      return repositoryName;
+    }
+
+    private Stage() {
+      this.repositoryName = null;
+    }
+
+    private Stage(final String name) {
+      this.repositoryName = name;
+    }
+  }
+
+  public void execute(GlobalSession session) throws NoSuchStageException;
+  public void resetLocal(GlobalSession session);
+  public void wipeLocal(GlobalSession session) throws Exception;
+
+  /**
+   * What storage version number this engine supports.
+   * <p>
+   * Used to generate a fresh meta/global record for upload.
+   * @return a version number or <code>null</code> to never include this engine in a fresh meta/global record.
+   */
+  public Integer getStorageVersion();
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/NoSuchStageException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/NoSuchStageException.java
new file mode 100644
index 000000000..14c9bb43e
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/NoSuchStageException.java
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+public class NoSuchStageException extends Exception {
+  private static final long serialVersionUID = 8338484472880746971L;
+  GlobalSyncStage.Stage stage;
+  public NoSuchStageException(GlobalSyncStage.Stage stage) {
+    this.stage = stage;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/PasswordsServerSyncStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/PasswordsServerSyncStage.java
new file mode 100644
index 000000000..c781ce2cc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/PasswordsServerSyncStage.java
@@ -0,0 +1,38 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.android.PasswordsRepositorySession;
+import org.mozilla.gecko.sync.repositories.domain.PasswordRecordFactory;
+import org.mozilla.gecko.sync.repositories.domain.VersionConstants;
+
+public class PasswordsServerSyncStage extends ServerSyncStage {
+  @Override
+  protected String getCollection() {
+    return "passwords";
+  }
+
+  @Override
+  protected String getEngineName() {
+    return "passwords";
+  }
+
+  @Override
+  public Integer getStorageVersion() {
+    return VersionConstants.PASSWORDS_ENGINE_VERSION;
+  }
+
+  @Override
+  protected Repository getLocalRepository() {
+    return new PasswordsRepositorySession.PasswordsRepository();
+  }
+
+  @Override
+  protected RecordFactory getRecordFactory() {
+    return new PasswordRecordFactory();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/SafeConstrainedServer11Repository.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/SafeConstrainedServer11Repository.java
new file mode 100644
index 000000000..733c887f0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/SafeConstrainedServer11Repository.java
@@ -0,0 +1,110 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import java.net.URISyntaxException;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.InfoCollections;
+import org.mozilla.gecko.sync.InfoConfiguration;
+import org.mozilla.gecko.sync.InfoCounts;
+import org.mozilla.gecko.sync.JSONRecordFetcher;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.repositories.ConstrainedServer11Repository;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.Server11RepositorySession;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+
+import android.content.Context;
+
+/**
+ * This is a constrained repository -- one which fetches a limited number
+ * of records -- that additionally refuses to sync if the limit will
+ * be exceeded on a first sync by the number of records on the server.
+ *
+ * You must pass an {@link InfoCounts} instance, which will be interrogated
+ * in the event of a first sync.
+ *
+ * "First sync" means that our sync timestamp is not greater than zero.
+ */
+public class SafeConstrainedServer11Repository extends ConstrainedServer11Repository {
+
+  // This can be lazily evaluated if we need it.
+  private final JSONRecordFetcher countFetcher;
+
+  public SafeConstrainedServer11Repository(String collection,
+                                           String storageURL,
+                                           AuthHeaderProvider authHeaderProvider,
+                                           InfoCollections infoCollections,
+                                           InfoConfiguration infoConfiguration,
+                                           long batchLimit,
+                                           long totalLimit,
+                                           String sort,
+                                           JSONRecordFetcher countFetcher)
+    throws URISyntaxException {
+    super(collection, storageURL, authHeaderProvider, infoCollections, infoConfiguration,
+            batchLimit, totalLimit, sort);
+    if (countFetcher == null) {
+      throw new IllegalArgumentException("countFetcher must not be null");
+    }
+    this.countFetcher = countFetcher;
+  }
+
+  @Override
+  public void createSession(RepositorySessionCreationDelegate delegate,
+                            Context context) {
+    delegate.onSessionCreated(new CountCheckingServer11RepositorySession(this, this.getDefaultBatchLimit()));
+  }
+
+  public class CountCheckingServer11RepositorySession extends Server11RepositorySession {
+    private static final String LOG_TAG = "CountCheckingServer11RepositorySession";
+
+    /**
+     * The session will report no data available if this is a first sync
+     * and the server has more data available than this limit.
+     */
+    private final long fetchLimit;
+
+    public CountCheckingServer11RepositorySession(Repository repository, long fetchLimit) {
+      super(repository);
+      this.fetchLimit = fetchLimit;
+    }
+
+    @Override
+    public boolean shouldSkip() {
+      // If this is a first sync, verify that we aren't going to blow through our limit.
+      final long lastSyncTimestamp = getLastSyncTimestamp();
+      if (lastSyncTimestamp > 0) {
+        Logger.info(LOG_TAG, "Collection " + collection + " has already had a first sync: " +
+            "timestamp is " + lastSyncTimestamp  + "; " +
+            "ignoring any updated counts and syncing as usual.");
+      } else {
+        Logger.info(LOG_TAG, "Collection " + collection + " is starting a first sync; checking counts.");
+
+        final InfoCounts counts;
+        try {
+          // This'll probably be the same object, but best to obey the API.
+          counts = new InfoCounts(countFetcher.fetchBlocking());
+        } catch (Exception e) {
+          Logger.warn(LOG_TAG, "Skipping " + collection + " until we can fetch counts.", e);
+          return true;
+        }
+
+        Integer c = counts.getCount(collection);
+        if (c == null) {
+          Logger.info(LOG_TAG, "Fetched counts does not include collection " + collection + "; syncing as usual.");
+          return false;
+        }
+
+        Logger.info(LOG_TAG, "First sync for " + collection + ": " + c + " items.");
+        if (c > fetchLimit) {
+          Logger.warn(LOG_TAG, "Too many items to sync safely. Skipping.");
+          return true;
+        }
+      }
+      return super.shouldSkip();
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/ServerSyncStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/ServerSyncStage.java
new file mode 100644
index 000000000..733e69da5
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/ServerSyncStage.java
@@ -0,0 +1,627 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import android.content.Context;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.EngineSettings;
+import org.mozilla.gecko.sync.GlobalSession;
+import org.mozilla.gecko.sync.HTTPFailureException;
+import org.mozilla.gecko.sync.MetaGlobalException;
+import org.mozilla.gecko.sync.NoCollectionKeysSetException;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+import org.mozilla.gecko.sync.SynchronizerConfiguration;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.delegates.WipeServerDelegate;
+import org.mozilla.gecko.sync.middleware.Crypto5MiddlewareRepository;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.BaseResource;
+import org.mozilla.gecko.sync.net.SyncStorageRequest;
+import org.mozilla.gecko.sync.net.SyncStorageRequestDelegate;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+import org.mozilla.gecko.sync.repositories.InactiveSessionException;
+import org.mozilla.gecko.sync.repositories.InvalidSessionTransitionException;
+import org.mozilla.gecko.sync.repositories.RecordFactory;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+import org.mozilla.gecko.sync.repositories.RepositorySessionBundle;
+import org.mozilla.gecko.sync.repositories.Server11Repository;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionBeginDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionCreationDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionWipeDelegate;
+import org.mozilla.gecko.sync.synchronizer.ServerLocalSynchronizer;
+import org.mozilla.gecko.sync.synchronizer.Synchronizer;
+import org.mozilla.gecko.sync.synchronizer.SynchronizerDelegate;
+import org.mozilla.gecko.sync.synchronizer.SynchronizerSession;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+
+/**
+ * Fetch from a server collection into a local repository, encrypting
+ * and decrypting along the way.
+ *
+ * @author rnewman
+ *
+ */
+public abstract class ServerSyncStage extends AbstractSessionManagingSyncStage implements SynchronizerDelegate {
+
+  protected static final String LOG_TAG = "ServerSyncStage";
+
+  protected long stageStartTimestamp = -1;
+  protected long stageCompleteTimestamp = -1;
+
+  /**
+   * Override these in your subclasses.
+   *
+   * @return true if this stage should be executed.
+   * @throws MetaGlobalException
+   */
+  protected boolean isEnabled() throws MetaGlobalException {
+    EngineSettings engineSettings = null;
+    try {
+       engineSettings = getEngineSettings();
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Unable to get engine settings for " + this + ": fetching config failed.", e);
+      // Fall through; null engineSettings will pass below.
+    }
+
+    // We can be disabled by the server's meta/global record, or malformed in the server's meta/global record,
+    // or by the user manually in Sync Settings.
+    // We catch the subclasses of MetaGlobalException to trigger various resets and wipes in execute().
+    boolean enabledInMetaGlobal = session.isEngineRemotelyEnabled(this.getEngineName(), engineSettings);
+
+    // Check for manual changes to engines by the user.
+    checkAndUpdateUserSelectedEngines(enabledInMetaGlobal);
+
+    // Check for changes on the server.
+    if (!enabledInMetaGlobal) {
+      Logger.debug(LOG_TAG, "Stage " + this.getEngineName() + " disabled by server meta/global.");
+      return false;
+    }
+
+    // We can also be disabled just for this sync.
+    boolean enabledThisSync = session.isEngineLocallyEnabled(this.getEngineName()); // For ServerSyncStage, stage name == engine name.
+    if (!enabledThisSync) {
+      Logger.debug(LOG_TAG, "Stage " + this.getEngineName() + " disabled just for this sync.");
+    }
+    return enabledThisSync;
+  }
+
+  /**
+   * Compares meta/global engine state to user selected engines from Sync
+   * Settings and throws an exception if they don't match and meta/global needs
+   * to be updated.
+   *
+   * @param enabledInMetaGlobal
+   *          boolean of engine sync state in meta/global
+   * @throws MetaGlobalException
+   *           if engine sync state has been changed in Sync Settings, with new
+   *           engine sync state.
+   */
+  protected void checkAndUpdateUserSelectedEngines(boolean enabledInMetaGlobal) throws MetaGlobalException {
+    Map<String, Boolean> selectedEngines = session.config.userSelectedEngines;
+    String thisEngine = this.getEngineName();
+
+    if (selectedEngines != null && selectedEngines.containsKey(thisEngine)) {
+      boolean enabledInSelection = selectedEngines.get(thisEngine);
+      if (enabledInMetaGlobal != enabledInSelection) {
+        // Engine enable state has been changed by the user.
+        Logger.debug(LOG_TAG, "Engine state has been changed by user. Throwing exception.");
+        throw new MetaGlobalException.MetaGlobalEngineStateChangedException(enabledInSelection);
+      }
+    }
+  }
+
+  protected EngineSettings getEngineSettings() throws NonObjectJSONException, IOException {
+    Integer version = getStorageVersion();
+    if (version == null) {
+      Logger.warn(LOG_TAG, "null storage version for " + this + "; using version 0.");
+      version = 0;
+    }
+
+    SynchronizerConfiguration config = this.getConfig();
+    if (config == null) {
+      return new EngineSettings(null, version);
+    }
+    return new EngineSettings(config.syncID, version);
+  }
+
+  protected abstract String getCollection();
+  protected abstract String getEngineName();
+  protected abstract Repository getLocalRepository();
+  protected abstract RecordFactory getRecordFactory();
+
+  // Override this in subclasses.
+  protected Repository getRemoteRepository() throws URISyntaxException {
+    String collection = getCollection();
+    return new Server11Repository(collection,
+                                  session.config.storageURL(),
+                                  session.getAuthHeaderProvider(),
+                                  session.config.infoCollections,
+                                  session.config.infoConfiguration);
+  }
+
+  /**
+   * Return a Crypto5Middleware-wrapped Server11Repository.
+   *
+   * @throws NoCollectionKeysSetException
+   * @throws URISyntaxException
+   */
+  protected Repository wrappedServerRepo() throws NoCollectionKeysSetException, URISyntaxException {
+    String collection = this.getCollection();
+    KeyBundle collectionKey = session.keyBundleForCollection(collection);
+    Crypto5MiddlewareRepository cryptoRepo = new Crypto5MiddlewareRepository(getRemoteRepository(), collectionKey);
+    cryptoRepo.recordFactory = getRecordFactory();
+    return cryptoRepo;
+  }
+
+  protected String bundlePrefix() {
+    return this.getCollection() + ".";
+  }
+
+  protected SynchronizerConfiguration getConfig() throws NonObjectJSONException, IOException {
+    return new SynchronizerConfiguration(session.config.getBranch(bundlePrefix()));
+  }
+
+  protected void persistConfig(SynchronizerConfiguration synchronizerConfiguration) {
+    synchronizerConfiguration.persist(session.config.getBranch(bundlePrefix()));
+  }
+
+  public Synchronizer getConfiguredSynchronizer(GlobalSession session) throws NoCollectionKeysSetException, URISyntaxException, NonObjectJSONException, IOException {
+    Repository remote = wrappedServerRepo();
+
+    Synchronizer synchronizer = new ServerLocalSynchronizer();
+    synchronizer.repositoryA = remote;
+    synchronizer.repositoryB = this.getLocalRepository();
+    synchronizer.load(getConfig());
+
+    return synchronizer;
+  }
+
+  /**
+   * Reset timestamps.
+   */
+  @Override
+  protected void resetLocal() {
+    resetLocalWithSyncID(null);
+  }
+
+  /**
+   * Reset timestamps and possibly set syncID.
+   * @param syncID if non-null, new syncID to persist.
+   */
+  protected void resetLocalWithSyncID(String syncID) {
+    // Clear both timestamps.
+    SynchronizerConfiguration config;
+    try {
+      config = this.getConfig();
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Unable to reset " + this + ": fetching config failed.", e);
+      return;
+    }
+
+    if (syncID != null) {
+      config.syncID = syncID;
+      Logger.info(LOG_TAG, "Setting syncID for " + this + " to '" + syncID + "'.");
+    }
+    config.localBundle.setTimestamp(0L);
+    config.remoteBundle.setTimestamp(0L);
+    persistConfig(config);
+    Logger.info(LOG_TAG, "Reset timestamps for " + this);
+  }
+
+  // Not thread-safe. Use with caution.
+  private class WipeWaiter {
+    public boolean sessionSucceeded = true;
+    public boolean wipeSucceeded = true;
+    public Exception error;
+
+    public void notify(Exception e, boolean sessionSucceeded) {
+      this.sessionSucceeded = sessionSucceeded;
+      this.wipeSucceeded = false;
+      this.error = e;
+      this.notify();
+    }
+  }
+
+  /**
+   * Synchronously wipe this stage by instantiating a local repository session
+   * and wiping that.
+   * <p>
+   * Logs and re-throws an exception on failure.
+   */
+  @Override
+  protected void wipeLocal() throws Exception {
+    // Reset, then clear data.
+    this.resetLocal();
+
+    final WipeWaiter monitor = new WipeWaiter();
+    final Context context = session.getContext();
+    final Repository r = this.getLocalRepository();
+
+    final Runnable doWipe = new Runnable() {
+      @Override
+      public void run() {
+        r.createSession(new RepositorySessionCreationDelegate() {
+
+          @Override
+          public void onSessionCreated(final RepositorySession session) {
+            try {
+              session.begin(new RepositorySessionBeginDelegate() {
+
+                @Override
+                public void onBeginSucceeded(final RepositorySession session) {
+                  session.wipe(new RepositorySessionWipeDelegate() {
+                    @Override
+                    public void onWipeSucceeded() {
+                      try {
+                        session.finish(new RepositorySessionFinishDelegate() {
+
+                          @Override
+                          public void onFinishSucceeded(RepositorySession session,
+                                                        RepositorySessionBundle bundle) {
+                            // Hurrah.
+                            synchronized (monitor) {
+                              monitor.notify();
+                            }
+                          }
+
+                          @Override
+                          public void onFinishFailed(Exception ex) {
+                            // Assume that no finish => no wipe.
+                            synchronized (monitor) {
+                              monitor.notify(ex, true);
+                            }
+                          }
+
+                          @Override
+                          public RepositorySessionFinishDelegate deferredFinishDelegate(ExecutorService executor) {
+                            return this;
+                          }
+                        });
+                      } catch (InactiveSessionException e) {
+                        // Cannot happen. Call for safety.
+                        synchronized (monitor) {
+                          monitor.notify(e, true);
+                        }
+                      }
+                    }
+
+                    @Override
+                    public void onWipeFailed(Exception ex) {
+                      session.abort();
+                      synchronized (monitor) {
+                        monitor.notify(ex, true);
+                      }
+                    }
+
+                    @Override
+                    public RepositorySessionWipeDelegate deferredWipeDelegate(ExecutorService executor) {
+                      return this;
+                    }
+                  });
+                }
+
+                @Override
+                public void onBeginFailed(Exception ex) {
+                  session.abort();
+                  synchronized (monitor) {
+                    monitor.notify(ex, true);
+                  }
+                }
+
+                @Override
+                public RepositorySessionBeginDelegate deferredBeginDelegate(ExecutorService executor) {
+                  return this;
+                }
+              });
+            } catch (InvalidSessionTransitionException e) {
+              session.abort();
+              synchronized (monitor) {
+                monitor.notify(e, true);
+              }
+            }
+          }
+
+          @Override
+          public void onSessionCreateFailed(Exception ex) {
+            synchronized (monitor) {
+              monitor.notify(ex, false);
+            }
+          }
+
+          @Override
+          public RepositorySessionCreationDelegate deferredCreationDelegate() {
+            return this;
+          }
+        }, context);
+      }
+    };
+
+    final Thread wiping = new Thread(doWipe);
+    synchronized (monitor) {
+      wiping.start();
+      try {
+        monitor.wait();
+      } catch (InterruptedException e) {
+        Logger.error(LOG_TAG, "Wipe interrupted.");
+      }
+    }
+
+    if (!monitor.sessionSucceeded) {
+      Logger.error(LOG_TAG, "Failed to create session for wipe.");
+      throw monitor.error;
+    }
+
+    if (!monitor.wipeSucceeded) {
+      Logger.error(LOG_TAG, "Failed to wipe session.");
+      throw monitor.error;
+    }
+
+    Logger.info(LOG_TAG, "Wiping stage complete.");
+  }
+
+  /**
+   * Asynchronously wipe collection on server.
+   */
+  protected void wipeServer(final AuthHeaderProvider authHeaderProvider, final WipeServerDelegate wipeDelegate) {
+    SyncStorageRequest request;
+
+    try {
+      request = new SyncStorageRequest(session.config.collectionURI(getCollection()));
+    } catch (URISyntaxException ex) {
+      Logger.warn(LOG_TAG, "Invalid URI in wipeServer.");
+      wipeDelegate.onWipeFailed(ex);
+      return;
+    }
+
+    request.delegate = new SyncStorageRequestDelegate() {
+
+      @Override
+      public String ifUnmodifiedSince() {
+        return null;
+      }
+
+      @Override
+      public void handleRequestSuccess(SyncStorageResponse response) {
+        BaseResource.consumeEntity(response);
+        resetLocal();
+        wipeDelegate.onWiped(response.normalizedWeaveTimestamp());
+      }
+
+      @Override
+      public void handleRequestFailure(SyncStorageResponse response) {
+        Logger.warn(LOG_TAG, "Got request failure " + response.getStatusCode() + " in wipeServer.");
+        // Process HTTP failures here to pick up backoffs, etc.
+        session.interpretHTTPFailure(response.httpResponse());
+        BaseResource.consumeEntity(response); // The exception thrown should not need the body of the response.
+        wipeDelegate.onWipeFailed(new HTTPFailureException(response));
+      }
+
+      @Override
+      public void handleRequestError(Exception ex) {
+        Logger.warn(LOG_TAG, "Got exception in wipeServer.", ex);
+        wipeDelegate.onWipeFailed(ex);
+      }
+
+      @Override
+      public AuthHeaderProvider getAuthHeaderProvider() {
+        return authHeaderProvider;
+      }
+    };
+
+    request.delete();
+  }
+
+  /**
+   * Synchronously wipe the server.
+   * <p>
+   * Logs and re-throws an exception on failure.
+   */
+  public void wipeServer(final GlobalSession session) throws Exception {
+    this.session = session;
+
+    final WipeWaiter monitor = new WipeWaiter();
+
+    final Runnable doWipe = new Runnable() {
+      @Override
+      public void run() {
+        wipeServer(session.getAuthHeaderProvider(), new WipeServerDelegate() {
+          @Override
+          public void onWiped(long timestamp) {
+            synchronized (monitor) {
+              monitor.notify();
+            }
+          }
+
+          @Override
+          public void onWipeFailed(Exception e) {
+            synchronized (monitor) {
+              monitor.notify(e, false);
+            }
+          }
+        });
+      }
+    };
+
+    final Thread wiping = new Thread(doWipe);
+    synchronized (monitor) {
+      wiping.start();
+      try {
+        monitor.wait();
+      } catch (InterruptedException e) {
+        Logger.error(LOG_TAG, "Server wipe interrupted.");
+      }
+    }
+
+    if (!monitor.wipeSucceeded) {
+      Logger.error(LOG_TAG, "Failed to wipe server.");
+      throw monitor.error;
+    }
+
+    Logger.info(LOG_TAG, "Wiping server complete.");
+  }
+
+  @Override
+  public void execute() throws NoSuchStageException {
+    final String name = getEngineName();
+    Logger.debug(LOG_TAG, "Starting execute for " + name);
+
+    stageStartTimestamp = System.currentTimeMillis();
+
+    try {
+      if (!this.isEnabled()) {
+        Logger.info(LOG_TAG, "Skipping stage " + name + ".");
+        session.advance();
+        return;
+      }
+    } catch (MetaGlobalException.MetaGlobalMalformedSyncIDException e) {
+      // Bad engine syncID. This should never happen. Wipe the server.
+      try {
+        session.recordForMetaGlobalUpdate(name, new EngineSettings(Utils.generateGuid(), this.getStorageVersion()));
+        Logger.info(LOG_TAG, "Wiping server because malformed engine sync ID was found in meta/global.");
+        wipeServer(session);
+        Logger.info(LOG_TAG, "Wiped server after malformed engine sync ID found in meta/global.");
+      } catch (Exception ex) {
+        session.abort(ex, "Failed to wipe server after malformed engine sync ID found in meta/global.");
+      }
+    } catch (MetaGlobalException.MetaGlobalMalformedVersionException e) {
+      // Bad engine version. This should never happen. Wipe the server.
+      try {
+        session.recordForMetaGlobalUpdate(name, new EngineSettings(Utils.generateGuid(), this.getStorageVersion()));
+        Logger.info(LOG_TAG, "Wiping server because malformed engine version was found in meta/global.");
+        wipeServer(session);
+        Logger.info(LOG_TAG, "Wiped server after malformed engine version found in meta/global.");
+      } catch (Exception ex) {
+        session.abort(ex, "Failed to wipe server after malformed engine version found in meta/global.");
+      }
+    } catch (MetaGlobalException.MetaGlobalStaleClientSyncIDException e) {
+      // Our syncID is wrong. Reset client and take the server syncID.
+      Logger.warn(LOG_TAG, "Remote engine syncID different from local engine syncID:" +
+                           " resetting local engine and assuming remote engine syncID.");
+      this.resetLocalWithSyncID(e.serverSyncID);
+    } catch (MetaGlobalException.MetaGlobalEngineStateChangedException e) {
+      boolean isEnabled = e.isEnabled;
+      if (!isEnabled) {
+        // Engine has been disabled; update meta/global with engine removal for upload.
+        session.removeEngineFromMetaGlobal(name);
+        session.config.declinedEngineNames.add(name);
+      } else {
+        session.config.declinedEngineNames.remove(name);
+        // Add engine with new syncID to meta/global for upload.
+        String newSyncID = Utils.generateGuid();
+        session.recordForMetaGlobalUpdate(name, new EngineSettings(newSyncID, this.getStorageVersion()));
+        // Update SynchronizerConfiguration w/ new engine syncID.
+        this.resetLocalWithSyncID(newSyncID);
+      }
+      try {
+        // Engine sync status has changed. Wipe server.
+        Logger.warn(LOG_TAG, "Wiping server because engine sync state changed.");
+        wipeServer(session);
+        Logger.warn(LOG_TAG, "Wiped server because engine sync state changed.");
+      } catch (Exception ex) {
+        session.abort(ex, "Failed to wipe server after engine sync state changed");
+      }
+      if (!isEnabled) {
+        Logger.warn(LOG_TAG, "Stage has been disabled. Advancing to next stage.");
+        session.advance();
+        return;
+      }
+    } catch (MetaGlobalException e) {
+      session.abort(e, "Inappropriate meta/global; refusing to execute " + name + " stage.");
+      return;
+    }
+
+    Synchronizer synchronizer;
+    try {
+      synchronizer = this.getConfiguredSynchronizer(session);
+    } catch (NoCollectionKeysSetException e) {
+      session.abort(e, "No CollectionKeys.");
+      return;
+    } catch (URISyntaxException e) {
+      session.abort(e, "Invalid URI syntax for server repository.");
+      return;
+    } catch (NonObjectJSONException | IOException e) {
+      session.abort(e, "Invalid persisted JSON for config.");
+      return;
+    }
+
+    Logger.debug(LOG_TAG, "Invoking synchronizer.");
+    synchronizer.synchronize(session.getContext(), this);
+    Logger.debug(LOG_TAG, "Reached end of execute.");
+  }
+
+  /**
+   * Express the duration taken by this stage as a String, like "0.56 seconds".
+   *
+   * @return formatted string.
+   */
+  protected String getStageDurationString() {
+    return Utils.formatDuration(stageStartTimestamp, stageCompleteTimestamp);
+  }
+
+  /**
+   * We synced this engine!  Persist timestamps and advance the session.
+   *
+   * @param synchronizer the <code>Synchronizer</code> that succeeded.
+   */
+  @Override
+  public void onSynchronized(Synchronizer synchronizer) {
+    stageCompleteTimestamp = System.currentTimeMillis();
+    Logger.debug(LOG_TAG, "onSynchronized.");
+
+    SynchronizerConfiguration newConfig = synchronizer.save();
+    if (newConfig != null) {
+      persistConfig(newConfig);
+    } else {
+      Logger.warn(LOG_TAG, "Didn't get configuration from synchronizer after success.");
+    }
+
+    final SynchronizerSession synchronizerSession = synchronizer.getSynchronizerSession();
+    int inboundCount = synchronizerSession.getInboundCount();
+    int outboundCount = synchronizerSession.getOutboundCount();
+    Logger.info(LOG_TAG, "Stage " + getEngineName() +
+        " received " + inboundCount + " and sent " + outboundCount +
+        " records in " + getStageDurationString() + ".");
+    Logger.info(LOG_TAG, "Advancing session.");
+    session.advance();
+  }
+
+  /**
+   * We failed to sync this engine! Do not persist timestamps (which means that
+   * the next sync will include this sync's data), but do advance the session
+   * (if we didn't get a Retry-After header).
+   *
+   * @param synchronizer the <code>Synchronizer</code> that failed.
+   */
+  @Override
+  public void onSynchronizeFailed(Synchronizer synchronizer,
+                                  Exception lastException, String reason) {
+    stageCompleteTimestamp = System.currentTimeMillis();
+    Logger.warn(LOG_TAG, "Synchronize failed: " + reason, lastException);
+
+    // This failure could be due to a 503 or a 401 and it could have headers.
+    // Interrogate the headers but only abort the global session if Retry-After header is set.
+    if (lastException instanceof HTTPFailureException) {
+      SyncStorageResponse response = ((HTTPFailureException)lastException).response;
+      if (response.retryAfterInSeconds() > 0) {
+        session.handleHTTPError(response, reason); // Calls session.abort().
+        return;
+      } else {
+        session.interpretHTTPFailure(response.httpResponse()); // Does not call session.abort().
+      }
+    }
+
+    Logger.info(LOG_TAG, "Advancing session even though stage failed (took " + getStageDurationString() +
+        "). Timestamps not persisted.");
+    session.advance();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/SyncClientsEngineStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/SyncClientsEngineStage.java
new file mode 100644
index 000000000..04d3e7ce2
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/SyncClientsEngineStage.java
@@ -0,0 +1,691 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+import android.accounts.Account;
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.text.TextUtils;
+import android.util.Log;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.AppConstants;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.FxAccountClient;
+import org.mozilla.gecko.background.fxa.FxAccountClient20;
+import org.mozilla.gecko.background.fxa.FxAccountClientException;
+import org.mozilla.gecko.fxa.FirefoxAccounts;
+import org.mozilla.gecko.fxa.authenticator.AndroidFxAccount;
+import org.mozilla.gecko.sync.CommandProcessor;
+import org.mozilla.gecko.sync.CommandProcessor.Command;
+import org.mozilla.gecko.sync.CryptoRecord;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.HTTPFailureException;
+import org.mozilla.gecko.sync.NoCollectionKeysSetException;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.crypto.CryptoException;
+import org.mozilla.gecko.sync.crypto.KeyBundle;
+import org.mozilla.gecko.sync.delegates.ClientsDataDelegate;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.BaseResource;
+import org.mozilla.gecko.sync.net.SyncStorageCollectionRequest;
+import org.mozilla.gecko.sync.net.SyncStorageRecordRequest;
+import org.mozilla.gecko.sync.net.SyncStorageResponse;
+import org.mozilla.gecko.sync.net.WBOCollectionRequestDelegate;
+import org.mozilla.gecko.sync.net.WBORequestDelegate;
+import org.mozilla.gecko.sync.repositories.NullCursorException;
+import org.mozilla.gecko.sync.repositories.android.ClientsDatabaseAccessor;
+import org.mozilla.gecko.sync.repositories.android.RepoUtils;
+import org.mozilla.gecko.sync.repositories.domain.ClientRecord;
+import org.mozilla.gecko.sync.repositories.domain.ClientRecordFactory;
+import org.mozilla.gecko.sync.repositories.domain.VersionConstants;
+
+import ch.boye.httpclientandroidlib.HttpStatus;
+
+public class SyncClientsEngineStage extends AbstractSessionManagingSyncStage {
+  private static final String LOG_TAG = "SyncClientsEngineStage";
+
+  public static final String COLLECTION_NAME       = "clients";
+  public static final String STAGE_NAME            = COLLECTION_NAME;
+  public static final int CLIENTS_TTL_REFRESH      = 604800000;   // 7 days in milliseconds.
+  public static final int MAX_UPLOAD_FAILURE_COUNT = 5;
+  public static final long NOTIFY_TAB_SENT_TTL_SECS = TimeUnit.SECONDS.convert(1L, TimeUnit.HOURS); // 1 hour
+
+  protected final ClientRecordFactory factory = new ClientRecordFactory();
+  protected ClientUploadDelegate clientUploadDelegate;
+  protected ClientDownloadDelegate clientDownloadDelegate;
+
+  // Be sure to use this safely via getClientsDatabaseAccessor/closeDataAccessor.
+  protected ClientsDatabaseAccessor db;
+
+  protected volatile boolean shouldWipe;
+  protected volatile boolean shouldUploadLocalRecord;     // Set if, e.g., we received commands or need to refresh our version.
+  protected final AtomicInteger uploadAttemptsCount = new AtomicInteger();
+  protected final List<ClientRecord> modifiedClientsToUpload = new ArrayList<ClientRecord>();
+
+  protected int getClientsCount() {
+    return getClientsDatabaseAccessor().clientsCount();
+  }
+
+  protected synchronized ClientsDatabaseAccessor getClientsDatabaseAccessor() {
+    if (db == null) {
+      db = new ClientsDatabaseAccessor(session.getContext());
+    }
+    return db;
+  }
+
+  protected synchronized void closeDataAccessor() {
+    if (db == null) {
+      return;
+    }
+    db.close();
+    db = null;
+  }
+
+  /**
+   * The following two delegates, ClientDownloadDelegate and ClientUploadDelegate
+   * are both triggered in a chain, starting when execute() calls
+   * downloadClientRecords().
+   *
+   * Client records are downloaded using a get() request. Upon success of the
+   * get() request, the local client record is uploaded.
+   *
+   * @author Marina Samuel
+   *
+   */
+  public class ClientDownloadDelegate extends WBOCollectionRequestDelegate {
+
+    // We use this on each WBO, so lift it out.
+    final ClientsDataDelegate clientsDelegate = session.getClientsDelegate();
+    boolean localAccountGUIDDownloaded = false;
+
+    @Override
+    public AuthHeaderProvider getAuthHeaderProvider() {
+      return session.getAuthHeaderProvider();
+    }
+
+    @Override
+    public String ifUnmodifiedSince() {
+      // TODO last client download time?
+      return null;
+    }
+
+    @Override
+    public void handleRequestSuccess(SyncStorageResponse response) {
+
+      // Hang onto the server's last modified timestamp to use
+      // in X-If-Unmodified-Since for upload.
+      session.config.persistServerClientsTimestamp(response.normalizedWeaveTimestamp());
+      BaseResource.consumeEntity(response);
+
+      // Wipe the clients table if it still hasn't been wiped but needs to be.
+      wipeAndStore(null);
+
+      // If we successfully downloaded all records but ours was not one of them
+      // then reset the timestamp.
+      if (!localAccountGUIDDownloaded) {
+        Logger.info(LOG_TAG, "Local client GUID does not exist on the server. Upload timestamp will be reset.");
+        session.config.persistServerClientRecordTimestamp(0);
+      }
+      localAccountGUIDDownloaded = false;
+
+      final int clientsCount;
+      try {
+        clientsCount = getClientsCount();
+      } finally {
+        // Close the database to clear cached readableDatabase/writableDatabase
+        // after we've completed our last transaction (db.store()).
+        closeDataAccessor();
+      }
+
+      Logger.debug(LOG_TAG, "Database contains " + clientsCount + " clients.");
+      Logger.debug(LOG_TAG, "Server response asserts " + response.weaveRecords() + " records.");
+
+      // TODO: persist the response timestamp to know whether to download next time (Bug 726055).
+      clientUploadDelegate = new ClientUploadDelegate();
+      clientsDelegate.setClientsCount(clientsCount);
+
+      // If we upload remote records, checkAndUpload() will be called upon
+      // upload success in the delegate. Otherwise call checkAndUpload() now.
+      if (modifiedClientsToUpload.size() > 0) {
+        // modifiedClientsToUpload is cleared in uploadRemoteRecords, save what we need here
+        final List<String> devicesToNotify = new ArrayList<>();
+        for (ClientRecord record : modifiedClientsToUpload) {
+          if (!TextUtils.isEmpty(record.fxaDeviceId)) {
+            devicesToNotify.add(record.fxaDeviceId);
+          }
+        }
+
+        // This method is synchronous, there's no risk of notifying the clients
+        // before we actually uploaded the records
+        uploadRemoteRecords();
+
+        // Notify the clients who got their record written
+        notifyClients(devicesToNotify);
+
+        return;
+      }
+      checkAndUpload();
+    }
+
+    private void notifyClients(final List<String> devicesToNotify) {
+      final ExecutorService executor = Executors.newSingleThreadExecutor();
+      final Context context = session.getContext();
+      final Account account = FirefoxAccounts.getFirefoxAccount(context);
+      if (account == null) {
+        Log.e(LOG_TAG, "Can't notify other clients: no account");
+        return;
+      }
+      final AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+      final ExtendedJSONObject payload = createNotifyDevicesPayload();
+
+      final byte[] sessionToken;
+      try {
+        sessionToken = fxAccount.getSessionToken();
+      } catch (AndroidFxAccount.InvalidFxAState invalidFxAState) {
+        Log.e(LOG_TAG, "Could not get session token", invalidFxAState);
+        return;
+      }
+
+      // API doc : https://github.com/mozilla/fxa-auth-server/blob/master/docs/api.md#post-v1accountdevicesnotify
+      final FxAccountClient fxAccountClient = new FxAccountClient20(fxAccount.getAccountServerURI(), executor);
+      fxAccountClient.notifyDevices(sessionToken, devicesToNotify, payload, NOTIFY_TAB_SENT_TTL_SECS, new FxAccountClient20.RequestDelegate<ExtendedJSONObject>() {
+        @Override
+        public void handleError(Exception e) {
+          Log.e(LOG_TAG, "Error while notifying devices", e);
+        }
+
+        @Override
+        public void handleFailure(FxAccountClientException.FxAccountClientRemoteException e) {
+          Log.e(LOG_TAG, "Error while notifying devices", e);
+        }
+
+        @Override
+        public void handleSuccess(ExtendedJSONObject result) {
+          Log.i(LOG_TAG, devicesToNotify.size() + " devices notified");
+        }
+      });
+    }
+
+    @NonNull
+    @SuppressWarnings("unchecked")
+    private ExtendedJSONObject createNotifyDevicesPayload() {
+      final ExtendedJSONObject payload = new ExtendedJSONObject();
+      payload.put("version", 1);
+      payload.put("command", "sync:collection_changed");
+      final ExtendedJSONObject data = new ExtendedJSONObject();
+      final JSONArray collections = new JSONArray();
+      collections.add("clients");
+      data.put("collections", collections);
+      payload.put("data", data);
+      return payload;
+    }
+
+    @Override
+    public void handleRequestFailure(SyncStorageResponse response) {
+      BaseResource.consumeEntity(response); // We don't need the response at all, and any exception handling shouldn't need the response body.
+      localAccountGUIDDownloaded = false;
+
+      try {
+        Logger.info(LOG_TAG, "Client upload failed. Aborting sync.");
+        session.abort(new HTTPFailureException(response), "Client download failed.");
+      } finally {
+        // Close the database upon failure.
+        closeDataAccessor();
+      }
+    }
+
+    @Override
+    public void handleRequestError(Exception ex) {
+      localAccountGUIDDownloaded = false;
+      try {
+        Logger.info(LOG_TAG, "Client upload error. Aborting sync.");
+        session.abort(ex, "Failure fetching client record.");
+      } finally {
+        // Close the database upon error.
+        closeDataAccessor();
+      }
+    }
+
+    @Override
+    public void handleWBO(CryptoRecord record) {
+      ClientRecord r;
+      try {
+        r = (ClientRecord) factory.createRecord(record.decrypt());
+        if (clientsDelegate.isLocalGUID(r.guid)) {
+          Logger.info(LOG_TAG, "Local client GUID exists on server and was downloaded.");
+          localAccountGUIDDownloaded = true;
+          handleDownloadedLocalRecord(r);
+        } else {
+          // Only need to store record if it isn't our local one.
+          wipeAndStore(r);
+          addCommands(r);
+        }
+        RepoUtils.logClient(r);
+      } catch (Exception e) {
+        session.abort(e, "Exception handling client WBO.");
+        return;
+      }
+    }
+
+    @Override
+    public KeyBundle keyBundle() {
+      try {
+        return session.keyBundleForCollection(COLLECTION_NAME);
+      } catch (NoCollectionKeysSetException e) {
+        return null;
+      }
+    }
+  }
+
+  public class ClientUploadDelegate extends WBORequestDelegate {
+    protected static final String LOG_TAG = "ClientUploadDelegate";
+    public Long currentlyUploadingRecordTimestamp;
+    public boolean currentlyUploadingLocalRecord;
+
+    @Override
+    public AuthHeaderProvider getAuthHeaderProvider() {
+      return session.getAuthHeaderProvider();
+    }
+
+    private void setUploadDetails(boolean isLocalRecord) {
+      // Use the timestamp for the whole collection per Sync storage 1.1 spec.
+      currentlyUploadingRecordTimestamp = session.config.getPersistedServerClientsTimestamp();
+      currentlyUploadingLocalRecord = isLocalRecord;
+    }
+
+    @Override
+    public String ifUnmodifiedSince() {
+      Long timestampInMilliseconds = currentlyUploadingRecordTimestamp;
+
+      // It's the first upload so we don't care about X-If-Unmodified-Since.
+      if (timestampInMilliseconds <= 0) {
+        return null;
+      }
+
+      return Utils.millisecondsToDecimalSecondsString(timestampInMilliseconds);
+    }
+
+    @Override
+    public void handleRequestSuccess(SyncStorageResponse response) {
+      Logger.debug(LOG_TAG, "Upload succeeded.");
+      uploadAttemptsCount.set(0);
+
+      // X-Weave-Timestamp is the modified time of uploaded records.
+      // Always persist this.
+      final long responseTimestamp = response.normalizedWeaveTimestamp();
+      Logger.trace(LOG_TAG, "Timestamp from header is: " + responseTimestamp);
+
+      if (responseTimestamp == -1) {
+        final String message = "Response did not contain a valid timestamp.";
+        session.abort(new RuntimeException(message), message);
+        return;
+      }
+
+      BaseResource.consumeEntity(response);
+      session.config.persistServerClientsTimestamp(responseTimestamp);
+
+      // If we're not uploading our record, we're done here; just
+      // clean up and finish.
+      if (!currentlyUploadingLocalRecord) {
+        // TODO: check failed uploads in body.
+        clearRecordsToUpload();
+        checkAndUpload();
+        return;
+      }
+
+      // If we're processing our record, we have a little more cleanup
+      // to do.
+      shouldUploadLocalRecord = false;
+      session.config.persistServerClientRecordTimestamp(responseTimestamp);
+      session.advance();
+    }
+
+    @Override
+    public void handleRequestFailure(SyncStorageResponse response) {
+      int statusCode = response.getStatusCode();
+
+      // If upload failed because of `ifUnmodifiedSince` then there are new
+      // commands uploaded to our record. We must download and process them first.
+      if (!shouldUploadLocalRecord ||
+          statusCode == HttpStatus.SC_PRECONDITION_FAILED ||
+          uploadAttemptsCount.incrementAndGet() > MAX_UPLOAD_FAILURE_COUNT) {
+
+        Logger.debug(LOG_TAG, "Client upload failed. Aborting sync.");
+        if (!currentlyUploadingLocalRecord) {
+          modifiedClientsToUpload.clear(); // These will be redownloaded.
+        }
+        BaseResource.consumeEntity(response); // The exception thrown should need the response body.
+        session.abort(new HTTPFailureException(response), "Client upload failed.");
+        return;
+      }
+      Logger.trace(LOG_TAG, "Retrying upload…");
+      // Preconditions:
+      // shouldUploadLocalRecord == true &&
+      // statusCode != 412 &&
+      // uploadAttemptCount < MAX_UPLOAD_FAILURE_COUNT
+      checkAndUpload();
+    }
+
+    @Override
+    public void handleRequestError(Exception ex) {
+      Logger.info(LOG_TAG, "Client upload error. Aborting sync.");
+      session.abort(ex, "Client upload failed.");
+    }
+
+    @Override
+    public KeyBundle keyBundle() {
+      try {
+        return session.keyBundleForCollection(COLLECTION_NAME);
+      } catch (NoCollectionKeysSetException e) {
+        return null;
+      }
+    }
+  }
+
+  @Override
+  public void execute() throws NoSuchStageException {
+    // We can be disabled just for this sync.
+    boolean enabledThisSync = session.isEngineLocallyEnabled(STAGE_NAME);
+    if (!enabledThisSync) {
+      // These log messages look best when they match the messages in ServerSyncStage.
+      Logger.debug(LOG_TAG, "Stage " + STAGE_NAME + " disabled just for this sync.");
+      Logger.info(LOG_TAG, "Skipping stage " + STAGE_NAME + ".");
+      session.advance();
+      return;
+    }
+
+    if (shouldDownload()) {
+      downloadClientRecords();   // Will kick off upload, too…
+    } else {
+      // Upload if necessary.
+    }
+  }
+
+  @Override
+  protected void resetLocal() {
+    // Clear timestamps and local data.
+    session.config.persistServerClientRecordTimestamp(0L);   // TODO: roll these into one.
+    session.config.persistServerClientsTimestamp(0L);
+
+    session.getClientsDelegate().setClientsCount(0);
+    try {
+      getClientsDatabaseAccessor().wipeDB();
+    } finally {
+      closeDataAccessor();
+    }
+  }
+
+  @Override
+  protected void wipeLocal() throws Exception {
+    // Nothing more to do.
+    this.resetLocal();
+  }
+
+  @Override
+  public Integer getStorageVersion() {
+    return VersionConstants.CLIENTS_ENGINE_VERSION;
+  }
+
+  protected String getLocalClientVersion() {
+    return AppConstants.MOZ_APP_VERSION;
+  }
+
+  @SuppressWarnings("unchecked")
+  protected JSONArray getLocalClientProtocols() {
+    final JSONArray protocols = new JSONArray();
+    protocols.add(ClientRecord.PROTOCOL_LEGACY_SYNC);
+    protocols.add(ClientRecord.PROTOCOL_FXA_SYNC);
+    return protocols;
+  }
+
+  protected ClientRecord newLocalClientRecord(ClientsDataDelegate delegate) {
+    final String ourGUID = delegate.getAccountGUID();
+    final String ourName = delegate.getClientName();
+
+    ClientRecord r = new ClientRecord(ourGUID);
+    r.name = ourName;
+    r.version = getLocalClientVersion();
+    r.protocols = getLocalClientProtocols();
+
+    r.os = "Android";
+    r.application = AppConstants.MOZ_APP_DISPLAYNAME;
+    r.appPackage = AppConstants.ANDROID_PACKAGE_NAME;
+    r.device = android.os.Build.MODEL;
+    r.formfactor = delegate.getFormFactor();
+
+    Context context = session.getContext();
+    final Account account = FirefoxAccounts.getFirefoxAccount(context);
+    if (account != null) {
+      final AndroidFxAccount fxAccount = new AndroidFxAccount(context, account);
+      final String deviceId = fxAccount.getDeviceId();
+      if (!TextUtils.isEmpty(deviceId)) {
+        r.fxaDeviceId = deviceId;
+      }
+    }
+
+    return r;
+  }
+
+  // TODO: Bug 726055 - More considered handling of when to sync.
+  protected boolean shouldDownload() {
+    // Ask info/collections whether a download is needed.
+    return true;
+  }
+
+  protected boolean shouldUpload() {
+    if (shouldUploadLocalRecord) {
+      return true;
+    }
+
+    long lastUpload = session.config.getPersistedServerClientRecordTimestamp();   // Defaults to 0.
+    if (lastUpload == 0) {
+      return true;
+    }
+
+    if (session.getClientsDelegate().getLastModifiedTimestamp() > lastUpload) {
+      // Something's changed locally since we last uploaded.
+      return true;
+    }
+
+    // Note the opportunity for clock drift problems here.
+    // TODO: if we track download times, we can use the timestamp of most
+    // recent download response instead of the current time.
+    long now = System.currentTimeMillis();
+    long age = now - lastUpload;
+    return age >= CLIENTS_TTL_REFRESH;
+  }
+
+  protected void handleDownloadedLocalRecord(ClientRecord r) {
+    session.config.persistServerClientRecordTimestamp(r.lastModified);
+
+    if (!getLocalClientVersion().equals(r.version) ||
+        !getLocalClientProtocols().equals(r.protocols)) {
+      shouldUploadLocalRecord = true;
+    }
+    processCommands(r.commands);
+  }
+
+  protected void processCommands(JSONArray commands) {
+    if (commands == null ||
+        commands.size() == 0) {
+      return;
+    }
+
+    shouldUploadLocalRecord = true;
+    CommandProcessor processor = CommandProcessor.getProcessor();
+
+    for (Object o : commands) {
+      processor.processCommand(session, new ExtendedJSONObject((JSONObject) o));
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  protected void addCommands(ClientRecord record) throws NullCursorException {
+    Logger.trace(LOG_TAG, "Adding commands to " + record.guid);
+    List<Command> commands = db.fetchCommandsForClient(record.guid);
+
+    if (commands == null || commands.size() == 0) {
+      Logger.trace(LOG_TAG, "No commands to add.");
+      return;
+    }
+
+    for (Command command : commands) {
+      JSONObject jsonCommand = command.asJSONObject();
+      if (record.commands == null) {
+        record.commands = new JSONArray();
+      }
+      record.commands.add(jsonCommand);
+    }
+    modifiedClientsToUpload.add(record);
+  }
+
+  @SuppressWarnings("unchecked")
+  protected void uploadRemoteRecords() {
+    Logger.trace(LOG_TAG, "In uploadRemoteRecords. Uploading " + modifiedClientsToUpload.size() + " records" );
+
+    for (ClientRecord r : modifiedClientsToUpload) {
+      Logger.trace(LOG_TAG, ">> Uploading record " + r.guid + ": " + r.name);
+    }
+
+    if (modifiedClientsToUpload.size() == 1) {
+      ClientRecord record = modifiedClientsToUpload.get(0);
+      Logger.debug(LOG_TAG, "Only 1 remote record to upload.");
+      Logger.debug(LOG_TAG, "Record last modified: " + record.lastModified);
+      CryptoRecord cryptoRecord = encryptClientRecord(record);
+      if (cryptoRecord != null) {
+        clientUploadDelegate.setUploadDetails(false);
+        this.uploadClientRecord(cryptoRecord);
+      }
+      return;
+    }
+
+    JSONArray cryptoRecords = new JSONArray();
+    for (ClientRecord record : modifiedClientsToUpload) {
+      Logger.trace(LOG_TAG, "Record " + record.guid + " is being uploaded" );
+
+      CryptoRecord cryptoRecord = encryptClientRecord(record);
+      cryptoRecords.add(cryptoRecord.toJSONObject());
+    }
+    Logger.debug(LOG_TAG, "Uploading records: " + cryptoRecords.size());
+    clientUploadDelegate.setUploadDetails(false);
+    this.uploadClientRecords(cryptoRecords);
+  }
+
+  protected void checkAndUpload() {
+    if (!shouldUpload()) {
+      Logger.debug(LOG_TAG, "Not uploading client record.");
+      session.advance();
+      return;
+    }
+
+    final ClientRecord localClient = newLocalClientRecord(session.getClientsDelegate());
+    clientUploadDelegate.setUploadDetails(true);
+    CryptoRecord cryptoRecord = encryptClientRecord(localClient);
+    if (cryptoRecord != null) {
+      this.uploadClientRecord(cryptoRecord);
+    }
+  }
+
+  protected CryptoRecord encryptClientRecord(ClientRecord recordToUpload) {
+    // Generate CryptoRecord from ClientRecord to upload.
+    final String encryptionFailure = "Couldn't encrypt new client record.";
+
+    try {
+      CryptoRecord cryptoRecord = recordToUpload.getEnvelope();
+      cryptoRecord.keyBundle = clientUploadDelegate.keyBundle();
+      if (cryptoRecord.keyBundle == null) {
+        session.abort(new NoCollectionKeysSetException(), "No collection keys set.");
+        return null;
+      }
+      return cryptoRecord.encrypt();
+    } catch (UnsupportedEncodingException e) {
+      session.abort(e, encryptionFailure + " Unsupported encoding.");
+    } catch (CryptoException e) {
+      session.abort(e, encryptionFailure);
+    }
+    return null;
+  }
+
+  public void clearRecordsToUpload() {
+    try {
+      getClientsDatabaseAccessor().wipeCommandsTable();
+      modifiedClientsToUpload.clear();
+    } finally {
+      closeDataAccessor();
+    }
+  }
+
+  protected void downloadClientRecords() {
+    shouldWipe = true;
+    clientDownloadDelegate = makeClientDownloadDelegate();
+
+    try {
+      final URI getURI = session.config.collectionURI(COLLECTION_NAME, true);
+      final SyncStorageCollectionRequest request = new SyncStorageCollectionRequest(getURI);
+      request.delegate = clientDownloadDelegate;
+
+      Logger.trace(LOG_TAG, "Downloading client records.");
+      request.get();
+    } catch (URISyntaxException e) {
+      session.abort(e, "Invalid URI.");
+    }
+  }
+
+  protected void uploadClientRecords(JSONArray records) {
+    Logger.trace(LOG_TAG, "Uploading " + records.size() + " client records.");
+    try {
+      final URI postURI = session.config.collectionURI(COLLECTION_NAME, false);
+      final SyncStorageRecordRequest request = new SyncStorageRecordRequest(postURI);
+      request.delegate = clientUploadDelegate;
+      request.post(records);
+    } catch (URISyntaxException e) {
+      session.abort(e, "Invalid URI.");
+    } catch (Exception e) {
+      session.abort(e, "Unable to parse body.");
+    }
+  }
+
+  /**
+   * Upload a client record via HTTP POST to the parent collection.
+   */
+  protected void uploadClientRecord(CryptoRecord record) {
+    Logger.debug(LOG_TAG, "Uploading client record " + record.guid);
+    try {
+      final URI postURI = session.config.collectionURI(COLLECTION_NAME);
+      final SyncStorageRecordRequest request = new SyncStorageRecordRequest(postURI);
+      request.delegate = clientUploadDelegate;
+      request.post(record);
+    } catch (URISyntaxException e) {
+      session.abort(e, "Invalid URI.");
+    }
+  }
+
+  protected ClientDownloadDelegate makeClientDownloadDelegate() {
+    return new ClientDownloadDelegate();
+  }
+
+  protected void wipeAndStore(ClientRecord record) {
+    final ClientsDatabaseAccessor db = getClientsDatabaseAccessor();
+    if (shouldWipe) {
+      db.wipeClientsTable();
+      shouldWipe = false;
+    }
+    if (record != null) {
+      db.store(record);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/UploadMetaGlobalStage.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/UploadMetaGlobalStage.java
new file mode 100644
index 000000000..77846c212
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/stage/UploadMetaGlobalStage.java
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.stage;
+
+
+public class UploadMetaGlobalStage extends AbstractNonRepositorySyncStage {
+  public static final String LOG_TAG = "UploadMGStage";
+
+  @Override
+  public void execute() throws NoSuchStageException {
+    if (session.hasUpdatedMetaGlobal()) {
+      session.uploadUpdatedMetaGlobal();
+    }
+    session.advance();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/ConcurrentRecordConsumer.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/ConcurrentRecordConsumer.java
new file mode 100644
index 000000000..9b1ef3e85
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/ConcurrentRecordConsumer.java
@@ -0,0 +1,122 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+/**
+ * Consume records from a queue inside a RecordsChannel, as fast as we can.
+ * TODO: rewrite this in terms of an ExecutorService and a CompletionService.
+ * See Bug 713483.
+ *
+ * @author rnewman
+ *
+ */
+class ConcurrentRecordConsumer extends RecordConsumer {
+  private static final String LOG_TAG = "CRecordConsumer";
+
+  /**
+   * When this is true and all records have been processed, the consumer
+   * will notify its delegate.
+   */
+  protected boolean allRecordsQueued = false;
+  private long counter = 0;
+
+  public ConcurrentRecordConsumer(RecordsConsumerDelegate delegate) {
+    this.delegate = delegate;
+  }
+
+  private final Object monitor = new Object();
+  @Override
+  public void doNotify() {
+    synchronized (monitor) {
+      monitor.notify();
+    }
+  }
+
+  @Override
+  public void queueFilled() {
+    Logger.debug(LOG_TAG, "Queue filled.");
+    synchronized (monitor) {
+      this.allRecordsQueued = true;
+      monitor.notify();
+    }
+  }
+
+  @Override
+  public void halt() {
+    synchronized (monitor) {
+      this.stopImmediately = true;
+      monitor.notify();
+    }
+  }
+
+  private final Object countMonitor = new Object();
+  @Override
+  public void stored() {
+    Logger.trace(LOG_TAG, "Record stored. Notifying.");
+    synchronized (countMonitor) {
+      counter++;
+    }
+  }
+
+  private void consumerIsDone() {
+    Logger.debug(LOG_TAG, "Consumer is done. Processed " + counter + ((counter == 1) ? " record." : " records."));
+    delegate.consumerIsDone(!allRecordsQueued);
+  }
+
+  @Override
+  public void run() {
+    Record record;
+
+    while (true) {
+      // The queue is concurrent-safe.
+      while ((record = delegate.getQueue().poll()) != null) {
+        synchronized (monitor) {
+          Logger.trace(LOG_TAG, "run() took monitor.");
+          if (stopImmediately) {
+            Logger.debug(LOG_TAG, "Stopping immediately. Clearing queue.");
+            delegate.getQueue().clear();
+            Logger.debug(LOG_TAG, "Notifying consumer.");
+            consumerIsDone();
+            return;
+          }
+          Logger.debug(LOG_TAG, "run() dropped monitor.");
+        }
+
+        Logger.trace(LOG_TAG, "Storing record with guid " + record.guid + ".");
+        try {
+          delegate.store(record);
+        } catch (Exception e) {
+          // TODO: Bug 709371: track records that failed to apply.
+          Logger.error(LOG_TAG, "Caught error in store.", e);
+        }
+        Logger.trace(LOG_TAG, "Done with record.");
+      }
+      synchronized (monitor) {
+        Logger.trace(LOG_TAG, "run() took monitor.");
+
+        if (allRecordsQueued) {
+          Logger.debug(LOG_TAG, "Done with records and no more to come. Notifying consumerIsDone.");
+          consumerIsDone();
+          return;
+        }
+        if (stopImmediately) {
+          Logger.debug(LOG_TAG, "Done with records and told to stop immediately. Notifying consumerIsDone.");
+          consumerIsDone();
+          return;
+        }
+        try {
+          Logger.debug(LOG_TAG, "Not told to stop but no records. Waiting.");
+          monitor.wait(10000);
+        } catch (InterruptedException e) {
+          // TODO
+        }
+        Logger.trace(LOG_TAG, "run() dropped monitor.");
+      }
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordConsumer.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordConsumer.java
new file mode 100644
index 000000000..35e57d9c2
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordConsumer.java
@@ -0,0 +1,26 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+public abstract class RecordConsumer implements Runnable {
+
+  public abstract void stored();
+
+  /**
+   * There are no more store items to arrive at the delegate.
+   * When you're done, take care of finishing up.
+   */
+  public abstract void queueFilled();
+  public abstract void halt();
+
+  public abstract void doNotify();
+
+  protected boolean stopImmediately = false;
+  protected RecordsConsumerDelegate delegate;
+
+  public RecordConsumer() {
+    super();
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannel.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannel.java
new file mode 100644
index 000000000..f929cdc75
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannel.java
@@ -0,0 +1,292 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ThreadPool;
+import org.mozilla.gecko.sync.repositories.InvalidSessionTransitionException;
+import org.mozilla.gecko.sync.repositories.NoStoreDelegateException;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+import org.mozilla.gecko.sync.repositories.delegates.DeferredRepositorySessionBeginDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.DeferredRepositorySessionStoreDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionBeginDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFetchRecordsDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionStoreDelegate;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+/**
+ * Pulls records from `source`, applying them to `sink`.
+ * Notifies its delegate of errors and completion.
+ *
+ * All stores (initiated by a fetch) must have been completed before storeDone
+ * is invoked on the sink. This is to avoid the existing stored items being
+ * considered as the total set, with onStoreCompleted being called when they're
+ * done:
+ *
+ *   store(A) store(B)
+ *   store(C) storeDone()
+ *   store(A) finishes. Store job begins.
+ *   store(C) finishes. Store job begins.
+ *   storeDone() finishes.
+ *   Storing of A complete.
+ *   Storing of C complete.
+ *   We're done! Call onStoreCompleted.
+ *   store(B) finishes... uh oh.
+ *
+ * In other words, storeDone must be gated on the synchronous invocation of every store.
+ *
+ * Similarly, we require that every store callback have returned before onStoreCompleted is invoked.
+ *
+ * This whole set of guarantees should be achievable thusly:
+ *
+ * * The fetch process must run in a single thread, and invoke store()
+ *   synchronously. After processing every incoming record, storeDone is called,
+ *   setting a flag.
+ *   If the fetch cannot be implicitly queued, it must be explicitly queued.
+ *   In this implementation, we assume that fetch callbacks are strictly ordered in this way.
+ *
+ * * The store process must be (implicitly or explicitly) queued. When the
+ *   queue empties, the consumer checks the storeDone flag. If it's set, and the
+ *   queue is exhausted, invoke onStoreCompleted.
+ *
+ * RecordsChannel exists to enforce this ordering of operations.
+ *
+ * @author rnewman
+ *
+ */
+public class RecordsChannel implements
+  RepositorySessionFetchRecordsDelegate,
+  RepositorySessionStoreDelegate,
+  RecordsConsumerDelegate,
+  RepositorySessionBeginDelegate {
+
+  private static final String LOG_TAG = "RecordsChannel";
+  public RepositorySession source;
+  public RepositorySession sink;
+  private final RecordsChannelDelegate delegate;
+  private long fetchEnd = -1;
+
+  protected final AtomicInteger numFetched = new AtomicInteger();
+  protected final AtomicInteger numFetchFailed = new AtomicInteger();
+  protected final AtomicInteger numStored = new AtomicInteger();
+  protected final AtomicInteger numStoreFailed = new AtomicInteger();
+
+  public RecordsChannel(RepositorySession source, RepositorySession sink, RecordsChannelDelegate delegate) {
+    this.source    = source;
+    this.sink      = sink;
+    this.delegate  = delegate;
+  }
+
+  /*
+   * We push fetched records into a queue.
+   * A separate thread is waiting for us to notify it of work to do.
+   * When we tell it to stop, it'll stop. We do that when the fetch
+   * is completed.
+   * When it stops, we tell the sink that there are no more records,
+   * and wait for the sink to tell us that storing is done.
+   * Then we notify our delegate of completion.
+   */
+  private RecordConsumer consumer;
+  private boolean waitingForQueueDone = false;
+  private final ConcurrentLinkedQueue<Record> toProcess = new ConcurrentLinkedQueue<Record>();
+
+  @Override
+  public ConcurrentLinkedQueue<Record> getQueue() {
+    return toProcess;
+  }
+
+  protected boolean isReady() {
+    return source.isActive() && sink.isActive();
+  }
+
+  /**
+   * Get the number of records fetched so far.
+   *
+   * @return number of fetches.
+   */
+  public int getFetchCount() {
+    return numFetched.get();
+  }
+
+  /**
+   * Get the number of fetch failures recorded so far.
+   *
+   * @return number of fetch failures.
+   */
+  public int getFetchFailureCount() {
+    return numFetchFailed.get();
+  }
+
+  /**
+   * Get the number of store attempts (successful or not) so far.
+   *
+   * @return number of stores attempted.
+   */
+  public int getStoreCount() {
+    return numStored.get();
+  }
+
+  /**
+   * Get the number of store failures recorded so far.
+   *
+   * @return number of store failures.
+   */
+  public int getStoreFailureCount() {
+    return numStoreFailed.get();
+  }
+
+  /**
+   * Start records flowing through the channel.
+   */
+  public void flow() {
+    if (!isReady()) {
+      RepositorySession failed = source;
+      if (source.isActive()) {
+        failed = sink;
+      }
+      this.delegate.onFlowBeginFailed(this, new SessionNotBegunException(failed));
+      return;
+    }
+
+    if (!source.dataAvailable()) {
+      Logger.info(LOG_TAG, "No data available: short-circuiting flow from source " + source);
+      long now = System.currentTimeMillis();
+      this.delegate.onFlowCompleted(this, now, now);
+      return;
+    }
+
+    sink.setStoreDelegate(this);
+    numFetched.set(0);
+    numFetchFailed.set(0);
+    numStored.set(0);
+    numStoreFailed.set(0);
+    // Start a consumer thread.
+    this.consumer = new ConcurrentRecordConsumer(this);
+    ThreadPool.run(this.consumer);
+    waitingForQueueDone = true;
+    source.fetchSince(source.getLastSyncTimestamp(), this);
+  }
+
+  /**
+   * Begin both sessions, invoking flow() when done.
+   * @throws InvalidSessionTransitionException
+   */
+  public void beginAndFlow() throws InvalidSessionTransitionException {
+    Logger.trace(LOG_TAG, "Beginning source.");
+    source.begin(this);
+  }
+
+  @Override
+  public void store(Record record) {
+    numStored.incrementAndGet();
+    try {
+      sink.store(record);
+    } catch (NoStoreDelegateException e) {
+      Logger.error(LOG_TAG, "Got NoStoreDelegateException in RecordsChannel.store(). This should not occur. Aborting.", e);
+      delegate.onFlowStoreFailed(this, e, record.guid);
+    }
+  }
+
+  @Override
+  public void onFetchFailed(Exception ex, Record record) {
+    Logger.warn(LOG_TAG, "onFetchFailed. Calling for immediate stop.", ex);
+    numFetchFailed.incrementAndGet();
+    this.consumer.halt();
+    delegate.onFlowFetchFailed(this, ex);
+  }
+
+  @Override
+  public void onFetchedRecord(Record record) {
+    numFetched.incrementAndGet();
+    this.toProcess.add(record);
+    this.consumer.doNotify();
+  }
+
+  @Override
+  public void onFetchCompleted(final long fetchEnd) {
+    Logger.trace(LOG_TAG, "onFetchCompleted. Stopping consumer once stores are done.");
+    Logger.trace(LOG_TAG, "Fetch timestamp is " + fetchEnd);
+    this.fetchEnd = fetchEnd;
+    this.consumer.queueFilled();
+  }
+
+  @Override
+  public void onRecordStoreFailed(Exception ex, String recordGuid) {
+    Logger.trace(LOG_TAG, "Failed to store record with guid " + recordGuid);
+    numStoreFailed.incrementAndGet();
+    this.consumer.stored();
+    delegate.onFlowStoreFailed(this, ex, recordGuid);
+    // TODO: abort?
+  }
+
+  @Override
+  public void onRecordStoreSucceeded(String guid) {
+    Logger.trace(LOG_TAG, "Stored record with guid " + guid);
+    this.consumer.stored();
+  }
+
+
+  @Override
+  public void consumerIsDone(boolean allRecordsQueued) {
+    Logger.trace(LOG_TAG, "Consumer is done. Are we waiting for it? " + waitingForQueueDone);
+    if (waitingForQueueDone) {
+      waitingForQueueDone = false;
+      this.sink.storeDone();                 // Now we'll be waiting for onStoreCompleted.
+    }
+  }
+
+  @Override
+  public void onStoreCompleted(long storeEnd) {
+    Logger.trace(LOG_TAG, "onStoreCompleted. Notifying delegate of onFlowCompleted. " +
+                          "Fetch end is " + fetchEnd + ", store end is " + storeEnd);
+    // TODO: synchronize on consumer callback?
+    delegate.onFlowCompleted(this, fetchEnd, storeEnd);
+  }
+
+  @Override
+  public void onBeginFailed(Exception ex) {
+    delegate.onFlowBeginFailed(this, ex);
+  }
+
+  @Override
+  public void onBeginSucceeded(RepositorySession session) {
+    if (session == source) {
+      Logger.trace(LOG_TAG, "Source session began. Beginning sink session.");
+      try {
+        sink.begin(this);
+      } catch (InvalidSessionTransitionException e) {
+        onBeginFailed(e);
+        return;
+      }
+    }
+    if (session == sink) {
+      Logger.trace(LOG_TAG, "Sink session began. Beginning flow.");
+      this.flow();
+      return;
+    }
+
+    // TODO: error!
+  }
+
+  @Override
+  public RepositorySessionStoreDelegate deferredStoreDelegate(final ExecutorService executor) {
+    return new DeferredRepositorySessionStoreDelegate(this, executor);
+  }
+
+  @Override
+  public RepositorySessionBeginDelegate deferredBeginDelegate(final ExecutorService executor) {
+    return new DeferredRepositorySessionBeginDelegate(this, executor);
+  }
+
+  @Override
+  public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor) {
+    // Lie outright. We know that all of our fetch methods are safe.
+    return this;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannelDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannelDelegate.java
new file mode 100644
index 000000000..8daeb7ad5
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannelDelegate.java
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+public interface RecordsChannelDelegate {
+  public void onFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd);
+  public void onFlowBeginFailed(RecordsChannel recordsChannel, Exception ex);
+  public void onFlowFetchFailed(RecordsChannel recordsChannel, Exception ex);
+  public void onFlowStoreFailed(RecordsChannel recordsChannel, Exception ex, String recordGuid);
+  public void onFlowFinishFailed(RecordsChannel recordsChannel, Exception ex);
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsConsumerDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsConsumerDelegate.java
new file mode 100644
index 000000000..a00abf848
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsConsumerDelegate.java
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+import java.util.concurrent.ConcurrentLinkedQueue;
+
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+interface RecordsConsumerDelegate {
+  public abstract ConcurrentLinkedQueue<Record> getQueue();
+
+  /**
+   * Called when no more items will be processed.
+   * If forced is true, the consumer is terminating because it was told to halt;
+   * not all items will necessarily have been processed.
+   * If forced is false, the consumer has invoked store and received an onStoreCompleted callback.
+   * @param forced
+   */
+  public abstract void consumerIsDone(boolean forced);
+  public abstract void store(Record record);
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SerialRecordConsumer.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SerialRecordConsumer.java
new file mode 100644
index 000000000..6ee44ea2b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SerialRecordConsumer.java
@@ -0,0 +1,131 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.domain.Record;
+
+/**
+ * Consume records from a queue inside a RecordsChannel, storing them serially.
+ * @author rnewman
+ *
+ */
+class SerialRecordConsumer extends RecordConsumer {
+  private static final String LOG_TAG = "SerialRecordConsumer";
+  protected boolean stopEventually = false;
+  private volatile long counter = 0;
+
+  public SerialRecordConsumer(RecordsConsumerDelegate delegate) {
+    this.delegate = delegate;
+  }
+
+  private final Object monitor = new Object();
+  @Override
+  public void doNotify() {
+    synchronized (monitor) {
+      monitor.notify();
+    }
+  }
+
+  @Override
+  public void queueFilled() {
+    Logger.debug(LOG_TAG, "Queue filled.");
+    synchronized (monitor) {
+      this.stopEventually = true;
+      monitor.notify();
+    }
+  }
+
+  @Override
+  public void halt() {
+    Logger.debug(LOG_TAG, "Halting.");
+    synchronized (monitor) {
+      this.stopEventually = true;
+      this.stopImmediately = true;
+      monitor.notify();
+    }
+  }
+
+  private final Object storeSerializer = new Object();
+  @Override
+  public void stored() {
+    Logger.debug(LOG_TAG, "Record stored. Notifying.");
+    synchronized (storeSerializer) {
+      Logger.debug(LOG_TAG, "stored() took storeSerializer.");
+      counter++;
+      storeSerializer.notify();
+      Logger.debug(LOG_TAG, "stored() dropped storeSerializer.");
+    }
+  }
+  private void storeSerially(Record record) {
+    Logger.debug(LOG_TAG, "New record to store.");
+    synchronized (storeSerializer) {
+      Logger.debug(LOG_TAG, "storeSerially() took storeSerializer.");
+      Logger.debug(LOG_TAG, "Storing...");
+      try {
+        this.delegate.store(record);
+      } catch (Exception e) {
+        Logger.warn(LOG_TAG, "Got exception in store. Not waiting.", e);
+        return;      // So we don't block for a stored() that never comes.
+      }
+      try {
+        Logger.debug(LOG_TAG, "Waiting...");
+        storeSerializer.wait();
+      } catch (InterruptedException e) {
+        // TODO
+      }
+      Logger.debug(LOG_TAG, "storeSerially() dropped storeSerializer.");
+    }
+  }
+
+  private void consumerIsDone() {
+    long counterNow = this.counter;
+    Logger.info(LOG_TAG, "Consumer is done. Processed " + counterNow + ((counterNow == 1) ? " record." : " records."));
+    delegate.consumerIsDone(stopImmediately);
+  }
+
+  @Override
+  public void run() {
+    while (true) {
+      synchronized (monitor) {
+        Logger.debug(LOG_TAG, "run() took monitor.");
+        if (stopImmediately) {
+          Logger.debug(LOG_TAG, "Stopping immediately. Clearing queue.");
+          delegate.getQueue().clear();
+          Logger.debug(LOG_TAG, "Notifying consumer.");
+          consumerIsDone();
+          return;
+        }
+        Logger.debug(LOG_TAG, "run() dropped monitor.");
+      }
+      // The queue is concurrent-safe.
+      while (!delegate.getQueue().isEmpty()) {
+        Logger.debug(LOG_TAG, "Grabbing record...");
+        Record record = delegate.getQueue().remove();
+        // Block here, allowing us to process records
+        // serially.
+        Logger.debug(LOG_TAG, "Invoking storeSerially...");
+        this.storeSerially(record);
+        Logger.debug(LOG_TAG, "Done with record.");
+      }
+      synchronized (monitor) {
+        Logger.debug(LOG_TAG, "run() took monitor.");
+
+        if (stopEventually) {
+          Logger.debug(LOG_TAG, "Done with records and told to stop. Notifying consumer.");
+          consumerIsDone();
+          return;
+        }
+        try {
+          Logger.debug(LOG_TAG, "Not told to stop but no records. Waiting.");
+          monitor.wait(10000);
+        } catch (InterruptedException e) {
+          // TODO
+        }
+        Logger.debug(LOG_TAG, "run() dropped monitor.");
+      }
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/ServerLocalSynchronizer.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/ServerLocalSynchronizer.java
new file mode 100644
index 000000000..ac4f48789
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/ServerLocalSynchronizer.java
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+/**
+ * A <code>SynchronizerSession</code> designed to be used between a remote
+ * server and a local repository.
+ * <p>
+ * See <code>ServerLocalSynchronizerSession</code> for error handling details.
+ */
+public class ServerLocalSynchronizer extends Synchronizer {
+  @Override
+  public SynchronizerSession newSynchronizerSession() {
+    return new ServerLocalSynchronizerSession(this, this);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/ServerLocalSynchronizerSession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/ServerLocalSynchronizerSession.java
new file mode 100644
index 000000000..dc9eb01a0
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/ServerLocalSynchronizerSession.java
@@ -0,0 +1,78 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.FetchFailedException;
+import org.mozilla.gecko.sync.repositories.StoreFailedException;
+
+/**
+ * A <code>SynchronizerSession</code> designed to be used between a remote
+ * server and a local repository.
+ * <p>
+ * Handles failure cases as follows (in the order they will occur during a sync):
+ * <ul>
+ * <li>Remote fetch failures abort.</li>
+ * <li>Local store failures are ignored.</li>
+ * <li>Local fetch failures abort.</li>
+ * <li>Remote store failures abort.</li>
+ * </ul>
+ */
+public class ServerLocalSynchronizerSession extends SynchronizerSession {
+  protected static final String LOG_TAG = "ServLocSynchronizerSess";
+
+  public ServerLocalSynchronizerSession(Synchronizer synchronizer, SynchronizerSessionDelegate delegate) {
+    super(synchronizer, delegate);
+  }
+
+  @Override
+  public void onFirstFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
+    // Fetch failures always abort.
+    int numRemoteFetchFailed = recordsChannel.getFetchFailureCount();
+    if (numRemoteFetchFailed > 0) {
+      final String message = "Got " + numRemoteFetchFailed + " failures fetching remote records!";
+      Logger.warn(LOG_TAG, message + " Aborting session.");
+      delegate.onSynchronizeFailed(this, new FetchFailedException(), message);
+      return;
+    }
+    Logger.trace(LOG_TAG, "No failures fetching remote records.");
+
+    // Local store failures are ignored.
+    int numLocalStoreFailed = recordsChannel.getStoreFailureCount();
+    if (numLocalStoreFailed > 0) {
+      final String message = "Got " + numLocalStoreFailed + " failures storing local records!";
+      Logger.warn(LOG_TAG, message + " Ignoring local store failures and continuing synchronizer session.");
+    } else {
+      Logger.trace(LOG_TAG, "No failures storing local records.");
+    }
+
+    super.onFirstFlowCompleted(recordsChannel, fetchEnd, storeEnd);
+  }
+
+  @Override
+  public void onSecondFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
+    // Fetch failures always abort.
+    int numLocalFetchFailed = recordsChannel.getFetchFailureCount();
+    if (numLocalFetchFailed > 0) {
+      final String message = "Got " + numLocalFetchFailed + " failures fetching local records!";
+      Logger.warn(LOG_TAG, message + " Aborting session.");
+      delegate.onSynchronizeFailed(this, new FetchFailedException(), message);
+      return;
+    }
+    Logger.trace(LOG_TAG, "No failures fetching local records.");
+
+    // Remote store failures abort!
+    int numRemoteStoreFailed = recordsChannel.getStoreFailureCount();
+    if (numRemoteStoreFailed > 0) {
+      final String message = "Got " + numRemoteStoreFailed + " failures storing remote records!";
+      Logger.warn(LOG_TAG, message + " Aborting session.");
+      delegate.onSynchronizeFailed(this, new StoreFailedException(), message);
+      return;
+    }
+    Logger.trace(LOG_TAG, "No failures storing remote records.");
+
+    super.onSecondFlowCompleted(recordsChannel, fetchEnd, storeEnd);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SessionNotBegunException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SessionNotBegunException.java
new file mode 100644
index 000000000..20c7fcd56
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SessionNotBegunException.java
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+import org.mozilla.gecko.sync.SyncException;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+
+public class SessionNotBegunException extends SyncException {
+  
+  public RepositorySession failed;
+
+  public SessionNotBegunException(RepositorySession failed) {
+    this.failed = failed;
+  }
+
+  private static final long serialVersionUID = -4565241449897072841L;
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/Synchronizer.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/Synchronizer.java
new file mode 100644
index 000000000..cc15b35a9
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/Synchronizer.java
@@ -0,0 +1,105 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.SynchronizerConfiguration;
+import org.mozilla.gecko.sync.repositories.Repository;
+import org.mozilla.gecko.sync.repositories.RepositorySessionBundle;
+
+import android.content.Context;
+
+/**
+ * I perform a sync.
+ *
+ * Initialize me by calling `load` with a SynchronizerConfiguration.
+ *
+ * Start synchronizing by calling `synchronize` with a SynchronizerDelegate. I
+ * provide coarse-grained feedback by calling my delegate's callback methods.
+ *
+ * I always call exactly one of my delegate's `onSynchronized` or
+ * `onSynchronizeFailed` callback methods. In addition, I call
+ * `onSynchronizeAborted` before `onSynchronizeFailed` when I encounter a fetch,
+ * store, or session error while synchronizing.
+ *
+ * After synchronizing, call `save` to get back a SynchronizerConfiguration with
+ * updated bundle information.
+ */
+public class Synchronizer implements SynchronizerSessionDelegate {
+  public static final String LOG_TAG = "SyncDelSDelegate";
+
+  protected String configSyncID; // Used to pass syncID from load() back into save().
+
+  protected SynchronizerDelegate synchronizerDelegate;
+
+  protected SynchronizerSession session = null;
+
+  public SynchronizerSession getSynchronizerSession() {
+    return session;
+  }
+
+  @Override
+  public void onInitialized(SynchronizerSession session) {
+    session.synchronize();
+  }
+
+  @Override
+  public void onSynchronized(SynchronizerSession synchronizerSession) {
+    Logger.debug(LOG_TAG, "Got onSynchronized.");
+    Logger.debug(LOG_TAG, "Notifying SynchronizerDelegate.");
+    this.synchronizerDelegate.onSynchronized(synchronizerSession.getSynchronizer());
+  }
+
+  @Override
+  public void onSynchronizeSkipped(SynchronizerSession synchronizerSession) {
+    Logger.debug(LOG_TAG, "Got onSynchronizeSkipped.");
+    Logger.debug(LOG_TAG, "Notifying SynchronizerDelegate as if on success.");
+    this.synchronizerDelegate.onSynchronized(synchronizerSession.getSynchronizer());
+  }
+
+  @Override
+  public void onSynchronizeFailed(SynchronizerSession session,
+      Exception lastException, String reason) {
+    this.synchronizerDelegate.onSynchronizeFailed(session.getSynchronizer(), lastException, reason);
+  }
+
+  public Repository repositoryA;
+  public Repository repositoryB;
+  public RepositorySessionBundle bundleA;
+  public RepositorySessionBundle bundleB;
+
+  /**
+   * Fetch a synchronizer session appropriate for this <code>Synchronizer</code>
+   */
+  protected SynchronizerSession newSynchronizerSession() {
+    return new SynchronizerSession(this, this);
+  }
+
+  /**
+   * Start synchronizing, calling delegate's callback methods.
+   */
+  public void synchronize(Context context, SynchronizerDelegate delegate) {
+    this.synchronizerDelegate = delegate;
+    this.session = newSynchronizerSession();
+    this.session.init(context, bundleA, bundleB);
+  }
+
+  public SynchronizerConfiguration save() {
+    return new SynchronizerConfiguration(configSyncID, bundleA, bundleB);
+  }
+
+  /**
+   * Set my repository session bundles from a SynchronizerConfiguration.
+   *
+   * This method is not thread-safe.
+   *
+   * @param config
+   */
+  public void load(SynchronizerConfiguration config) {
+    bundleA = config.remoteBundle;
+    bundleB = config.localBundle;
+    configSyncID  = config.syncID;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SynchronizerDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SynchronizerDelegate.java
new file mode 100644
index 000000000..a290188ab
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SynchronizerDelegate.java
@@ -0,0 +1,10 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+public interface SynchronizerDelegate {
+  public void onSynchronized(Synchronizer synchronizer);
+  public void onSynchronizeFailed(Synchronizer synchronizer, Exception lastException, String reason);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SynchronizerSession.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SynchronizerSession.java
new file mode 100644
index 000000000..c4d244b4c
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SynchronizerSession.java
@@ -0,0 +1,425 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.repositories.InactiveSessionException;
+import org.mozilla.gecko.sync.repositories.InvalidSessionTransitionException;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+import org.mozilla.gecko.sync.repositories.RepositorySessionBundle;
+import org.mozilla.gecko.sync.repositories.delegates.DeferrableRepositorySessionCreationDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.DeferredRepositorySessionFinishDelegate;
+import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
+
+import android.content.Context;
+
+/**
+ * I coordinate the moving parts of a sync started by
+ * {@link Synchronizer#synchronize}.
+ *
+ * I flow records twice: first from A to B, and then from B to A. I provide
+ * fine-grained feedback by calling my delegate's callback methods.
+ *
+ * Initialize me by creating me with a Synchronizer and a
+ * SynchronizerSessionDelegate. Kick things off by calling `init` with two
+ * RepositorySessionBundles, and then call `synchronize` in your `onInitialized`
+ * callback.
+ *
+ * I always call exactly one of my delegate's `onInitialized` or
+ * `onSessionError` callback methods from `init`.
+ *
+ * I call my delegate's `onSynchronizeSkipped` callback method if there is no
+ * data to be synchronized in `synchronize`.
+ *
+ * In addition, I call `onFetchError`, `onStoreError`, and `onSessionError` when
+ * I encounter a fetch, store, or session error while synchronizing.
+ *
+ * Typically my delegate will call `abort` in its error callbacks, which will
+ * call my delegate's `onSynchronizeAborted` method and halt the sync.
+ *
+ * I always call exactly one of my delegate's `onSynchronized` or
+ * `onSynchronizeFailed` callback methods if I have not seen an error.
+ */
+public class SynchronizerSession
+extends DeferrableRepositorySessionCreationDelegate
+implements RecordsChannelDelegate,
+           RepositorySessionFinishDelegate {
+
+  protected static final String LOG_TAG = "SynchronizerSession";
+  protected Synchronizer synchronizer;
+  protected SynchronizerSessionDelegate delegate;
+  protected Context context;
+
+  /*
+   * Computed during init.
+   */
+  private RepositorySession sessionA;
+  private RepositorySession sessionB;
+  private RepositorySessionBundle bundleA;
+  private RepositorySessionBundle bundleB;
+
+  // Bug 726054: just like desktop, we track our last interaction with the server,
+  // not the last record timestamp that we fetched. This ensures that we don't re-
+  // download the records we just uploaded, at the cost of skipping any records
+  // that a concurrently syncing client has uploaded.
+  private long pendingATimestamp = -1;
+  private long pendingBTimestamp = -1;
+  private long storeEndATimestamp = -1;
+  private long storeEndBTimestamp = -1;
+  private boolean flowAToBCompleted = false;
+  private boolean flowBToACompleted = false;
+
+  protected final AtomicInteger numInboundRecords = new AtomicInteger(-1);
+  protected final AtomicInteger numOutboundRecords = new AtomicInteger(-1);
+
+  /*
+   * Public API: constructor, init, synchronize.
+   */
+  public SynchronizerSession(Synchronizer synchronizer, SynchronizerSessionDelegate delegate) {
+    this.setSynchronizer(synchronizer);
+    this.delegate = delegate;
+  }
+
+  public Synchronizer getSynchronizer() {
+    return synchronizer;
+  }
+
+  public void setSynchronizer(Synchronizer synchronizer) {
+    this.synchronizer = synchronizer;
+  }
+
+  public void init(Context context, RepositorySessionBundle bundleA, RepositorySessionBundle bundleB) {
+    this.context = context;
+    this.bundleA = bundleA;
+    this.bundleB = bundleB;
+    // Begin sessionA and sessionB, call onInitialized in callbacks.
+    this.getSynchronizer().repositoryA.createSession(this, context);
+  }
+
+  /**
+   * Get the number of records fetched from the first repository (usually the
+   * server, hence inbound).
+   * <p>
+   * Valid only after first flow has completed.
+   *
+   * @return number of records, or -1 if not valid.
+   */
+  public int getInboundCount() {
+    return numInboundRecords.get();
+  }
+
+  /**
+   * Get the number of records fetched from the second repository (usually the
+   * local store, hence outbound).
+   * <p>
+   * Valid only after second flow has completed.
+   *
+   * @return number of records, or -1 if not valid.
+   */
+  public int getOutboundCount() {
+    return numOutboundRecords.get();
+  }
+
+  // These are accessed by `abort` and `synchronize`, both of which are synchronized.
+  // Guarded by `this`.
+  protected RecordsChannel channelAToB;
+  protected RecordsChannel channelBToA;
+
+  /**
+   * Please don't call this until you've been notified with onInitialized.
+   */
+  public synchronized void synchronize() {
+    numInboundRecords.set(-1);
+    numOutboundRecords.set(-1);
+
+    // First thing: decide whether we should.
+    if (sessionA.shouldSkip() ||
+        sessionB.shouldSkip()) {
+      Logger.info(LOG_TAG, "Session requested skip. Short-circuiting sync.");
+      sessionA.abort();
+      sessionB.abort();
+      this.delegate.onSynchronizeSkipped(this);
+      return;
+    }
+
+    final SynchronizerSession session = this;
+
+    // TODO: failed record handling.
+
+    // This is the *second* record channel to flow.
+    // I, SynchronizerSession, am the delegate for the *second* flow.
+    channelBToA = new RecordsChannel(this.sessionB, this.sessionA, this);
+
+    // This is the delegate for the *first* flow.
+    RecordsChannelDelegate channelAToBDelegate = new RecordsChannelDelegate() {
+      @Override
+      public void onFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
+        session.onFirstFlowCompleted(recordsChannel, fetchEnd, storeEnd);
+      }
+
+      @Override
+      public void onFlowBeginFailed(RecordsChannel recordsChannel, Exception ex) {
+        Logger.warn(LOG_TAG, "First RecordsChannel onFlowBeginFailed. Logging session error.", ex);
+        session.delegate.onSynchronizeFailed(session, ex, "Failed to begin first flow.");
+      }
+
+      @Override
+      public void onFlowFetchFailed(RecordsChannel recordsChannel, Exception ex) {
+        Logger.warn(LOG_TAG, "First RecordsChannel onFlowFetchFailed. Logging remote fetch error.", ex);
+      }
+
+      @Override
+      public void onFlowStoreFailed(RecordsChannel recordsChannel, Exception ex, String recordGuid) {
+        Logger.warn(LOG_TAG, "First RecordsChannel onFlowStoreFailed. Logging local store error.", ex);
+      }
+
+      @Override
+      public void onFlowFinishFailed(RecordsChannel recordsChannel, Exception ex) {
+        Logger.warn(LOG_TAG, "First RecordsChannel onFlowFinishedFailed. Logging session error.", ex);
+        session.delegate.onSynchronizeFailed(session, ex, "Failed to finish first flow.");
+      }
+    };
+
+    // This is the *first* channel to flow.
+    channelAToB = new RecordsChannel(this.sessionA, this.sessionB, channelAToBDelegate);
+
+    Logger.trace(LOG_TAG, "Starting A to B flow. Channel is " + channelAToB);
+    try {
+      channelAToB.beginAndFlow();
+    } catch (InvalidSessionTransitionException e) {
+      onFlowBeginFailed(channelAToB, e);
+    }
+  }
+
+  /**
+   * Called after the first flow completes.
+   * <p>
+   * By default, any fetch and store failures are ignored.
+   * @param recordsChannel the <code>RecordsChannel</code> (for error testing).
+   * @param fetchEnd timestamp when fetches completed.
+   * @param storeEnd timestamp when stores completed.
+   */
+  public void onFirstFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
+    Logger.trace(LOG_TAG, "First RecordsChannel onFlowCompleted.");
+    Logger.debug(LOG_TAG, "Fetch end is " + fetchEnd + ". Store end is " + storeEnd + ". Starting next.");
+    pendingATimestamp = fetchEnd;
+    storeEndBTimestamp = storeEnd;
+    numInboundRecords.set(recordsChannel.getFetchCount());
+    flowAToBCompleted = true;
+    channelBToA.flow();
+  }
+
+  /**
+   * Called after the second flow completes.
+   * <p>
+   * By default, any fetch and store failures are ignored.
+   * @param recordsChannel the <code>RecordsChannel</code> (for error testing).
+   * @param fetchEnd timestamp when fetches completed.
+   * @param storeEnd timestamp when stores completed.
+   */
+  public void onSecondFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
+    Logger.trace(LOG_TAG, "Second RecordsChannel onFlowCompleted.");
+    Logger.debug(LOG_TAG, "Fetch end is " + fetchEnd + ". Store end is " + storeEnd + ". Finishing.");
+
+    pendingBTimestamp = fetchEnd;
+    storeEndATimestamp = storeEnd;
+    numOutboundRecords.set(recordsChannel.getFetchCount());
+    flowBToACompleted = true;
+
+    // Finish the two sessions.
+    try {
+      this.sessionA.finish(this);
+    } catch (InactiveSessionException e) {
+      this.onFinishFailed(e);
+      return;
+    }
+  }
+
+  @Override
+  public void onFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
+    onSecondFlowCompleted(recordsChannel, fetchEnd, storeEnd);
+  }
+
+  @Override
+  public void onFlowBeginFailed(RecordsChannel recordsChannel, Exception ex) {
+    Logger.warn(LOG_TAG, "Second RecordsChannel onFlowBeginFailed. Logging session error.", ex);
+    this.delegate.onSynchronizeFailed(this, ex, "Failed to begin second flow.");
+  }
+
+  @Override
+  public void onFlowFetchFailed(RecordsChannel recordsChannel, Exception ex) {
+    Logger.warn(LOG_TAG, "Second RecordsChannel onFlowFetchFailed. Logging local fetch error.", ex);
+  }
+
+  @Override
+  public void onFlowStoreFailed(RecordsChannel recordsChannel, Exception ex, String recordGuid) {
+    Logger.warn(LOG_TAG, "Second RecordsChannel onFlowStoreFailed. Logging remote store error.", ex);
+  }
+
+  @Override
+  public void onFlowFinishFailed(RecordsChannel recordsChannel, Exception ex) {
+    Logger.warn(LOG_TAG, "Second RecordsChannel onFlowFinishedFailed. Logging session error.", ex);
+    this.delegate.onSynchronizeFailed(this, ex, "Failed to finish second flow.");
+  }
+
+  /*
+   * RepositorySessionCreationDelegate methods.
+   */
+
+  /**
+   * I could be called twice: once for sessionA and once for sessionB.
+   *
+   * I try to clean up sessionA if it is not null, since the creation of
+   * sessionB must have failed.
+   */
+  @Override
+  public void onSessionCreateFailed(Exception ex) {
+    // Attempt to finish the first session, if the second is the one that failed.
+    if (this.sessionA != null) {
+      try {
+        // We no longer need a reference to our context.
+        this.context = null;
+        this.sessionA.finish(this);
+      } catch (Exception e) {
+        // Never mind; best-effort finish.
+      }
+    }
+    // We no longer need a reference to our context.
+    this.context = null;
+    this.delegate.onSynchronizeFailed(this, ex, "Failed to create session");
+  }
+
+  /**
+   * I should be called twice: first for sessionA and second for sessionB.
+   *
+   * If I am called for sessionB, I call my delegate's `onInitialized` callback
+   * method because my repository sessions are correctly initialized.
+   */
+  // TODO: some of this "finish and clean up" code can be refactored out.
+  @Override
+  public void onSessionCreated(RepositorySession session) {
+    if (session == null ||
+        this.sessionA == session) {
+      // TODO: clean up sessionA.
+      this.delegate.onSynchronizeFailed(this, new UnexpectedSessionException(session), "Failed to create session.");
+      return;
+    }
+    if (this.sessionA == null) {
+      this.sessionA = session;
+
+      // Unbundle.
+      try {
+        this.sessionA.unbundle(this.bundleA);
+      } catch (Exception e) {
+        this.delegate.onSynchronizeFailed(this, new UnbundleError(e, sessionA), "Failed to unbundle first session.");
+        // TODO: abort
+        return;
+      }
+      this.getSynchronizer().repositoryB.createSession(this, this.context);
+      return;
+    }
+    if (this.sessionB == null) {
+      this.sessionB = session;
+      // We no longer need a reference to our context.
+      this.context = null;
+
+      // Unbundle. We unbundled sessionA when that session was created.
+      try {
+        this.sessionB.unbundle(this.bundleB);
+      } catch (Exception e) {
+        this.delegate.onSynchronizeFailed(this, new UnbundleError(e, sessionA), "Failed to unbundle second session.");
+        return;
+      }
+
+      this.delegate.onInitialized(this);
+      return;
+    }
+    // TODO: need a way to make sure we don't call any more delegate methods.
+    this.delegate.onSynchronizeFailed(this, new UnexpectedSessionException(session), "Failed to create session.");
+  }
+
+  /*
+   * RepositorySessionFinishDelegate methods.
+   */
+
+  /**
+   * I could be called twice: once for sessionA and once for sessionB.
+   *
+   * If sessionB couldn't be created, I don't fail again.
+   */
+  @Override
+  public void onFinishFailed(Exception ex) {
+    if (this.sessionB == null) {
+      // Ah, it was a problem cleaning up. Never mind.
+      Logger.warn(LOG_TAG, "Got exception cleaning up first after second session creation failed.", ex);
+      return;
+    }
+    String session = (this.sessionA == null) ? "B" : "A";
+    this.delegate.onSynchronizeFailed(this, ex, "Finish of session " + session + " failed.");
+  }
+
+  /**
+   * I should be called twice: first for sessionA and second for sessionB.
+   *
+   * If I am called for sessionA, I try to finish sessionB.
+   *
+   * If I am called for sessionB, I call my delegate's `onSynchronized` callback
+   * method because my flows should have completed.
+   */
+  @Override
+  public void onFinishSucceeded(RepositorySession session,
+                                RepositorySessionBundle bundle) {
+    Logger.debug(LOG_TAG, "onFinishSucceeded. Flows? " + flowAToBCompleted + ", " + flowBToACompleted);
+
+    if (session == sessionA) {
+      if (flowAToBCompleted) {
+        Logger.debug(LOG_TAG, "onFinishSucceeded: bumping session A's timestamp to " + pendingATimestamp + " or " + storeEndATimestamp);
+        bundle.bumpTimestamp(Math.max(pendingATimestamp, storeEndATimestamp));
+        this.synchronizer.bundleA = bundle;
+      } else {
+        // Should not happen!
+        this.delegate.onSynchronizeFailed(this, new UnexpectedSessionException(sessionA), "Failed to finish first session.");
+        return;
+      }
+      if (this.sessionB != null) {
+        Logger.trace(LOG_TAG, "Finishing session B.");
+        // On to the next.
+        try {
+          this.sessionB.finish(this);
+        } catch (InactiveSessionException e) {
+          this.onFinishFailed(e);
+          return;
+        }
+      }
+    } else if (session == sessionB) {
+      if (flowBToACompleted) {
+        Logger.debug(LOG_TAG, "onFinishSucceeded: bumping session B's timestamp to " + pendingBTimestamp + " or " + storeEndBTimestamp);
+        bundle.bumpTimestamp(Math.max(pendingBTimestamp, storeEndBTimestamp));
+        this.synchronizer.bundleB = bundle;
+        Logger.trace(LOG_TAG, "Notifying delegate.onSynchronized.");
+        this.delegate.onSynchronized(this);
+      } else {
+        // Should not happen!
+        this.delegate.onSynchronizeFailed(this, new UnexpectedSessionException(sessionB), "Failed to finish second session.");
+        return;
+      }
+    } else {
+      // TODO: hurrrrrr...
+    }
+
+    if (this.sessionB == null) {
+      this.sessionA = null; // We're done.
+    }
+  }
+
+  @Override
+  public RepositorySessionFinishDelegate deferredFinishDelegate(final ExecutorService executor) {
+    return new DeferredRepositorySessionFinishDelegate(this, executor);
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SynchronizerSessionDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SynchronizerSessionDelegate.java
new file mode 100644
index 000000000..1d55274e8
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/SynchronizerSessionDelegate.java
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+public interface SynchronizerSessionDelegate {
+  public void onInitialized(SynchronizerSession session);
+
+  public void onSynchronized(SynchronizerSession session);
+  public void onSynchronizeFailed(SynchronizerSession session, Exception lastException, String reason);
+  public void onSynchronizeSkipped(SynchronizerSession synchronizerSession);
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/UnbundleError.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/UnbundleError.java
new file mode 100644
index 000000000..fea779636
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/UnbundleError.java
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+import org.mozilla.gecko.sync.SyncException;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+
+public class UnbundleError extends SyncException {
+  private static final long serialVersionUID = -8709503281041697522L;
+
+  public RepositorySession failedSession;
+
+  public UnbundleError(Exception e, RepositorySession session) {
+    super(e);
+    this.failedSession = session;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/UnexpectedSessionException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/UnexpectedSessionException.java
new file mode 100644
index 000000000..0237b884b
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/UnexpectedSessionException.java
@@ -0,0 +1,26 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.synchronizer;
+
+import org.mozilla.gecko.sync.SyncException;
+import org.mozilla.gecko.sync.repositories.RepositorySession;
+
+/**
+ * An exception class that indicates that a session was passed
+ * to a begin callback and wasn't expected.
+ *
+ * This shouldn't occur.
+ *
+ * @author rnewman
+ *
+ */
+public class UnexpectedSessionException extends SyncException {
+  private static final long serialVersionUID = 949010933527484721L;
+  public RepositorySession session;
+
+  public UnexpectedSessionException(RepositorySession session) {
+    this.session = session;
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/telemetry/TelemetryContract.java b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/telemetry/TelemetryContract.java
new file mode 100644
index 000000000..e3e134fe5
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/telemetry/TelemetryContract.java
@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.telemetry;
+
+public class TelemetryContract {
+  /**
+   * We are a Sync 1.1 (legacy) client, and we downloaded a migration sentinel.
+   */
+  public static final String SYNC11_MIGRATION_SENTINELS_SEEN = "FENNEC_SYNC11_MIGRATION_SENTINELS_SEEN";
+
+  /**
+   * We are a Sync 1.1 (legacy) client and we have downloaded a migration
+   * sentinel, but there was an error creating a Firefox Account from that
+   * sentinel.
+   * <p>
+   * We have logged the error and are ignoring that sentinel.
+   */
+  public static final String SYNC11_MIGRATIONS_FAILED = "FENNEC_SYNC11_MIGRATIONS_FAILED";
+
+  /**
+   * We are a Sync 1.1 (legacy) client and we have downloaded a migration
+   * sentinel, and there was no reported error creating a Firefox Account from
+   * that sentinel.
+   * <p>
+   * We have created a Firefox Account corresponding to the sentinel and have
+   * queued the existing Old Sync account for removal.
+   */
+  public static final String SYNC11_MIGRATIONS_SUCCEEDED = "FENNEC_SYNC11_MIGRATIONS_SUCCEEDED";
+
+  /**
+   * We are (now) a Sync 1.5 (Firefox Accounts-based) client that migrated from
+   * Sync 1.1. We have presented the user the "complete upgrade" notification.
+   * <p>
+   * We will offer every time a sync is triggered, including when a notification
+   * is already pending.
+   */
+  public static final String SYNC11_MIGRATION_NOTIFICATIONS_OFFERED = "FENNEC_SYNC11_MIGRATION_NOTIFICATIONS_OFFERED";
+
+  /**
+   * We are (now) a Sync 1.5 (Firefox Accounts-based) client that migrated from
+   * Sync 1.1. We have presented the user the "complete upgrade" notification
+   * and they have successfully completed the upgrade process by entering their
+   * Firefox Account credentials.
+   */
+  public static final String SYNC11_MIGRATIONS_COMPLETED = "FENNEC_SYNC11_MIGRATIONS_COMPLETED";
+
+  public static final String SYNC_STARTED = "FENNEC_SYNC_NUMBER_OF_SYNCS_STARTED";
+
+  public static final String SYNC_COMPLETED = "FENNEC_SYNC_NUMBER_OF_SYNCS_COMPLETED";
+
+  public static final String SYNC_FAILED = "FENNEC_SYNC_NUMBER_OF_SYNCS_FAILED";
+
+  public static final String SYNC_FAILED_BACKOFF = "FENNEC_SYNC_NUMBER_OF_SYNCS_FAILED_BACKOFF";
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerClient.java b/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerClient.java
new file mode 100644
index 000000000..9ee014dcb
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerClient.java
@@ -0,0 +1,330 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.tokenserver;
+
+import java.io.IOException;
+import java.net.URI;
+import java.security.GeneralSecurityException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.Executor;
+
+import org.json.simple.JSONObject;
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.background.fxa.SkewHandler;
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.NonArrayJSONException;
+import org.mozilla.gecko.sync.NonObjectJSONException;
+import org.mozilla.gecko.sync.UnexpectedJSONException.BadRequiredFieldJSONException;
+import org.mozilla.gecko.sync.net.AuthHeaderProvider;
+import org.mozilla.gecko.sync.net.BaseResource;
+import org.mozilla.gecko.sync.net.BaseResourceDelegate;
+import org.mozilla.gecko.sync.net.BrowserIDAuthHeaderProvider;
+import org.mozilla.gecko.sync.net.SyncResponse;
+import org.mozilla.gecko.tokenserver.TokenServerException.TokenServerConditionsRequiredException;
+import org.mozilla.gecko.tokenserver.TokenServerException.TokenServerInvalidCredentialsException;
+import org.mozilla.gecko.tokenserver.TokenServerException.TokenServerMalformedRequestException;
+import org.mozilla.gecko.tokenserver.TokenServerException.TokenServerMalformedResponseException;
+import org.mozilla.gecko.tokenserver.TokenServerException.TokenServerUnknownServiceException;
+
+import ch.boye.httpclientandroidlib.Header;
+import ch.boye.httpclientandroidlib.HttpHeaders;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.ClientProtocolException;
+import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
+import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
+import ch.boye.httpclientandroidlib.message.BasicHeader;
+
+/**
+ * HTTP client for interacting with the Mozilla Services Token Server API v1.0,
+ * as documented at
+ * <a href="http://docs.services.mozilla.com/token/apis.html">http://docs.services.mozilla.com/token/apis.html</a>.
+ * <p>
+ * A token server accepts some authorization credential and returns a different
+ * authorization credential. Usually, it used to exchange a public-key
+ * authorization token that is expensive to validate for a symmetric-key
+ * authorization that is cheap to validate. For example, we might exchange a
+ * BrowserID assertion for a HAWK id and key pair.
+ */
+public class TokenServerClient {
+  protected static final String LOG_TAG = "TokenServerClient";
+
+  public static final String JSON_KEY_API_ENDPOINT = "api_endpoint";
+  public static final String JSON_KEY_CONDITION_URLS = "condition_urls";
+  public static final String JSON_KEY_DURATION = "duration";
+  public static final String JSON_KEY_ERRORS = "errors";
+  public static final String JSON_KEY_ID = "id";
+  public static final String JSON_KEY_KEY = "key";
+  public static final String JSON_KEY_UID = "uid";
+
+  public static final String HEADER_CONDITIONS_ACCEPTED = "X-Conditions-Accepted";
+  public static final String HEADER_CLIENT_STATE = "X-Client-State";
+
+  protected final Executor executor;
+  protected final URI uri;
+
+  public TokenServerClient(URI uri, Executor executor) {
+    if (uri == null) {
+      throw new IllegalArgumentException("uri must not be null");
+    }
+    if (executor == null) {
+      throw new IllegalArgumentException("executor must not be null");
+    }
+    this.uri = uri;
+    this.executor = executor;
+  }
+
+  protected void invokeHandleSuccess(final TokenServerClientDelegate delegate, final TokenServerToken token) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        delegate.handleSuccess(token);
+      }
+    });
+  }
+
+  protected void invokeHandleFailure(final TokenServerClientDelegate delegate, final TokenServerException e) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        delegate.handleFailure(e);
+      }
+    });
+  }
+
+  /**
+   * Notify the delegate that some kind of backoff header (X-Backoff,
+   * X-Weave-Backoff, Retry-After) was received and should be acted upon.
+   *
+   * This method is non-terminal, and will be followed by a separate
+   * <code>invoke*</code> call.
+   *
+   * @param delegate
+   *          the delegate to inform.
+   * @param backoffSeconds
+   *          the number of seconds for which the system should wait before
+   *          making another token server request to this server.
+   */
+  protected void notifyBackoff(final TokenServerClientDelegate delegate, final int backoffSeconds) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        delegate.handleBackoff(backoffSeconds);
+      }
+    });
+  }
+
+  protected void invokeHandleError(final TokenServerClientDelegate delegate, final Exception e) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        delegate.handleError(e);
+      }
+    });
+  }
+
+  public TokenServerToken processResponse(SyncResponse res) throws TokenServerException {
+    int statusCode = res.getStatusCode();
+
+    Logger.debug(LOG_TAG, "Got token response with status code " + statusCode + ".");
+
+    // Responses should *always* be JSON, even in the case of 4xx and 5xx
+    // errors. If we don't see JSON, the server is likely very unhappy.
+    final Header contentType = res.getContentType();
+    if (contentType == null) {
+      throw new TokenServerMalformedResponseException(null, "Non-JSON response Content-Type.");
+    }
+
+    final String type = contentType.getValue();
+    if (!type.equals("application/json") &&
+        !type.startsWith("application/json;")) {
+      Logger.warn(LOG_TAG, "Got non-JSON response with Content-Type " +
+          contentType + ". Misconfigured server?");
+      throw new TokenServerMalformedResponseException(null, "Non-JSON response Content-Type.");
+    }
+
+    // Responses should *always* be a valid JSON object.
+    // It turns out that right now they're not always, but that's a server bug...
+    ExtendedJSONObject result;
+    try {
+      result = res.jsonObjectBody();
+    } catch (Exception e) {
+      Logger.debug(LOG_TAG, "Malformed token response.", e);
+      throw new TokenServerMalformedResponseException(null, e);
+    }
+
+    // The service shouldn't have any 3xx, so we don't need to handle those.
+    if (res.getStatusCode() != 200) {
+      // We should have a (Cornice) error report in the JSON. We log that to
+      // help with debugging.
+      List<ExtendedJSONObject> errorList = new ArrayList<ExtendedJSONObject>();
+
+      if (result.containsKey(JSON_KEY_ERRORS)) {
+        try {
+          for (Object error : result.getArray(JSON_KEY_ERRORS)) {
+            Logger.warn(LOG_TAG, "" + error);
+
+            if (error instanceof JSONObject) {
+              errorList.add(new ExtendedJSONObject((JSONObject) error));
+            }
+          }
+        } catch (NonArrayJSONException e) {
+          Logger.warn(LOG_TAG, "Got non-JSON array '" + JSON_KEY_ERRORS + "'.", e);
+        }
+      }
+
+      if (statusCode == 400) {
+        throw new TokenServerMalformedRequestException(errorList, result.toJSONString());
+      }
+
+      if (statusCode == 401) {
+        throw new TokenServerInvalidCredentialsException(errorList, result.toJSONString());
+      }
+
+      // 403 should represent a "condition acceptance needed" response.
+      //
+      // The extra validation of "urls" is important. We don't want to signal
+      // conditions required unless we are absolutely sure that is what the
+      // server is asking for.
+      if (statusCode == 403) {
+        // Bug 792674 and Bug 783598: make this testing simpler. For now, we
+        // check that errors is an array, and take any condition_urls from the
+        // first element.
+
+        try {
+          if (errorList == null || errorList.isEmpty()) {
+            throw new TokenServerMalformedResponseException(errorList, "403 response without proper fields.");
+          }
+
+          ExtendedJSONObject error = errorList.get(0);
+
+          ExtendedJSONObject condition_urls = error.getObject(JSON_KEY_CONDITION_URLS);
+          if (condition_urls != null) {
+            throw new TokenServerConditionsRequiredException(condition_urls);
+          }
+        } catch (NonObjectJSONException e) {
+          Logger.warn(LOG_TAG, "Got non-JSON error object.");
+        }
+
+        throw new TokenServerMalformedResponseException(errorList, "403 response without proper fields.");
+      }
+
+      if (statusCode == 404) {
+        throw new TokenServerUnknownServiceException(errorList);
+      }
+
+      // We shouldn't ever get here...
+      throw new TokenServerException(errorList);
+    }
+
+    try {
+      result.throwIfFieldsMissingOrMisTyped(new String[] { JSON_KEY_ID, JSON_KEY_KEY, JSON_KEY_API_ENDPOINT }, String.class);
+      result.throwIfFieldsMissingOrMisTyped(new String[] { JSON_KEY_UID }, Long.class);
+    } catch (BadRequiredFieldJSONException e ) {
+      throw new TokenServerMalformedResponseException(null, e);
+    }
+
+    Logger.debug(LOG_TAG, "Successful token response: " + result.getString(JSON_KEY_ID));
+
+    return new TokenServerToken(result.getString(JSON_KEY_ID),
+        result.getString(JSON_KEY_KEY),
+        result.get(JSON_KEY_UID).toString(),
+        result.getString(JSON_KEY_API_ENDPOINT));
+  }
+
+  public static class TokenFetchResourceDelegate extends BaseResourceDelegate {
+    private final TokenServerClient         client;
+    private final TokenServerClientDelegate delegate;
+    private final String                    assertion;
+    private final String                    clientState;
+    private final BaseResource              resource;
+    private final boolean                   conditionsAccepted;
+
+    public TokenFetchResourceDelegate(TokenServerClient client,
+                                      BaseResource resource,
+                                      TokenServerClientDelegate delegate,
+                                      String assertion, String clientState,
+                                      boolean conditionsAccepted) {
+      super(resource);
+      this.client = client;
+      this.delegate = delegate;
+      this.assertion = assertion;
+      this.clientState = clientState;
+      this.resource = resource;
+      this.conditionsAccepted = conditionsAccepted;
+    }
+
+    @Override
+    public String getUserAgent() {
+      return delegate.getUserAgent();
+    }
+
+    @Override
+    public void handleHttpResponse(HttpResponse response) {
+      // Skew.
+      SkewHandler skewHandler = SkewHandler.getSkewHandlerForResource(resource);
+      skewHandler.updateSkew(response, System.currentTimeMillis());
+
+      // Extract backoff regardless of whether this was an error response, and
+      // Retry-After for 503 responses. The error will be handled elsewhere.)
+      SyncResponse res = new SyncResponse(response);
+      final boolean includeRetryAfter = res.getStatusCode() == 503;
+      int backoffInSeconds = res.totalBackoffInSeconds(includeRetryAfter);
+      if (backoffInSeconds > -1) {
+        client.notifyBackoff(delegate, backoffInSeconds);
+      }
+
+      try {
+        TokenServerToken token = client.processResponse(res);
+        client.invokeHandleSuccess(delegate, token);
+      } catch (TokenServerException e) {
+        client.invokeHandleFailure(delegate, e);
+      }
+    }
+
+    @Override
+    public void handleTransportException(GeneralSecurityException e) {
+      client.invokeHandleError(delegate, e);
+    }
+
+    @Override
+    public void handleHttpProtocolException(ClientProtocolException e) {
+      client.invokeHandleError(delegate, e);
+    }
+
+    @Override
+    public void handleHttpIOException(IOException e) {
+      client.invokeHandleError(delegate, e);
+    }
+
+    @Override
+    public AuthHeaderProvider getAuthHeaderProvider() {
+      return new BrowserIDAuthHeaderProvider(assertion);
+    }
+
+    @Override
+    public void addHeaders(HttpRequestBase request, DefaultHttpClient client) {
+      String host = request.getURI().getHost();
+      request.setHeader(new BasicHeader(HttpHeaders.HOST, host));
+      if (clientState != null) {
+        request.setHeader(new BasicHeader(HEADER_CLIENT_STATE, clientState));
+      }
+      if (conditionsAccepted) {
+        request.addHeader(HEADER_CONDITIONS_ACCEPTED, "1");
+      }
+    }
+  }
+
+  public void getTokenFromBrowserIDAssertion(final String assertion,
+                                             final boolean conditionsAccepted,
+                                             final String clientState,
+                                             final TokenServerClientDelegate delegate) {
+    final BaseResource resource = new BaseResource(this.uri);
+    resource.delegate = new TokenFetchResourceDelegate(this, resource, delegate,
+                                                       assertion, clientState,
+                                                       conditionsAccepted);
+    resource.get();
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerClientDelegate.java b/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerClientDelegate.java
new file mode 100644
index 000000000..e1dfe2422
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerClientDelegate.java
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.tokenserver;
+
+
+public interface TokenServerClientDelegate {
+  void handleSuccess(TokenServerToken token);
+  void handleFailure(TokenServerException e);
+  void handleError(Exception e);
+
+  /**
+   * Might be called multiple times, in addition to the other terminating handler methods.
+   */
+  void handleBackoff(int backoffSeconds);
+
+  public String getUserAgent();
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerException.java b/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerException.java
new file mode 100644
index 000000000..099e51867
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerException.java
@@ -0,0 +1,89 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.tokenserver;
+
+import java.util.List;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+
+public class TokenServerException extends Exception {
+  private static final long serialVersionUID = 7185692034925819696L;
+
+  public final List<ExtendedJSONObject> errors;
+
+  public TokenServerException(List<ExtendedJSONObject> errors) {
+    super();
+    this.errors = errors;
+  }
+
+  public TokenServerException(List<ExtendedJSONObject> errors, String string) {
+    super(string);
+    this.errors = errors;
+  }
+
+  public TokenServerException(List<ExtendedJSONObject> errors, Throwable e) {
+    super(e);
+    this.errors = errors;
+  }
+
+  public static class TokenServerConditionsRequiredException extends TokenServerException {
+    private static final long serialVersionUID = 7578072663150608399L;
+
+    public final ExtendedJSONObject conditionUrls;
+
+    public TokenServerConditionsRequiredException(ExtendedJSONObject urls) {
+      super(null);
+      this.conditionUrls = urls;
+    }
+  }
+
+  public static class TokenServerInvalidCredentialsException extends TokenServerException {
+    private static final long serialVersionUID = 7578072663150608398L;
+
+    public TokenServerInvalidCredentialsException(List<ExtendedJSONObject> errors) {
+      super(errors);
+    }
+
+    public TokenServerInvalidCredentialsException(List<ExtendedJSONObject> errors, String message) {
+      super(errors, message);
+    }
+  }
+
+  public static class TokenServerUnknownServiceException extends TokenServerException {
+    private static final long serialVersionUID = 7578072663150608397L;
+
+    public TokenServerUnknownServiceException(List<ExtendedJSONObject> errors) {
+      super(errors);
+    }
+
+    public TokenServerUnknownServiceException(List<ExtendedJSONObject> errors, String message) {
+      super(errors, message);
+    }
+  }
+
+  public static class TokenServerMalformedRequestException extends TokenServerException {
+    private static final long serialVersionUID = 7578072663150608396L;
+
+    public TokenServerMalformedRequestException(List<ExtendedJSONObject> errors) {
+      super(errors);
+    }
+
+    public TokenServerMalformedRequestException(List<ExtendedJSONObject> errors, String message) {
+      super(errors, message);
+    }
+  }
+
+  public static class TokenServerMalformedResponseException extends TokenServerException {
+    private static final long serialVersionUID = 7578072663150608395L;
+
+    public TokenServerMalformedResponseException(List<ExtendedJSONObject> errors, String message) {
+      super(errors, message);
+    }
+
+    public TokenServerMalformedResponseException(List<ExtendedJSONObject> errors, Throwable e) {
+      super(errors, e);
+    }
+  }
+}
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerToken.java b/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerToken.java
new file mode 100644
index 000000000..916586cdc
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/tokenserver/TokenServerToken.java
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.tokenserver;
+
+public class TokenServerToken {
+  public final String id;
+  public final String key;
+  public final String uid;
+  public final String endpoint;
+
+  public TokenServerToken(String id, String key, String uid, String endpoint) {
+    this.id = id;
+    this.key = key;
+    this.uid = uid;
+    this.endpoint = endpoint;
+  }
+}
\ No newline at end of file
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/util/PRNGFixes.java b/mobile/android/services/src/main/java/org/mozilla/gecko/util/PRNGFixes.java
new file mode 100644
index 000000000..ebb50f765
--- /dev/null
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/util/PRNGFixes.java
@@ -0,0 +1,339 @@
+/*
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will Google be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, as long as the origin is not misrepresented.
+ */
+
+package org.mozilla.gecko.util;
+
+import android.os.Build;
+import android.os.Process;
+import android.util.Log;
+
+import java.io.ByteArrayOutputStream;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.UnsupportedEncodingException;
+import java.security.NoSuchAlgorithmException;
+import java.security.Provider;
+import java.security.SecureRandom;
+import java.security.SecureRandomSpi;
+import java.security.Security;
+
+/**
+ * Fixes for the output of the default PRNG having low entropy.
+ *
+ * The fixes need to be applied via {@link #apply()} before any use of Java
+ * Cryptography Architecture primitives. A good place to invoke them is in the
+ * application's {@code onCreate}.
+ */
+public final class PRNGFixes {
+    private static final long serialVersionUID = -687331492884005033L;
+
+    private static final int VERSION_CODE_JELLY_BEAN = 16;
+    private static final int VERSION_CODE_JELLY_BEAN_MR2 = 18;
+    private static final byte[] BUILD_FINGERPRINT_AND_DEVICE_SERIAL =
+        getBuildFingerprintAndDeviceSerial();
+
+    /** Hidden constructor to prevent instantiation. */
+    private PRNGFixes() {}
+
+    /**
+     * Applies all fixes.
+     *
+     * @throws SecurityException if a fix is needed but could not be applied.
+     */
+    public static void apply() {
+        applyOpenSSLFix();
+        installLinuxPRNGSecureRandom();
+    }
+
+    /**
+     * Applies the fix for OpenSSL PRNG having low entropy. Does nothing if the
+     * fix is not needed.
+     *
+     * @throws SecurityException if the fix is needed but could not be applied.
+     */
+    private static void applyOpenSSLFix() throws SecurityException {
+        if ((Build.VERSION.SDK_INT < VERSION_CODE_JELLY_BEAN)
+                || (Build.VERSION.SDK_INT > VERSION_CODE_JELLY_BEAN_MR2)) {
+            // No need to apply the fix
+            return;
+        }
+
+        try {
+            // Mix in the device- and invocation-specific seed.
+            Class.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")
+                    .getMethod("RAND_seed", byte[].class)
+                    .invoke(null, generateSeed());
+
+            // Mix output of Linux PRNG into OpenSSL's PRNG
+            int bytesRead = (Integer) Class.forName(
+                    "org.apache.harmony.xnet.provider.jsse.NativeCrypto")
+                    .getMethod("RAND_load_file", String.class, long.class)
+                    .invoke(null, "/dev/urandom", 1024);
+            if (bytesRead != 1024) {
+                throw new IOException(
+                        "Unexpected number of bytes read from Linux PRNG: "
+                                + bytesRead);
+            }
+        } catch (Exception e) {
+            throw new SecurityException("Failed to seed OpenSSL PRNG", e);
+        }
+    }
+
+    /**
+     * Installs a Linux PRNG-backed {@code SecureRandom} implementation as the
+     * default. Does nothing if the implementation is already the default or if
+     * there is not need to install the implementation.
+     *
+     * @throws SecurityException if the fix is needed but could not be applied.
+     */
+    private static void installLinuxPRNGSecureRandom()
+            throws SecurityException {
+        if (Build.VERSION.SDK_INT > VERSION_CODE_JELLY_BEAN_MR2) {
+            // No need to apply the fix
+            return;
+        }
+
+        // Install a Linux PRNG-based SecureRandom implementation as the
+        // default, if not yet installed.
+        Provider[] secureRandomProviders =
+                Security.getProviders("SecureRandom.SHA1PRNG");
+        if ((secureRandomProviders == null)
+                || (secureRandomProviders.length < 1)
+                || (!LinuxPRNGSecureRandomProvider.class.equals(
+                        secureRandomProviders[0].getClass()))) {
+            Security.insertProviderAt(new LinuxPRNGSecureRandomProvider(), 1);
+        }
+
+        // Assert that new SecureRandom() and
+        // SecureRandom.getInstance("SHA1PRNG") return a SecureRandom backed
+        // by the Linux PRNG-based SecureRandom implementation.
+        SecureRandom rng1 = new SecureRandom();
+        if (!LinuxPRNGSecureRandomProvider.class.equals(
+                rng1.getProvider().getClass())) {
+            throw new SecurityException(
+                    "new SecureRandom() backed by wrong Provider: "
+                            + rng1.getProvider().getClass());
+        }
+
+        SecureRandom rng2;
+        try {
+            rng2 = SecureRandom.getInstance("SHA1PRNG");
+        } catch (NoSuchAlgorithmException e) {
+            throw new SecurityException("SHA1PRNG not available", e);
+        }
+        if (!LinuxPRNGSecureRandomProvider.class.equals(
+                rng2.getProvider().getClass())) {
+            throw new SecurityException(
+                    "SecureRandom.getInstance(\"SHA1PRNG\") backed by wrong"
+                    + " Provider: " + rng2.getProvider().getClass());
+        }
+    }
+
+    /**
+     * {@code Provider} of {@code SecureRandom} engines which pass through
+     * all requests to the Linux PRNG.
+     */
+    private static class LinuxPRNGSecureRandomProvider extends Provider {
+        private static final long serialVersionUID = -686731492884005033L;
+
+        public LinuxPRNGSecureRandomProvider() {
+            super("LinuxPRNG",
+                    1.0,
+                    "A Linux-specific random number provider that uses"
+                        + " /dev/urandom");
+            // Although /dev/urandom is not a SHA-1 PRNG, some apps
+            // explicitly request a SHA1PRNG SecureRandom and we thus need to
+            // prevent them from getting the default implementation whose output
+            // may have low entropy.
+            put("SecureRandom.SHA1PRNG", LinuxPRNGSecureRandom.class.getName());
+            put("SecureRandom.SHA1PRNG ImplementedIn", "Software");
+        }
+    }
+
+    /**
+     * {@link SecureRandomSpi} which passes all requests to the Linux PRNG
+     * ({@code /dev/urandom}).
+     */
+    public static class LinuxPRNGSecureRandom extends SecureRandomSpi {
+        private static final long serialVersionUID = -696231492884005033L;
+
+        /*
+         * IMPLEMENTATION NOTE: Requests to generate bytes and to mix in a seed
+         * are passed through to the Linux PRNG (/dev/urandom). Instances of
+         * this class seed themselves by mixing in the current time, PID, UID,
+         * build fingerprint, and hardware serial number (where available) into
+         * Linux PRNG.
+         *
+         * Concurrency: Read requests to the underlying Linux PRNG are
+         * serialized (on sLock) to ensure that multiple threads do not get
+         * duplicated PRNG output.
+         */
+
+        private static final File URANDOM_FILE = new File("/dev/urandom");
+
+        private static final Object sLock = new Object();
+
+        /**
+         * Input stream for reading from Linux PRNG or {@code null} if not yet
+         * opened.
+         *
+         * @GuardedBy("sLock")
+         */
+        private static DataInputStream sUrandomIn;
+
+        /**
+         * Output stream for writing to Linux PRNG or {@code null} if not yet
+         * opened.
+         *
+         * @GuardedBy("sLock")
+         */
+        private static OutputStream sUrandomOut;
+
+        /**
+         * Whether this engine instance has been seeded. This is needed because
+         * each instance needs to seed itself if the client does not explicitly
+         * seed it.
+         */
+        private boolean mSeeded;
+
+        @Override
+        protected void engineSetSeed(byte[] bytes) {
+            try {
+                OutputStream out;
+                synchronized (sLock) {
+                    out = getUrandomOutputStream();
+                }
+                out.write(bytes);
+                out.flush();
+            } catch (IOException e) {
+                // On a small fraction of devices /dev/urandom is not writable.
+                // Log and ignore.
+                Log.w(PRNGFixes.class.getSimpleName(),
+                        "Failed to mix seed into " + URANDOM_FILE);
+            } finally {
+                mSeeded = true;
+            }
+        }
+
+        @Override
+        protected void engineNextBytes(byte[] bytes) {
+            if (!mSeeded) {
+                // Mix in the device- and invocation-specific seed.
+                engineSetSeed(generateSeed());
+            }
+
+            try {
+                DataInputStream in;
+                synchronized (sLock) {
+                    in = getUrandomInputStream();
+                }
+                synchronized (in) {
+                    in.readFully(bytes);
+                }
+            } catch (IOException e) {
+                throw new SecurityException(
+                        "Failed to read from " + URANDOM_FILE, e);
+            }
+        }
+
+        @Override
+        protected byte[] engineGenerateSeed(int size) {
+            byte[] seed = new byte[size];
+            engineNextBytes(seed);
+            return seed;
+        }
+
+        private DataInputStream getUrandomInputStream() {
+            synchronized (sLock) {
+                if (sUrandomIn == null) {
+                    // NOTE: Consider inserting a BufferedInputStream between
+                    // DataInputStream and FileInputStream if you need higher
+                    // PRNG output performance and can live with future PRNG
+                    // output being pulled into this process prematurely.
+                    try {
+                        sUrandomIn = new DataInputStream(
+                                new FileInputStream(URANDOM_FILE));
+                    } catch (IOException e) {
+                        throw new SecurityException("Failed to open "
+                                + URANDOM_FILE + " for reading", e);
+                    }
+                }
+                return sUrandomIn;
+            }
+        }
+
+        private OutputStream getUrandomOutputStream() throws IOException {
+            synchronized (sLock) {
+                if (sUrandomOut == null) {
+                    sUrandomOut = new FileOutputStream(URANDOM_FILE);
+                }
+                return sUrandomOut;
+            }
+        }
+    }
+
+    /**
+     * Generates a device- and invocation-specific seed to be mixed into the
+     * Linux PRNG.
+     */
+    private static byte[] generateSeed() {
+        try {
+            ByteArrayOutputStream seedBuffer = new ByteArrayOutputStream();
+            DataOutputStream seedBufferOut =
+                    new DataOutputStream(seedBuffer);
+            seedBufferOut.writeLong(System.currentTimeMillis());
+            seedBufferOut.writeLong(System.nanoTime());
+            seedBufferOut.writeInt(Process.myPid());
+            seedBufferOut.writeInt(Process.myUid());
+            seedBufferOut.write(BUILD_FINGERPRINT_AND_DEVICE_SERIAL);
+            seedBufferOut.close();
+            return seedBuffer.toByteArray();
+        } catch (IOException e) {
+            throw new SecurityException("Failed to generate seed", e);
+        }
+    }
+
+    /**
+     * Gets the hardware serial number of this device.
+     *
+     * @return serial number or {@code null} if not available.
+     */
+    private static String getDeviceSerialNumber() {
+        // We're using the Reflection API because Build.SERIAL is only available
+        // since API Level 9 (Gingerbread, Android 2.3).
+        try {
+            return (String) Build.class.getField("SERIAL").get(null);
+        } catch (Exception ignored) {
+            return null;
+        }
+    }
+
+    private static byte[] getBuildFingerprintAndDeviceSerial() {
+        StringBuilder result = new StringBuilder();
+        String fingerprint = Build.FINGERPRINT;
+        if (fingerprint != null) {
+            result.append(fingerprint);
+        }
+        String serial = getDeviceSerialNumber();
+        if (serial != null) {
+            result.append(serial);
+        }
+        try {
+            return result.toString().getBytes("UTF-8");
+        } catch (UnsupportedEncodingException e) {
+            throw new RuntimeException("UTF-8 encoding not supported");
+        }
+    }
+}
diff --git a/mobile/android/services/src/main/res/drawable-hdpi/fxaccount_sync_error.png b/mobile/android/services/src/main/res/drawable-hdpi/fxaccount_sync_error.png
new file mode 100644
index 000000000..3a2cbc4bf
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-hdpi/fxaccount_sync_error.png
diff --git a/mobile/android/services/src/main/res/drawable-hdpi/sync_avatar_default.png b/mobile/android/services/src/main/res/drawable-hdpi/sync_avatar_default.png
new file mode 100644
index 000000000..caa6ed246
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-hdpi/sync_avatar_default.png
diff --git a/mobile/android/services/src/main/res/drawable-hdpi/sync_desktop.png b/mobile/android/services/src/main/res/drawable-hdpi/sync_desktop.png
new file mode 100644
index 000000000..abf87f16c
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-hdpi/sync_desktop.png
diff --git a/mobile/android/services/src/main/res/drawable-hdpi/sync_desktop_inactive.png b/mobile/android/services/src/main/res/drawable-hdpi/sync_desktop_inactive.png
new file mode 100644
index 000000000..869dbf402
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-hdpi/sync_desktop_inactive.png
diff --git a/mobile/android/services/src/main/res/drawable-hdpi/sync_mobile.png b/mobile/android/services/src/main/res/drawable-hdpi/sync_mobile.png
new file mode 100644
index 000000000..4b25152b2
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-hdpi/sync_mobile.png
diff --git a/mobile/android/services/src/main/res/drawable-hdpi/sync_mobile_inactive.png b/mobile/android/services/src/main/res/drawable-hdpi/sync_mobile_inactive.png
new file mode 100644
index 000000000..e9401797d
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-hdpi/sync_mobile_inactive.png
diff --git a/mobile/android/services/src/main/res/drawable-hdpi/sync_promo.png b/mobile/android/services/src/main/res/drawable-hdpi/sync_promo.png
new file mode 100644
index 000000000..ea2150508
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-hdpi/sync_promo.png
diff --git a/mobile/android/services/src/main/res/drawable-xhdpi/fxaccount_sync_error.png b/mobile/android/services/src/main/res/drawable-xhdpi/fxaccount_sync_error.png
new file mode 100644
index 000000000..f9bf849fa
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xhdpi/fxaccount_sync_error.png
diff --git a/mobile/android/services/src/main/res/drawable-xhdpi/sync_desktop.png b/mobile/android/services/src/main/res/drawable-xhdpi/sync_desktop.png
new file mode 100644
index 000000000..30d5b5c09
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xhdpi/sync_desktop.png
diff --git a/mobile/android/services/src/main/res/drawable-xhdpi/sync_desktop_inactive.png b/mobile/android/services/src/main/res/drawable-xhdpi/sync_desktop_inactive.png
new file mode 100644
index 000000000..1b5b00a75
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xhdpi/sync_desktop_inactive.png
diff --git a/mobile/android/services/src/main/res/drawable-xhdpi/sync_mobile.png b/mobile/android/services/src/main/res/drawable-xhdpi/sync_mobile.png
new file mode 100644
index 000000000..2c3f45d4a
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xhdpi/sync_mobile.png
diff --git a/mobile/android/services/src/main/res/drawable-xhdpi/sync_mobile_inactive.png b/mobile/android/services/src/main/res/drawable-xhdpi/sync_mobile_inactive.png
new file mode 100644
index 000000000..60fd77c8a
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xhdpi/sync_mobile_inactive.png
diff --git a/mobile/android/services/src/main/res/drawable-xhdpi/sync_promo.png b/mobile/android/services/src/main/res/drawable-xhdpi/sync_promo.png
new file mode 100644
index 000000000..63f1a55ad
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xhdpi/sync_promo.png
diff --git a/mobile/android/services/src/main/res/drawable-xxhdpi/fxaccount_sync_error.png b/mobile/android/services/src/main/res/drawable-xxhdpi/fxaccount_sync_error.png
new file mode 100644
index 000000000..7555bc9d6
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xxhdpi/fxaccount_sync_error.png
diff --git a/mobile/android/services/src/main/res/drawable-xxhdpi/sync_avatar_default.png b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_avatar_default.png
new file mode 100644
index 000000000..16d127882
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_avatar_default.png
diff --git a/mobile/android/services/src/main/res/drawable-xxhdpi/sync_desktop.png b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_desktop.png
new file mode 100644
index 000000000..9bb9a55c2
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_desktop.png
diff --git a/mobile/android/services/src/main/res/drawable-xxhdpi/sync_desktop_inactive.png b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_desktop_inactive.png
new file mode 100644
index 000000000..c3fe0ec1d
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_desktop_inactive.png
diff --git a/mobile/android/services/src/main/res/drawable-xxhdpi/sync_mobile.png b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_mobile.png
new file mode 100644
index 000000000..400ddf65b
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_mobile.png
diff --git a/mobile/android/services/src/main/res/drawable-xxhdpi/sync_mobile_inactive.png b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_mobile_inactive.png
new file mode 100644
index 000000000..a688b0d7b
--- /dev/null
+++ b/mobile/android/services/src/main/res/drawable-xxhdpi/sync_mobile_inactive.png
diff --git a/mobile/android/services/src/main/res/layout/fxaccount_preference_list_fragment.xml b/mobile/android/services/src/main/res/layout/fxaccount_preference_list_fragment.xml
new file mode 100644
index 000000000..acaafc7c2
--- /dev/null
+++ b/mobile/android/services/src/main/res/layout/fxaccount_preference_list_fragment.xml
@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/*
+** Copyright 2010, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+-->
+
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="vertical"
+    android:layout_height="fill_parent"
+    android:layout_width="fill_parent"
+    android:background="@android:color/transparent">
+
+    <ListView android:id="@android:id/list"
+        android:layout_width="fill_parent"
+        android:layout_height="0px"
+        android:layout_weight="1"
+        android:paddingTop="0dip"
+        android:paddingBottom="@dimen/preference_fragment_padding_bottom"
+        android:paddingLeft="@dimen/preference_fragment_padding_side"
+        android:paddingRight="@dimen/preference_fragment_padding_side"
+        android:scrollbarStyle="@integer/preference_fragment_scrollbarStyle"
+        android:clipToPadding="false"
+        android:drawSelectorOnTop="false"
+        android:cacheColorHint="@android:color/transparent"
+        android:scrollbarAlwaysDrawVerticalTrack="true" />
+
+</LinearLayout>
diff --git a/mobile/android/services/src/main/res/layout/fxaccount_status_error_preference.xml b/mobile/android/services/src/main/res/layout/fxaccount_status_error_preference.xml
new file mode 100644
index 000000000..4a507cddd
--- /dev/null
+++ b/mobile/android/services/src/main/res/layout/fxaccount_status_error_preference.xml
@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="fill_parent"
+    android:layout_height="wrap_content"
+    android:background="@color/fxaccount_error_preference_backgroundcolor"
+    android:gravity="center_vertical"
+    android:minHeight="?android:attr/listPreferredItemHeight"
+    android:paddingRight="?android:attr/scrollbarSize" >
+
+    <LinearLayout
+        android:layout_width="wrap_content"
+        android:layout_height="match_parent"
+        android:gravity="center"
+        android:minWidth="0dp"
+        android:orientation="horizontal" >
+
+        <ImageView
+            android:id="@+android:id/icon"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center"
+            android:minWidth="48dip"
+            android:padding="10dip" />
+    </LinearLayout>
+
+    <RelativeLayout
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="6dip"
+        android:layout_marginLeft="15dip"
+        android:layout_marginRight="6dip"
+        android:layout_marginTop="6dip"
+        android:layout_weight="1" >
+
+        <TextView
+            android:id="@+android:id/title"
+            style="@style/FxAccountTextItem"
+            android:layout_width="fill_parent"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_horizontal"
+            android:gravity="center_vertical" >
+        </TextView>
+    </RelativeLayout>
+
+    <!-- We ignore summary and widget_frame, but they still need to be present.  We set them to be gone. -->
+
+    <TextView
+        android:id="@+android:id/summary"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:maxLines="4"
+        android:textAppearance="?android:attr/textAppearanceSmall"
+        android:textColor="?android:attr/textColorSecondary"
+        android:visibility="gone" />
+
+    <!-- Preference should place its actual preference widget here. -->
+
+    <LinearLayout
+        android:id="@+android:id/widget_frame"
+        android:layout_width="wrap_content"
+        android:layout_height="match_parent"
+        android:gravity="center"
+        android:orientation="vertical"
+        android:visibility="gone" />
+
+</LinearLayout>
diff --git a/mobile/android/services/src/main/res/layout/homescreen_prompt.xml b/mobile/android/services/src/main/res/layout/homescreen_prompt.xml
new file mode 100644
index 000000000..26d04ad17
--- /dev/null
+++ b/mobile/android/services/src/main/res/layout/homescreen_prompt.xml
@@ -0,0 +1,92 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<merge xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:clipChildren="false"
+    android:clipToPadding="false">
+
+    <RelativeLayout
+        android:id="@+id/container"
+        android:layout_width="@dimen/overlay_prompt_container_width"
+        android:layout_height="wrap_content"
+        android:layout_gravity="bottom|center"
+        android:background="@android:color/white"
+        android:clickable="true"
+        android:orientation="vertical">
+
+        <ImageView
+            android:id="@+id/close"
+            android:layout_width="24dp"
+            android:layout_height="24dp"
+            android:layout_alignParentRight="true"
+            android:layout_marginLeft="10dp"
+            android:layout_marginRight="30dp"
+            android:layout_marginTop="30dp"
+            android:ellipsize="end"
+            android:maxLines="2"
+            android:padding="6dp"
+            android:src="@drawable/tab_close_active" />
+
+        <TextView
+            android:id="@+id/title"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginBottom="6dp"
+            android:layout_marginLeft="30dp"
+            android:layout_marginTop="30dp"
+            android:layout_toLeftOf="@id/close"
+            android:fontFamily="sans-serif-light"
+            android:textColor="@color/text_and_tabs_tray_grey"
+            android:textSize="20sp"
+            tools:text="The Pokedex" />
+
+        <TextView
+            android:id="@+id/host"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_below="@id/title"
+            android:layout_marginBottom="20dp"
+            android:layout_marginLeft="30dp"
+            android:layout_marginRight="30dp"
+            android:ellipsize="end"
+            android:maxLines="1"
+            android:textColor="@color/placeholder_grey"
+            android:textSize="16sp"
+            tools:text="pokedex.org" />
+
+        <ImageView
+            android:id="@+id/icon"
+            android:layout_width="50dp"
+            android:layout_height="50dp"
+            android:layout_below="@id/host"
+            android:layout_marginBottom="20dp"
+            android:layout_marginLeft="30dp"
+            android:src="@drawable/icon" />
+
+        <Button
+            android:id="@+id/add"
+            style="@style/Widget.BaseButton"
+            android:layout_width="wrap_content"
+            android:layout_height="50dp"
+            android:layout_alignParentRight="true"
+            android:layout_below="@id/host"
+            android:layout_marginBottom="20dp"
+            android:layout_marginLeft="100dp"
+            android:layout_marginRight="30dp"
+            android:background="@drawable/button_background_action_orange_round"
+            android:paddingLeft="16dp"
+            android:paddingRight="16dp"
+            android:text="@string/promotion_add_to_homescreen"
+            android:maxLines="2"
+            android:ellipsize="end"
+            android:textColor="@android:color/white"
+            android:textSize="16sp" />
+
+    </RelativeLayout>
+</merge>
diff --git a/mobile/android/services/src/main/res/layout/simple_helper_ui.xml b/mobile/android/services/src/main/res/layout/simple_helper_ui.xml
new file mode 100644
index 000000000..f549d5c31
--- /dev/null
+++ b/mobile/android/services/src/main/res/layout/simple_helper_ui.xml
@@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<merge xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:clipChildren="false"
+    android:clipToPadding="false">
+
+    <LinearLayout
+        android:id="@+id/container"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:background="@android:color/white"
+        android:layout_gravity="bottom|center"
+        android:clickable="true"
+        android:orientation="vertical">
+
+        <ImageView
+            android:id="@+id/image"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="40dp"
+            android:layout_marginBottom="40dp"
+            android:scaleType="fitCenter"
+            android:layout_gravity="center"
+            android:adjustViewBounds="true"/>
+
+        <TextView
+            android:id="@+id/title"
+            android:layout_width="@dimen/firstrun_content_width"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center"
+            android:gravity="center"
+            android:textAppearance="@style/TextAppearance.FirstrunLight.Main"/>
+
+
+        <TextView
+            android:id="@+id/message"
+            android:layout_width="@dimen/firstrun_content_width"
+            android:layout_height="wrap_content"
+            android:paddingTop="20dp"
+            android:paddingBottom="30dp"
+            android:layout_gravity="center"
+            android:gravity="center"
+            android:textAppearance="@style/TextAppearance.FirstrunRegular.Body"
+            android:singleLine="false"/>
+
+        <Button
+            android:id="@+id/button"
+            style="@style/Widget.Firstrun.Button"
+            android:background="@drawable/button_background_action_orange_round"
+            android:layout_gravity="center"
+            android:layout_marginBottom="30dp"/>
+
+    </LinearLayout>
+</merge>
diff --git a/mobile/android/services/src/main/res/menu/fxaccount_status_menu.xml b/mobile/android/services/src/main/res/menu/fxaccount_status_menu.xml
new file mode 100644
index 000000000..16f72a7ca
--- /dev/null
+++ b/mobile/android/services/src/main/res/menu/fxaccount_status_menu.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android" >
+  <item
+      android:id="@+id/enable_debug_mode"
+      android:checkable="true"
+      android:checked="false"
+      android:title="@string/fxaccount_enable_debug_mode" />
+</menu>
diff --git a/mobile/android/services/src/main/res/values-v11/fxaccount_styles.xml b/mobile/android/services/src/main/res/values-v11/fxaccount_styles.xml
new file mode 100644
index 000000000..5c0a23db5
--- /dev/null
+++ b/mobile/android/services/src/main/res/values-v11/fxaccount_styles.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+   This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/.
+-->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <!-- FxAccountStatusActivity ActionBar -->
+    <style name="ActionBar.FxAccountStatusActivity">
+         <item name="android:displayOptions">showHome|homeAsUp|showTitle</item>
+    </style>
+
+    <style name="FxAccountTheme" parent="Gecko.Preferences" />
+
+    <style name="FxAccountTheme.FxAccountStatusActivity" parent="Gecko.Preferences">
+         <item name="android:actionBarStyle">@style/ActionBar.FxAccountStatusActivity</item>
+    </style>
+
+</resources>
diff --git a/mobile/android/services/src/main/res/values/fxaccount_colors.xml b/mobile/android/services/src/main/res/values/fxaccount_colors.xml
new file mode 100644
index 000000000..f7140faff
--- /dev/null
+++ b/mobile/android/services/src/main/res/values/fxaccount_colors.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android">
+  <color name="fxaccount_textColor">#424f59</color>
+  <color name="fxaccount_error_preference_backgroundcolor">#fad4d2</color>
+</resources>
diff --git a/mobile/android/services/src/main/res/values/fxaccount_dimens.xml b/mobile/android/services/src/main/res/values/fxaccount_dimens.xml
new file mode 100644
index 000000000..d1d44585d
--- /dev/null
+++ b/mobile/android/services/src/main/res/values/fxaccount_dimens.xml
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<resources>
+  <!-- Preference fragment padding, bottom -->
+  <dimen name="preference_fragment_padding_bottom">0dp</dimen>
+  <!-- Preference fragment padding, sides -->
+  <dimen name="preference_fragment_padding_side">16dp</dimen>
+
+  <integer name="preference_fragment_scrollbarStyle">0x02000000</integer> <!-- outsideOverlay -->
+
+  <!-- Profile avatar image height. -->
+  <dimen name="fxaccount_profile_image_height">48dp</dimen>
+  <!-- Profile avatar image width. -->
+  <dimen name="fxaccount_profile_image_width">48dp</dimen>
+</resources>
diff --git a/mobile/android/services/src/main/res/values/fxaccount_styles.xml b/mobile/android/services/src/main/res/values/fxaccount_styles.xml
new file mode 100644
index 000000000..d74efac91
--- /dev/null
+++ b/mobile/android/services/src/main/res/values/fxaccount_styles.xml
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+   This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/.
+-->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <style name="FxAccountTheme" parent="Gecko.Preferences" />
+
+    <style name="FxAccountTheme.FxAccountStatusActivity" parent="@style/FxAccountTheme">
+        <item name="android:windowNoTitle">false</item>
+    </style>
+
+    <style name="FxAccountTextItem" parent="@android:style/TextAppearance.Medium">
+        <item name="android:textColor">@color/fxaccount_textColor</item>
+        <item name="android:layout_width">fill_parent</item>
+        <item name="android:layout_height">wrap_content</item>
+        <item name="android:gravity">center_horizontal</item>
+        <item name="android:textSize">14sp</item>
+        <item name="android:layout_marginBottom">10dp</item>
+        <item name="android:layout_marginLeft">10dp</item>
+        <item name="android:layout_marginRight">10dp</item>
+    </style>
+
+</resources>
diff --git a/mobile/android/services/src/main/res/xml/fxaccount_authenticator.xml b/mobile/android/services/src/main/res/xml/fxaccount_authenticator.xml
new file mode 100644
index 000000000..7b004e209
--- /dev/null
+++ b/mobile/android/services/src/main/res/xml/fxaccount_authenticator.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<account-authenticator xmlns:android="http://schemas.android.com/apk/res/android"
+    android:accountType="@string/moz_android_shared_fxaccount_type"
+    android:icon="@drawable/icon"
+    android:smallIcon="@drawable/icon"
+    android:label="@string/fxaccount_label"
+    android:accountPreferences="@xml/fxaccount_options" />
diff --git a/mobile/android/services/src/main/res/xml/fxaccount_options.xml b/mobile/android/services/src/main/res/xml/fxaccount_options.xml
new file mode 100644
index 000000000..449fc0545
--- /dev/null
+++ b/mobile/android/services/src/main/res/xml/fxaccount_options.xml
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
+  <PreferenceCategory
+    android:title="@string/fxaccount_options_title" />
+  <PreferenceScreen
+    android:key="options"
+    android:title="@string/fxaccount_options_configure_title">
+    <intent
+      android:action="android.intent.action.MAIN"
+      android:targetPackage="@string/android_package_name_for_ui"
+      android:targetClass="org.mozilla.gecko.fxa.activities.FxAccountStatusActivity">
+    </intent>
+  </PreferenceScreen>
+</PreferenceScreen>
diff --git a/mobile/android/services/src/main/res/xml/fxaccount_status_prefscreen.xml b/mobile/android/services/src/main/res/xml/fxaccount_status_prefscreen.xml
new file mode 100644
index 000000000..570e362cc
--- /dev/null
+++ b/mobile/android/services/src/main/res/xml/fxaccount_status_prefscreen.xml
@@ -0,0 +1,142 @@
+<?xml version="1.0" encoding="utf-8"?>
+<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
+                  xmlns:gecko="http://schemas.android.com/apk/res-auto"
+                  android:key="status_screen">
+
+    <PreferenceCategory
+        android:key="signed_in_as_category"
+        android:title="@string/fxaccount_status_signed_in_as" >
+        <Preference
+            android:editable="false"
+            android:key="profile"
+            android:icon="@drawable/sync_avatar_default"
+            android:persistent="false"
+            android:title="" />
+        <Preference
+            android:editable="false"
+            android:key="manage_account"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_manage_account" />
+        <Preference
+            android:editable="false"
+            android:key="auth_server"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_auth_server" />
+    </PreferenceCategory>
+    <PreferenceCategory
+        android:key="sync_category"
+        android:title="@string/fxaccount_status_sync" >
+        <Preference
+            android:editable="false"
+            android:icon="@drawable/fxaccount_sync_error"
+            android:key="needs_credentials"
+            android:layout="@layout/fxaccount_status_error_preference"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_needs_credentials" />
+        <Preference
+            android:editable="false"
+            android:icon="@drawable/fxaccount_sync_error"
+            android:key="needs_upgrade"
+            android:layout="@layout/fxaccount_status_error_preference"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_needs_upgrade" />
+        <Preference
+            android:editable="false"
+            android:icon="@drawable/fxaccount_sync_error"
+            android:key="needs_verification"
+            android:layout="@layout/fxaccount_status_error_preference"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_needs_verification" />
+        <Preference
+            android:editable="false"
+            android:icon="@drawable/fxaccount_sync_error"
+            android:key="needs_master_sync_automatically_enabled"
+            android:layout="@layout/fxaccount_status_error_preference"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_needs_master_sync_automatically_enabled" />
+        <Preference
+            android:editable="false"
+            android:icon="@drawable/fxaccount_sync_error"
+            android:key="needs_finish_migrating"
+            android:layout="@layout/fxaccount_status_error_preference"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_needs_finish_migrating" />
+
+        <Preference
+            android:editable="false"
+            android:key="sync_now"
+            android:defaultValue=""
+            android:persistent="false"
+            android:title="@string/fxaccount_status_sync_now"
+            android:summary="" />
+
+        <CheckBoxPreference
+            android:key="bookmarks"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_bookmarks" />
+        <CheckBoxPreference
+            android:key="history"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_history" />
+        <CheckBoxPreference
+            android:key="tabs"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_tabs" />
+        <CheckBoxPreference
+            android:key="passwords"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_passwords" />
+
+        <EditTextPreference
+            android:singleLine="true"
+            android:key="device_name"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_device_name" />
+
+        <Preference
+            android:editable="false"
+            android:key="sync_server"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_sync_server" />
+        <org.mozilla.gecko.fxa.activities.CustomColorPreference
+            android:editable="false"
+            android:key="remove_account"
+            android:persistent="false"
+            gecko:titleColor="@color/rejection_red"
+            android:title="@string/fxaccount_remove_account" />
+        <Preference
+            android:editable="false"
+            android:key="more"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_more" />
+
+    </PreferenceCategory>
+    <PreferenceCategory
+        android:key="legal_category"
+        android:title="@string/fxaccount_status_legal" >
+        <Preference
+            android:editable="false"
+            android:key="linktos"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_linktos" />
+        <Preference
+            android:editable="false"
+            android:key="linkprivacy"
+            android:persistent="false"
+            android:title="@string/fxaccount_status_linkprivacy" />
+    </PreferenceCategory>
+    <PreferenceCategory
+        android:key="debug_category" >
+        <Preference android:key="debug_refresh" />
+        <Preference android:key="debug_dump" />
+        <Preference android:key="debug_force_sync" />
+        <Preference android:key="debug_invalidate_certificate" />
+        <Preference android:key="debug_forget_certificate" />
+        <Preference android:key="debug_require_password" />
+        <Preference android:key="debug_require_upgrade" />
+        <Preference android:key="debug_migrated_from_sync11" />
+        <Preference android:key="debug_make_account_stage" />
+        <Preference android:key="debug_make_account_default" />
+	</PreferenceCategory>
+
+</PreferenceScreen>
diff --git a/mobile/android/services/src/main/res/xml/fxaccount_syncadapter.xml b/mobile/android/services/src/main/res/xml/fxaccount_syncadapter.xml
new file mode 100644
index 000000000..761920667
--- /dev/null
+++ b/mobile/android/services/src/main/res/xml/fxaccount_syncadapter.xml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<sync-adapter xmlns:android="http://schemas.android.com/apk/res/android"
+    android:accountType="@string/moz_android_shared_fxaccount_type"
+    android:contentAuthority="@string/content_authority_db_browser"
+    android:isAlwaysSyncable="true"
+    android:supportsUploading="true"
+    android:userVisible="true"
+/>