Merge pull request #898 from MoonchildProductions/Sync-weave

Remove FxA Phase 1

8 files changed, 1137 insertions, 1566 deletions

diff --git a/services/sync/modules/engines/addons.js b/services/sync/modules/engines/addons.js
index 01dab58d1..3081e3e87 100644
--- a/services/sync/modules/engines/addons.js
+++ b/services/sync/modules/engines/addons.js
@@ -25,13 +25,10 @@
  *
  * Synchronization is influenced by the following preferences:
  *
+ *  - services.sync.addons.ignoreRepositoryChecking
  *  - services.sync.addons.ignoreUserEnabledChanges
  *  - services.sync.addons.trustedSourceHostnames
  *
- *  and also influenced by whether addons have repository caching enabled and
- *  whether they allow installation of addons from insecure options (both of
- *  which are themselves influenced by the "extensions." pref branch)
- *
  * See the documentation in services-sync.js for the behavior of these prefs.
  */
 "use strict";
@@ -44,7 +41,6 @@ Cu.import("resource://services-sync/engines.js");
 Cu.import("resource://services-sync/record.js");
 Cu.import("resource://services-sync/util.js");
 Cu.import("resource://services-sync/constants.js");
-Cu.import("resource://services-sync/collection_validator.js");
 Cu.import("resource://services-common/async.js");
 
 Cu.import("resource://gre/modules/Preferences.jsm");
@@ -54,7 +50,7 @@ XPCOMUtils.defineLazyModuleGetter(this, "AddonManager",
 XPCOMUtils.defineLazyModuleGetter(this, "AddonRepository",
                                   "resource://gre/modules/addons/AddonRepository.jsm");
 
-this.EXPORTED_SYMBOLS = ["AddonsEngine", "AddonValidator"];
+this.EXPORTED_SYMBOLS = ["AddonsEngine"];
 
 // 7 days in milliseconds.
 const PRUNE_ADDON_CHANGES_THRESHOLD = 60 * 60 * 24 * 7 * 1000;
@@ -177,7 +173,7 @@ AddonsEngine.prototype = {
           continue;
       }
 
-      if (!this.isAddonSyncable(addons[id])) {
+      if (!this._store.isAddonSyncable(addons[id])) {
         continue;
       }
 
@@ -235,10 +231,6 @@ AddonsEngine.prototype = {
     let cb = Async.makeSpinningCallback();
     this._reconciler.refreshGlobalState(cb);
     cb.wait();
-  },
-
-  isAddonSyncable(addon, ignoreRepoCheck) {
-    return this._store.isAddonSyncable(addon, ignoreRepoCheck);
   }
 };
 
@@ -286,14 +278,6 @@ AddonsStore.prototype = {
       }
     }
 
-    // Ignore incoming records for which an existing non-syncable addon
-    // exists.
-    let existingMeta = this.reconciler.addons[record.addonID];
-    if (existingMeta && !this.isAddonSyncable(existingMeta)) {
-      this._log.info("Ignoring incoming record for an existing but non-syncable addon", record.addonID);
-      return;
-    }
-
     Store.prototype.applyIncoming.call(this, record);
   },
 
@@ -314,14 +298,6 @@ AddonsStore.prototype = {
     // engine and the record will try to be applied later.
     let results = cb.wait();
 
-    if (results.skipped.includes(record.addonID)) {
-      this._log.info("Add-on skipped: " + record.addonID);
-      // Just early-return for skipped addons - we don't want to arrange to
-      // try again next time because the condition that caused up to skip
-      // will remain true for this addon forever.
-      return;
-    }
-
     let addon;
     for (let a of results.addons) {
       if (a.id == record.addonID) {
@@ -499,7 +475,7 @@ AddonsStore.prototype = {
       }
 
       this._log.info("Uninstalling add-on as part of wipe: " + addon.id);
-      Utils.catch.call(this, () => addon.uninstall())();
+      Utils.catch(addon.uninstall)();
     }
   },
 
@@ -538,22 +514,16 @@ AddonsStore.prototype = {
    *
    * @param  addon
    *         Addon instance
-   * @param ignoreRepoCheck
-   *         Should we skip checking the Addons repository (primarially useful
-   *         for testing and validation).
    * @return Boolean indicating whether it is appropriate for Sync
    */
-  isAddonSyncable: function isAddonSyncable(addon, ignoreRepoCheck = false) {
+  isAddonSyncable: function isAddonSyncable(addon) {
     // Currently, we limit syncable add-ons to those that are:
     //   1) In a well-defined set of types
     //   2) Installed in the current profile
     //   3) Not installed by a foreign entity (i.e. installed by the app)
     //      since they act like global extensions.
     //   4) Is not a hotfix.
-    //   5) The addons XPIProvider doesn't veto it (i.e not being installed in
-    //      the profile directory, or any other reasons it says the addon can't
-    //      be synced)
-    //   6) Are installed from AMO
+    //   5) Are installed from AMO
 
     // We could represent the test as a complex boolean expression. We go the
     // verbose route so the failure reason is logged.
@@ -573,12 +543,6 @@ AddonsStore.prototype = {
       return false;
     }
 
-    // If the addon manager says it's not syncable, we skip it.
-    if (!addon.isSyncable) {
-      this._log.debug(addon.id + " not syncable: vetoed by the addon manager.");
-      return false;
-    }
-
     // This may be too aggressive. If an add-on is downloaded from AMO and
     // manually placed in the profile directory, foreignInstall will be set.
     // Arguably, that add-on should be syncable.
@@ -589,20 +553,15 @@ AddonsStore.prototype = {
     }
 
     // Ignore hotfix extensions (bug 741670). The pref may not be defined.
-    // XXX - note that addon.isSyncable will be false for hotfix addons, so
-    // this check isn't strictly necessary - except for Sync tests which aren't
-    // setup to create a "real" hotfix addon. This can be removed once those
-    // tests are fixed (but keeping it doesn't hurt either)
     if (this._extensionsPrefs.get("hotfix.id", null) == addon.id) {
       this._log.debug(addon.id + " not syncable: is a hotfix.");
       return false;
     }
 
-    // If the AddonRepository's cache isn't enabled (which it typically isn't
-    // in tests), getCachedAddonByID always returns null - so skip the check
-    // in that case. We also provide a way to specifically opt-out of the check
-    // even if the cache is enabled, which is used by the validators.
-    if (ignoreRepoCheck || !AddonRepository.cacheEnabled) {
+    // We provide a back door to skip the repository checking of an add-on.
+    // This is utilized by the tests to make testing easier. Users could enable
+    // this, but it would sacrifice security.
+    if (Svc.Prefs.get("addons.ignoreRepositoryChecking", false)) {
       return true;
     }
 
@@ -745,69 +704,3 @@ AddonsTracker.prototype = {
     this.reconciler.stopListening();
   },
 };
-
-class AddonValidator extends CollectionValidator {
-  constructor(engine = null) {
-    super("addons", "id", [
-      "addonID",
-      "enabled",
-      "applicationID",
-      "source"
-    ]);
-    this.engine = engine;
-  }
-
-  getClientItems() {
-    return Promise.all([
-      new Promise(resolve =>
-        AddonManager.getAllAddons(resolve)),
-      new Promise(resolve =>
-        AddonManager.getAddonsWithOperationsByTypes(["extension", "theme"], resolve)),
-    ]).then(([installed, addonsWithPendingOperation]) => {
-      // Addons pending install won't be in the first list, but addons pending
-      // uninstall/enable/disable will be in both lists.
-      let all = new Map(installed.map(addon => [addon.id, addon]));
-      for (let addon of addonsWithPendingOperation) {
-        all.set(addon.id, addon);
-      }
-      // Convert to an array since Map.prototype.values returns an iterable
-      return [...all.values()];
-    });
-  }
-
-  normalizeClientItem(item) {
-    let enabled = !item.userDisabled;
-    if (item.pendingOperations & AddonManager.PENDING_ENABLE) {
-      enabled = true;
-    } else if (item.pendingOperations & AddonManager.PENDING_DISABLE) {
-      enabled = false;
-    }
-    return {
-      enabled,
-      id: item.syncGUID,
-      addonID: item.id,
-      applicationID: Services.appinfo.ID,
-      source: "amo", // check item.foreignInstall?
-      original: item
-    };
-  }
-
-  normalizeServerItem(item) {
-    let guid = this.engine._findDupe(item);
-    if (guid) {
-      item.id = guid;
-    }
-    return item;
-  }
-
-  clientUnderstands(item) {
-    return item.applicationID === Services.appinfo.ID;
-  }
-
-  syncedByClient(item) {
-    return !item.original.hidden &&
-           !item.original.isSystem &&
-           !(item.original.pendingOperations & AddonManager.PENDING_UNINSTALL) &&
-           this.engine.isAddonSyncable(item.original, true);
-  }
-}
diff --git a/services/sync/modules/engines/bookmarks.js b/services/sync/modules/engines/bookmarks.js
index 76a198a8b..41283c06d 100644
--- a/services/sync/modules/engines/bookmarks.js
+++ b/services/sync/modules/engines/bookmarks.js
@@ -11,7 +11,6 @@ var Ci = Components.interfaces;
 var Cu = Components.utils;
 
 Cu.import("resource://gre/modules/PlacesUtils.jsm");
-Cu.import("resource://gre/modules/PlacesSyncUtils.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://services-common/async.js");
 Cu.import("resource://services-sync/constants.js");
@@ -20,57 +19,21 @@ Cu.import("resource://services-sync/record.js");
 Cu.import("resource://services-sync/util.js");
 Cu.import("resource://gre/modules/Task.jsm");
 Cu.import("resource://gre/modules/PlacesBackups.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "BookmarkValidator",
-                                  "resource://services-sync/bookmark_validator.js");
-XPCOMUtils.defineLazyGetter(this, "PlacesBundle", () => {
-  let bundleService = Cc["@mozilla.org/intl/stringbundle;1"]
-                        .getService(Ci.nsIStringBundleService);
-  return bundleService.createBundle("chrome://places/locale/places.properties");
-});
-
-const ANNOS_TO_TRACK = [PlacesSyncUtils.bookmarks.DESCRIPTION_ANNO,
-                        PlacesSyncUtils.bookmarks.SIDEBAR_ANNO,
+
+const ALLBOOKMARKS_ANNO    = "AllBookmarks";
+const DESCRIPTION_ANNO     = "bookmarkProperties/description";
+const SIDEBAR_ANNO         = "bookmarkProperties/loadInSidebar";
+const MOBILEROOT_ANNO      = "mobile/bookmarksRoot";
+const MOBILE_ANNO          = "MobileBookmarks";
+const EXCLUDEBACKUP_ANNO   = "places/excludeFromBackup";
+const SMART_BOOKMARKS_ANNO = "Places/SmartBookmark";
+const PARENT_ANNO          = "sync/parent";
+const ORGANIZERQUERY_ANNO  = "PlacesOrganizer/OrganizerQuery";
+const ANNOS_TO_TRACK = [DESCRIPTION_ANNO, SIDEBAR_ANNO,
                         PlacesUtils.LMANNO_FEEDURI, PlacesUtils.LMANNO_SITEURI];
 
 const SERVICE_NOT_SUPPORTED = "Service not supported on this platform";
 const FOLDER_SORTINDEX = 1000000;
-const {
-  SOURCE_SYNC,
-  SOURCE_IMPORT,
-  SOURCE_IMPORT_REPLACE,
-} = Ci.nsINavBookmarksService;
-
-const SQLITE_MAX_VARIABLE_NUMBER = 999;
-
-const ORGANIZERQUERY_ANNO = "PlacesOrganizer/OrganizerQuery";
-const ALLBOOKMARKS_ANNO = "AllBookmarks";
-const MOBILE_ANNO = "MobileBookmarks";
-
-// The tracker ignores changes made by bookmark import and restore, and
-// changes made by Sync. We don't need to exclude `SOURCE_IMPORT`, but both
-// import and restore fire `bookmarks-restore-*` observer notifications, and
-// the tracker doesn't currently distinguish between the two.
-const IGNORED_SOURCES = [SOURCE_SYNC, SOURCE_IMPORT, SOURCE_IMPORT_REPLACE];
-
-// Returns the constructor for a bookmark record type.
-function getTypeObject(type) {
-  switch (type) {
-    case "bookmark":
-    case "microsummary":
-      return Bookmark;
-    case "query":
-      return BookmarkQuery;
-    case "folder":
-      return BookmarkFolder;
-    case "livemark":
-      return Livemark;
-    case "separator":
-      return BookmarkSeparator;
-    case "item":
-      return PlacesItem;
-  }
-  return null;
-}
 
 this.PlacesItem = function PlacesItem(collection, id, type) {
   CryptoWrapper.call(this, collection, id);
@@ -89,32 +52,26 @@ PlacesItem.prototype = {
   },
 
   getTypeObject: function PlacesItem_getTypeObject(type) {
-    let recordObj = getTypeObject(type);
-    if (!recordObj) {
-      throw new Error("Unknown places item object type: " + type);
+    switch (type) {
+      case "bookmark":
+      case "microsummary":
+        return Bookmark;
+      case "query":
+        return BookmarkQuery;
+      case "folder":
+        return BookmarkFolder;
+      case "livemark":
+        return Livemark;
+      case "separator":
+        return BookmarkSeparator;
+      case "item":
+        return PlacesItem;
     }
-    return recordObj;
+    throw "Unknown places item object type: " + type;
   },
 
   __proto__: CryptoWrapper.prototype,
   _logName: "Sync.Record.PlacesItem",
-
-  // Converts the record to a Sync bookmark object that can be passed to
-  // `PlacesSyncUtils.bookmarks.{insert, update}`.
-  toSyncBookmark() {
-    return {
-      kind: this.type,
-      syncId: this.id,
-      parentSyncId: this.parentid,
-    };
-  },
-
-  // Populates the record from a Sync bookmark object returned from
-  // `PlacesSyncUtils.bookmarks.fetch`.
-  fromSyncBookmark(item) {
-    this.parentid = item.parentSyncId;
-    this.parentName = item.parentTitle;
-  },
 };
 
 Utils.deferGetSet(PlacesItem,
@@ -127,27 +84,6 @@ this.Bookmark = function Bookmark(collection, id, type) {
 Bookmark.prototype = {
   __proto__: PlacesItem.prototype,
   _logName: "Sync.Record.Bookmark",
-
-  toSyncBookmark() {
-    let info = PlacesItem.prototype.toSyncBookmark.call(this);
-    info.title = this.title;
-    info.url = this.bmkUri;
-    info.description = this.description;
-    info.loadInSidebar = this.loadInSidebar;
-    info.tags = this.tags;
-    info.keyword = this.keyword;
-    return info;
-  },
-
-  fromSyncBookmark(item) {
-    PlacesItem.prototype.fromSyncBookmark.call(this, item);
-    this.title = item.title;
-    this.bmkUri = item.url.href;
-    this.description = item.description;
-    this.loadInSidebar = item.loadInSidebar;
-    this.tags = item.tags;
-    this.keyword = item.keyword;
-  },
 };
 
 Utils.deferGetSet(Bookmark,
@@ -161,19 +97,6 @@ this.BookmarkQuery = function BookmarkQuery(collection, id) {
 BookmarkQuery.prototype = {
   __proto__: Bookmark.prototype,
   _logName: "Sync.Record.BookmarkQuery",
-
-  toSyncBookmark() {
-    let info = Bookmark.prototype.toSyncBookmark.call(this);
-    info.folder = this.folderName;
-    info.query = this.queryId;
-    return info;
-  },
-
-  fromSyncBookmark(item) {
-    Bookmark.prototype.fromSyncBookmark.call(this, item);
-    this.folderName = item.folder;
-    this.queryId = item.query;
-  },
 };
 
 Utils.deferGetSet(BookmarkQuery,
@@ -186,20 +109,6 @@ this.BookmarkFolder = function BookmarkFolder(collection, id, type) {
 BookmarkFolder.prototype = {
   __proto__: PlacesItem.prototype,
   _logName: "Sync.Record.Folder",
-
-  toSyncBookmark() {
-    let info = PlacesItem.prototype.toSyncBookmark.call(this);
-    info.description = this.description;
-    info.title = this.title;
-    return info;
-  },
-
-  fromSyncBookmark(item) {
-    PlacesItem.prototype.fromSyncBookmark.call(this, item);
-    this.title = item.title;
-    this.description = item.description;
-    this.children = item.childSyncIds;
-  },
 };
 
 Utils.deferGetSet(BookmarkFolder, "cleartext", ["description", "title",
@@ -211,21 +120,6 @@ this.Livemark = function Livemark(collection, id) {
 Livemark.prototype = {
   __proto__: BookmarkFolder.prototype,
   _logName: "Sync.Record.Livemark",
-
-  toSyncBookmark() {
-    let info = BookmarkFolder.prototype.toSyncBookmark.call(this);
-    info.feed = this.feedUri;
-    info.site = this.siteUri;
-    return info;
-  },
-
-  fromSyncBookmark(item) {
-    BookmarkFolder.prototype.fromSyncBookmark.call(this, item);
-    this.feedUri = item.feed.href;
-    if (item.site) {
-      this.siteUri = item.site.href;
-    }
-  },
 };
 
 Utils.deferGetSet(Livemark, "cleartext", ["siteUri", "feedUri"]);
@@ -236,15 +130,81 @@ this.BookmarkSeparator = function BookmarkSeparator(collection, id) {
 BookmarkSeparator.prototype = {
   __proto__: PlacesItem.prototype,
   _logName: "Sync.Record.Separator",
-
-  fromSyncBookmark(item) {
-    PlacesItem.prototype.fromSyncBookmark.call(this, item);
-    this.pos = item.index;
-  },
 };
 
 Utils.deferGetSet(BookmarkSeparator, "cleartext", "pos");
 
+
+let kSpecialIds = {
+
+  // Special IDs. Note that mobile can attempt to create a record on
+  // dereference; special accessors are provided to prevent recursion within
+  // observers.
+  guids: ["menu", "places", "tags", "toolbar", "unfiled", "mobile"],
+
+  // Create the special mobile folder to store mobile bookmarks.
+  createMobileRoot: function createMobileRoot() {
+    let root = PlacesUtils.placesRootId;
+    let mRoot = PlacesUtils.bookmarks.createFolder(root, "mobile", -1);
+    PlacesUtils.annotations.setItemAnnotation(
+      mRoot, MOBILEROOT_ANNO, 1, 0, PlacesUtils.annotations.EXPIRE_NEVER);
+    PlacesUtils.annotations.setItemAnnotation(
+      mRoot, EXCLUDEBACKUP_ANNO, 1, 0, PlacesUtils.annotations.EXPIRE_NEVER);
+    return mRoot;
+  },
+
+  findMobileRoot: function findMobileRoot(create) {
+    // Use the (one) mobile root if it already exists.
+    let root = PlacesUtils.annotations.getItemsWithAnnotation(MOBILEROOT_ANNO, {});
+    if (root.length != 0)
+      return root[0];
+
+    if (create)
+      return this.createMobileRoot();
+
+    return null;
+  },
+
+  // Accessors for IDs.
+  isSpecialGUID: function isSpecialGUID(g) {
+    return this.guids.indexOf(g) != -1;
+  },
+
+  specialIdForGUID: function specialIdForGUID(guid, create) {
+    if (guid == "mobile") {
+      return this.findMobileRoot(create);
+    }
+    return this[guid];
+  },
+
+  // Don't bother creating mobile: if it doesn't exist, this ID can't be it!
+  specialGUIDForId: function specialGUIDForId(id) {
+    for each (let guid in this.guids)
+      if (this.specialIdForGUID(guid, false) == id)
+        return guid;
+    return null;
+  },
+
+  get menu() {
+    return PlacesUtils.bookmarksMenuFolderId;
+  },
+  get places() {
+    return PlacesUtils.placesRootId;
+  },
+  get tags() {
+    return PlacesUtils.tagsFolderId;
+  },
+  get toolbar() {
+    return PlacesUtils.toolbarFolderId;
+  },
+  get unfiled() {
+    return PlacesUtils.unfiledBookmarksFolderId;
+  },
+  get mobile() {
+    return this.findMobileRoot(true);
+  },
+};
+
 this.BookmarksEngine = function BookmarksEngine(service) {
   SyncEngine.call(this, "Bookmarks", service);
 }
@@ -257,103 +217,68 @@ BookmarksEngine.prototype = {
   _defaultSort: "index",
 
   syncPriority: 4,
-  allowSkippedRecord: false,
-
-  // A diagnostic helper to get the string value for a bookmark's URL given
-  // its ID. Always returns a string - on error will return a string in the
-  // form of "<description of error>" as this is purely for, eg, logging.
-  // (This means hitting the DB directly and we don't bother using a cached
-  // statement - we should rarely hit this.)
-  _getStringUrlForId(id) {
-    let url;
-    try {
-      let stmt = this._store._getStmt(`
-            SELECT h.url
-            FROM moz_places h
-            JOIN moz_bookmarks b ON h.id = b.fk
-            WHERE b.id = :id`);
-      stmt.params.id = id;
-      let rows = Async.querySpinningly(stmt, ["url"]);
-      url = rows.length == 0 ? "<not found>" : rows[0].url;
-    } catch (ex) {
-      if (Async.isShutdownException(ex)) {
-        throw ex;
-      }
-      if (ex instanceof Ci.mozIStorageError) {
-        url = `<failed: Storage error: ${ex.message} (${ex.result})>`;
-      } else {
-        url = `<failed: ${ex.toString()}>`;
-      }
-    }
-    return url;
-  },
 
-  _guidMapFailed: false,
-  _buildGUIDMap: function _buildGUIDMap() {
-    let store = this._store;
-    let guidMap = {};
-    let tree = Async.promiseSpinningly(PlacesUtils.promiseBookmarksTree("", {
-      includeItemIds: true
-    }));
-    function* walkBookmarksTree(tree, parent=null) {
-      if (tree) {
-        // Skip root node
-        if (parent) {
-          yield [tree, parent];
+  _sync: function _sync() {
+    let engine = this;
+    let batchEx = null;
+
+    // Try running sync in batch mode
+    PlacesUtils.bookmarks.runInBatchMode({
+      runBatched: function wrappedSync() {
+        try {
+          SyncEngine.prototype._sync.call(engine);
         }
-        if (tree.children) {
-          for (let child of tree.children) {
-            store._sleep(0); // avoid jank while looping.
-            yield* walkBookmarksTree(child, tree);
-          }
+        catch(ex) {
+          batchEx = ex;
         }
       }
-    }
+    }, null);
 
-    function* walkBookmarksRoots(tree, rootIDs) {
-      for (let id of rootIDs) {
-        let bookmarkRoot = tree.children.find(child => child.id === id);
-        if (bookmarkRoot === null) {
-          continue;
-        }
-        yield* walkBookmarksTree(bookmarkRoot, tree);
-      }
+    // Expose the exception if something inside the batch failed
+    if (batchEx != null) {
+      throw batchEx;
     }
+  },
 
-    let rootsToWalk = getChangeRootIds();
-
-    for (let [node, parent] of walkBookmarksRoots(tree, rootsToWalk)) {
-      let {guid, id, type: placeType} = node;
-      guid = PlacesSyncUtils.bookmarks.guidToSyncId(guid);
+  _guidMapFailed: false,
+  _buildGUIDMap: function _buildGUIDMap() {
+    let guidMap = {};
+    for (let guid in this._store.getAllIDs()) {
+      // Figure out with which key to store the mapping.
       let key;
-      switch (placeType) {
-        case PlacesUtils.TYPE_X_MOZ_PLACE:
-          // Bookmark
-          let query = null;
-          if (node.annos && node.uri.startsWith("place:")) {
-            query = node.annos.find(({name}) =>
-              name === PlacesSyncUtils.bookmarks.SMART_BOOKMARKS_ANNO);
-          }
-          if (query && query.value) {
-            key = "q" + query.value;
-          } else {
-            key = "b" + node.uri + ":" + (node.title || "");
-          }
+      let id = this._store.idForGUID(guid);
+      switch (PlacesUtils.bookmarks.getItemType(id)) {
+        case PlacesUtils.bookmarks.TYPE_BOOKMARK:
+
+          // Smart bookmarks map to their annotation value.
+          let queryId;
+          try {
+            queryId = PlacesUtils.annotations.getItemAnnotation(
+              id, SMART_BOOKMARKS_ANNO);
+          } catch(ex) {}
+          
+          if (queryId)
+            key = "q" + queryId;
+          else
+            key = "b" + PlacesUtils.bookmarks.getBookmarkURI(id).spec + ":" +
+                  PlacesUtils.bookmarks.getItemTitle(id);
           break;
-        case PlacesUtils.TYPE_X_MOZ_PLACE_CONTAINER:
-          // Folder
-          key = "f" + (node.title || "");
+        case PlacesUtils.bookmarks.TYPE_FOLDER:
+          key = "f" + PlacesUtils.bookmarks.getItemTitle(id);
           break;
-        case PlacesUtils.TYPE_X_MOZ_PLACE_SEPARATOR:
-          // Separator
-          key = "s" + node.index;
+        case PlacesUtils.bookmarks.TYPE_SEPARATOR:
+          key = "s" + PlacesUtils.bookmarks.getItemIndex(id);
           break;
         default:
-          this._log.error("Unknown place type: '"+placeType+"'");
           continue;
       }
 
-      let parentName = parent.title || "";
+      // The mapping is on a per parent-folder-name basis.
+      let parent = PlacesUtils.bookmarks.getFolderIdForItem(id);
+      if (parent <= 0)
+        continue;
+
+      let parentName = PlacesUtils.bookmarks.getItemTitle(parent);
       if (guidMap[parentName] == null)
         guidMap[parentName] = {};
 
@@ -381,17 +306,17 @@ BookmarksEngine.prototype = {
         // hack should get them to dupe correctly.
         if (item.queryId) {
           key = "q" + item.queryId;
-          altKey = "b" + item.bmkUri + ":" + (item.title || "");
+          altKey = "b" + item.bmkUri + ":" + item.title;
           break;
         }
         // No queryID? Fall through to the regular bookmark case.
       case "bookmark":
       case "microsummary":
-        key = "b" + item.bmkUri + ":" + (item.title || "");
+        key = "b" + item.bmkUri + ":" + item.title;
         break;
       case "folder":
       case "livemark":
-        key = "f" + (item.title || "");
+        key = "f" + item.title;
         break;
       case "separator":
         key = "s" + item.pos;
@@ -405,22 +330,21 @@ BookmarksEngine.prototype = {
     let guidMap = this._guidMap;
 
     // Give the GUID if we have the matching pair.
-    let parentName = item.parentName || "";
-    this._log.trace("Finding mapping: " + parentName + ", " + key);
-    let parent = guidMap[parentName];
-
+    this._log.trace("Finding mapping: " + item.parentName + ", " + key);
+    let parent = guidMap[item.parentName];
+    
     if (!parent) {
       this._log.trace("No parent => no dupe.");
       return undefined;
     }
-
+      
     let dupe = parent[key];
-
+    
     if (dupe) {
       this._log.trace("Mapped dupe: " + dupe);
       return dupe;
     }
-
+    
     if (altKey) {
       dupe = parent[altKey];
       if (dupe) {
@@ -428,7 +352,7 @@ BookmarksEngine.prototype = {
         return dupe;
       }
     }
-
+    
     this._log.trace("No dupe found for key " + key + "/" + altKey + ".");
     return undefined;
   },
@@ -437,7 +361,7 @@ BookmarksEngine.prototype = {
     SyncEngine.prototype._syncStartup.call(this);
 
     let cb = Async.makeSpinningCallback();
-    Task.spawn(function* () {
+    Task.spawn(function() {
       // For first-syncs, make a backup for the user to restore
       if (this.lastSync == 0) {
         this._log.debug("Bookmarks backup starting.");
@@ -449,7 +373,7 @@ BookmarksEngine.prototype = {
         // Failure to create a backup is somewhat bad, but probably not bad
         // enough to prevent syncing of bookmarks - so just log the error and
         // continue.
-        this._log.warn("Error while backing up bookmarks, but continuing with sync", ex);
+        this._log.warn("Got exception backing up bookmarks, but continuing with sync.", ex);
         cb();
       }
     );
@@ -464,10 +388,8 @@ BookmarksEngine.prototype = {
       try {
         guidMap = this._buildGUIDMap();
       } catch (ex) {
-        if (Async.isShutdownException(ex)) {
-          throw ex;
-        }
-        this._log.warn("Error while building GUID map, skipping all other incoming items", ex);
+        this._log.warn("Got exception building GUID map." +
+                       " Skipping all other incoming items.", ex);
         throw {code: Engine.prototype.eEngineAbortApplyIncoming,
                cause: ex};
       }
@@ -476,71 +398,17 @@ BookmarksEngine.prototype = {
     });
 
     this._store._childrenToOrder = {};
-    this._store.clearPendingDeletions();
-  },
-
-  _deletePending() {
-    // Delete pending items -- See the comment above BookmarkStore's deletePending
-    let newlyModified = Async.promiseSpinningly(this._store.deletePending());
-    let now = this._tracker._now();
-    this._log.debug("Deleted pending items", newlyModified);
-    for (let modifiedSyncID of newlyModified) {
-      if (!this._modified.has(modifiedSyncID)) {
-        this._modified.set(modifiedSyncID, { timestamp: now, deleted: false });
-      }
-    }
-  },
-
-  // We avoid reviving folders since reviving them properly would require
-  // reviving their children as well. Unfortunately, this is the wrong choice
-  // in the case of a bookmark restore where wipeServer failed -- if the
-  // server has the folder as deleted, we *would* want to reupload this folder.
-  // This is mitigated by the fact that we move any undeleted children to the
-  // grandparent when deleting the parent.
-  _shouldReviveRemotelyDeletedRecord(item) {
-    let kind = Async.promiseSpinningly(
-      PlacesSyncUtils.bookmarks.getKindForSyncId(item.id));
-    if (kind === PlacesSyncUtils.bookmarks.KINDS.FOLDER) {
-      return false;
-    }
-
-    // In addition to preventing the deletion of this record (handled by the caller),
-    // we need to mark the parent of this record for uploading next sync, in order
-    // to ensure its children array is accurate.
-    let modifiedTimestamp = this._modified.getModifiedTimestamp(item.id);
-    if (!modifiedTimestamp) {
-      // We only expect this to be called with items locally modified, so
-      // something strange is going on - play it safe and don't revive it.
-      this._log.error("_shouldReviveRemotelyDeletedRecord called on unmodified item: " + item.id);
-      return false;
-    }
-
-    let localID = this._store.idForGUID(item.id);
-    let localParentID = PlacesUtils.bookmarks.getFolderIdForItem(localID);
-    let localParentSyncID = this._store.GUIDForId(localParentID);
-
-    this._log.trace(`Reviving item "${item.id}" and marking parent ${localParentSyncID} as modified.`);
-
-    if (!this._modified.has(localParentSyncID)) {
-      this._modified.set(localParentSyncID, {
-        timestamp: modifiedTimestamp,
-        deleted: false
-      });
-    }
-    return true
   },
 
   _processIncoming: function (newitems) {
     try {
       SyncEngine.prototype._processIncoming.call(this, newitems);
     } finally {
-      try {
-        this._deletePending();
-      } finally {
-        // Reorder children.
-        this._store._orderChildren();
-        delete this._store._childrenToOrder;
-      }
+      // Reorder children.
+      this._tracker.ignoreAll = true;
+      this._store._orderChildren();
+      this._tracker.ignoreAll = false;
+      delete this._store._childrenToOrder;
     }
   },
 
@@ -575,154 +443,16 @@ BookmarksEngine.prototype = {
     }
     let mapped = this._mapDupe(item);
     this._log.debug(item.id + " mapped to " + mapped);
-    // We must return a string, not an object, and the entries in the GUIDMap
-    // are created via "new String()" making them an object.
-    return mapped ? mapped.toString() : mapped;
-  },
-
-  pullAllChanges() {
-    return new BookmarksChangeset(this._store.getAllIDs());
-  },
-
-  pullNewChanges() {
-    let modifiedGUIDs = this._getModifiedGUIDs();
-    if (!modifiedGUIDs.length) {
-      return new BookmarksChangeset(this._tracker.changedIDs);
-    }
-
-    // We don't use `PlacesUtils.promiseDBConnection` here because
-    // `getChangedIDs` might be called while we're in a batch, meaning we
-    // won't see any changes until the batch finishes and the transaction
-    // commits.
-    let db = PlacesUtils.history.QueryInterface(Ci.nsPIPlacesDatabase)
-                        .DBConnection;
-
-    // Filter out tags, organizer queries, and other descendants that we're
-    // not tracking. We chunk `modifiedGUIDs` because SQLite limits the number
-    // of bound parameters per query.
-    for (let startIndex = 0;
-         startIndex < modifiedGUIDs.length;
-         startIndex += SQLITE_MAX_VARIABLE_NUMBER) {
-
-      let chunkLength = Math.min(SQLITE_MAX_VARIABLE_NUMBER,
-                                 modifiedGUIDs.length - startIndex);
-
-      let query = `
-        WITH RECURSIVE
-        modifiedGuids(guid) AS (
-          VALUES ${new Array(chunkLength).fill("(?)").join(", ")}
-        ),
-        syncedItems(id) AS (
-          VALUES ${getChangeRootIds().map(id => `(${id})`).join(", ")}
-          UNION ALL
-          SELECT b.id
-          FROM moz_bookmarks b
-          JOIN syncedItems s ON b.parent = s.id
-        )
-        SELECT b.guid
-        FROM modifiedGuids m
-        JOIN moz_bookmarks b ON b.guid = m.guid
-        LEFT JOIN syncedItems s ON b.id = s.id
-        WHERE s.id IS NULL
-      `;
-
-      let statement = db.createAsyncStatement(query);
-      try {
-        for (let i = 0; i < chunkLength; i++) {
-          statement.bindByIndex(i, modifiedGUIDs[startIndex + i]);
-        }
-        let results = Async.querySpinningly(statement, ["guid"]);
-        for (let { guid } of results) {
-          let syncID = PlacesSyncUtils.bookmarks.guidToSyncId(guid);
-          this._tracker.removeChangedID(syncID);
-        }
-      } finally {
-        statement.finalize();
-      }
-    }
-
-    return new BookmarksChangeset(this._tracker.changedIDs);
-  },
-
-  // Returns an array of Places GUIDs for all changed items. Ignores deletions,
-  // which won't exist in the DB and shouldn't be removed from the tracker.
-  _getModifiedGUIDs() {
-    let guids = [];
-    for (let syncID in this._tracker.changedIDs) {
-      if (this._tracker.changedIDs[syncID].deleted === true) {
-        // The `===` check also filters out old persisted timestamps,
-        // which won't have a `deleted` property.
-        continue;
-      }
-      let guid = PlacesSyncUtils.bookmarks.syncIdToGuid(syncID);
-      guids.push(guid);
-    }
-    return guids;
-  },
-
-  // Called when _findDupe returns a dupe item and the engine has decided to
-  // switch the existing item to the new incoming item.
-  _switchItemToDupe(localDupeGUID, incomingItem) {
-    // We unconditionally change the item's ID in case the engine knows of
-    // an item but doesn't expose it through itemExists. If the API
-    // contract were stronger, this could be changed.
-    this._log.debug("Switching local ID to incoming: " + localDupeGUID + " -> " +
-                    incomingItem.id);
-    this._store.changeItemID(localDupeGUID, incomingItem.id);
-
-    // And mark the parent as being modified. Given we de-dupe based on the
-    // parent *name* it's possible the item having its GUID changed has a
-    // different parent from the incoming record.
-    // So we need to find the GUID of the local parent.
-    let now = this._tracker._now();
-    let localID = this._store.idForGUID(incomingItem.id);
-    let localParentID = PlacesUtils.bookmarks.getFolderIdForItem(localID);
-    let localParentGUID = this._store.GUIDForId(localParentID);
-    this._modified.set(localParentGUID, { modified: now, deleted: false });
-
-    // And we also add the parent as reflected in the incoming record as the
-    // de-dupe process might have used an existing item in a different folder.
-    // But only if the parent exists, otherwise we will upload a deleted item
-    // when it might actually be valid, just unknown to us. Note that this
-    // scenario will still leave us with inconsistent client and server states;
-    // the incoming record on the server references a parent that isn't the
-    // actual parent locally - see bug 1297955.
-    if (localParentGUID != incomingItem.parentid) {
-      let remoteParentID = this._store.idForGUID(incomingItem.parentid);
-      if (remoteParentID > 0) {
-        // The parent specified in the record does exist, so we are going to
-        // attempt a move when we come to applying the record. Mark the parent
-        // as being modified so we will later upload it with the new child
-        // reference.
-        this._modified.set(incomingItem.parentid, { modified: now, deleted: false });
-      } else {
-        // We aren't going to do a move as we don't have the parent (yet?).
-        // When applying the record we will add our special PARENT_ANNO
-        // annotation, so if it arrives in the future (either this Sync or a
-        // later one) it will be reparented.
-        this._log.debug(`Incoming duplicate item ${incomingItem.id} specifies ` +
-                        `non-existing parent ${incomingItem.parentid}`);
-      }
-    }
-
-    // The local, duplicate ID is always deleted on the server - but for
-    // bookmarks it is a logical delete.
-    // Simply adding this (now non-existing) ID to the tracker is enough.
-    this._modified.set(localDupeGUID, { modified: now, deleted: true });
-  },
-  getValidator() {
-    return new BookmarkValidator();
+    return mapped;
   }
 };
 
 function BookmarksStore(name, engine) {
   Store.call(this, name, engine);
-  this._foldersToDelete = new Set();
-  this._atomsToDelete = new Set();
+
   // Explicitly nullify our references to our cached services so we don't leak
   Svc.Obs.add("places-shutdown", function() {
-    for (let query in this._stmts) {
-      let stmt = this._stmts[query];
+    for each (let [query, stmt] in Iterator(this._stmts)) {
       stmt.finalize();
     }
     this._stmts = {};
@@ -732,12 +462,70 @@ BookmarksStore.prototype = {
   __proto__: Store.prototype,
 
   itemExists: function BStore_itemExists(id) {
-    return this.idForGUID(id) > 0;
+    return this.idForGUID(id, true) > 0;
   },
+  
+  /*
+   * If the record is a tag query, rewrite it to refer to the local tag ID.
+   * 
+   * Otherwise, just return.
+   */
+  preprocessTagQuery: function preprocessTagQuery(record) {
+    if (record.type != "query" ||
+        record.bmkUri == null ||
+        !record.folderName)
+      return;
+    
+    // Yes, this works without chopping off the "place:" prefix.
+    let uri           = record.bmkUri
+    let queriesRef    = {};
+    let queryCountRef = {};
+    let optionsRef    = {};
+    PlacesUtils.history.queryStringToQueries(uri, queriesRef, queryCountRef,
+                                             optionsRef);
+    
+    // We only process tag URIs.
+    if (optionsRef.value.resultType != optionsRef.value.RESULTS_AS_TAG_CONTENTS)
+      return;
+    
+    // Tag something to ensure that the tag exists.
+    let tag = record.folderName;
+    let dummyURI = Utils.makeURI("about:weave#BStore_preprocess");
+    PlacesUtils.tagging.tagURI(dummyURI, [tag]);
+
+    // Look for the id of the tag, which might just have been added.
+    let tags = this._getNode(PlacesUtils.tagsFolderId);
+    if (!(tags instanceof Ci.nsINavHistoryQueryResultNode)) {
+      this._log.debug("tags isn't an nsINavHistoryQueryResultNode; aborting.");
+      return;
+    }
 
+    tags.containerOpen = true;
+    try {
+      for (let i = 0; i < tags.childCount; i++) {
+        let child = tags.getChild(i);
+        if (child.title == tag) {
+          // Found the tag, so fix up the query to use the right id.
+          this._log.debug("Tag query folder: " + tag + " = " + child.itemId);
+          
+          this._log.trace("Replacing folders in: " + uri);
+          for each (let q in queriesRef.value)
+            q.setFolders([child.itemId], 1);
+          
+          record.bmkUri = PlacesUtils.history.queriesToQueryString(
+            queriesRef.value, queryCountRef.value, optionsRef.value);
+          return;
+        }
+      }
+    }
+    finally {
+      tags.containerOpen = false;
+    }
+  },
+  
   applyIncoming: function BStore_applyIncoming(record) {
     this._log.debug("Applying record " + record.id);
-    let isSpecial = PlacesSyncUtils.bookmarks.ROOTS.includes(record.id);
+    let isSpecial = record.id in kSpecialIds;
 
     if (record.deleted) {
       if (isSpecial) {
@@ -765,217 +553,548 @@ BookmarksStore.prototype = {
       return;
     }
 
+    // Preprocess the record before doing the normal apply.
+    this.preprocessTagQuery(record);
+
     // Figure out the local id of the parent GUID if available
     let parentGUID = record.parentid;
     if (!parentGUID) {
       throw "Record " + record.id + " has invalid parentid: " + parentGUID;
     }
-    this._log.debug("Remote parent is " + parentGUID);
+    this._log.debug("Local parent is " + parentGUID);
+
+    let parentId = this.idForGUID(parentGUID);
+    if (parentId > 0) {
+      // Save the parent id for modifying the bookmark later
+      record._parent = parentId;
+      record._orphan = false;
+      this._log.debug("Record " + record.id + " is not an orphan.");
+    } else {
+      this._log.trace("Record " + record.id +
+                      " is an orphan: could not find parent " + parentGUID);
+      record._orphan = true;
+    }
 
     // Do the normal processing of incoming records
     Store.prototype.applyIncoming.call(this, record);
 
-    if (record.type == "folder" && record.children) {
-      this._childrenToOrder[record.id] = record.children;
+    // Do some post-processing if we have an item
+    let itemId = this.idForGUID(record.id);
+    if (itemId > 0) {
+      // Move any children that are looking for this folder as a parent
+      if (record.type == "folder") {
+        this._reparentOrphans(itemId);
+        // Reorder children later
+        if (record.children)
+          this._childrenToOrder[record.id] = record.children;
+      }
+
+      // Create an annotation to remember that it needs reparenting.
+      if (record._orphan) {
+        PlacesUtils.annotations.setItemAnnotation(
+          itemId, PARENT_ANNO, parentGUID, 0,
+          PlacesUtils.annotations.EXPIRE_NEVER);
+      }
+    }
+  },
+
+  /**
+   * Find all ids of items that have a given value for an annotation
+   */
+  _findAnnoItems: function BStore__findAnnoItems(anno, val) {
+    return PlacesUtils.annotations.getItemsWithAnnotation(anno, {})
+                      .filter(function(id) {
+      return PlacesUtils.annotations.getItemAnnotation(id, anno) == val;
+    });
+  },
+
+  /**
+   * For the provided parent item, attach its children to it
+   */
+  _reparentOrphans: function _reparentOrphans(parentId) {
+    // Find orphans and reunite with this folder parent
+    let parentGUID = this.GUIDForId(parentId);
+    let orphans = this._findAnnoItems(PARENT_ANNO, parentGUID);
+
+    this._log.debug("Reparenting orphans " + orphans + " to " + parentId);
+    orphans.forEach(function(orphan) {
+      // Move the orphan to the parent and drop the missing parent annotation
+      if (this._reparentItem(orphan, parentId)) {
+        PlacesUtils.annotations.removeItemAnnotation(orphan, PARENT_ANNO);
+      }
+    }, this);
+  },
+
+  _reparentItem: function _reparentItem(itemId, parentId) {
+    this._log.trace("Attempting to move item " + itemId + " to new parent " +
+                    parentId);
+    try {
+      if (parentId > 0) {
+        PlacesUtils.bookmarks.moveItem(itemId, parentId,
+                                       PlacesUtils.bookmarks.DEFAULT_INDEX);
+        return true;
+      }
+    } catch(ex) {
+      this._log.debug("Failed to reparent item. ", ex);
+    }
+    return false;
+  },
+
+  // Turn a record's nsINavBookmarksService constant and other attributes into
+  // a granular type for comparison.
+  _recordType: function _recordType(itemId) {
+    let bms  = PlacesUtils.bookmarks;
+    let type = bms.getItemType(itemId);
+
+    switch (type) {
+      case bms.TYPE_FOLDER:
+        if (PlacesUtils.annotations
+                       .itemHasAnnotation(itemId, PlacesUtils.LMANNO_FEEDURI)) {
+          return "livemark";
+        }
+        return "folder";
+
+      case bms.TYPE_BOOKMARK:
+        let bmkUri = bms.getBookmarkURI(itemId).spec;
+        if (bmkUri.indexOf("place:") == 0) {
+          return "query";
+        }
+        return "bookmark";
+
+      case bms.TYPE_SEPARATOR:
+        return "separator";
+
+      default:
+        return null;
     }
   },
 
   create: function BStore_create(record) {
-    let info = record.toSyncBookmark();
-    // This can throw if we're inserting an invalid or incomplete bookmark.
-    // That's fine; the exception will be caught by `applyIncomingBatch`
-    // without aborting further processing.
-    let item = Async.promiseSpinningly(PlacesSyncUtils.bookmarks.insert(info));
-    if (item) {
-      this._log.debug(`Created ${item.kind} ${item.syncId} under ${
-        item.parentSyncId}`, item);
+    // Default to unfiled if we don't have the parent yet.
+    
+    // Valid parent IDs are all positive integers. Other values -- undefined,
+    // null, -1 -- all compare false for > 0, so this catches them all. We
+    // don't just use <= without the !, because undefined and null compare
+    // false for that, too!
+    if (!(record._parent > 0)) {
+      this._log.debug("Parent is " + record._parent + "; reparenting to unfiled.");
+      record._parent = kSpecialIds.unfiled;
+    }
+
+    let newId;
+    switch (record.type) {
+    case "bookmark":
+    case "query":
+    case "microsummary": {
+      let uri = Utils.makeURI(record.bmkUri);
+      newId = PlacesUtils.bookmarks.insertBookmark(
+        record._parent, uri, PlacesUtils.bookmarks.DEFAULT_INDEX, record.title);
+      this._log.debug("created bookmark " + newId + " under " + record._parent
+                      + " as " + record.title + " " + record.bmkUri);
+
+      // Smart bookmark annotations are strings.
+      if (record.queryId) {
+        PlacesUtils.annotations.setItemAnnotation(
+          newId, SMART_BOOKMARKS_ANNO, record.queryId, 0,
+          PlacesUtils.annotations.EXPIRE_NEVER);
+      }
+
+      if (Array.isArray(record.tags)) {
+        this._tagURI(uri, record.tags);
+      }
+      PlacesUtils.bookmarks.setKeywordForBookmark(newId, record.keyword);
+      if (record.description) {
+        PlacesUtils.annotations.setItemAnnotation(
+          newId, DESCRIPTION_ANNO, record.description, 0,
+          PlacesUtils.annotations.EXPIRE_NEVER);
+      }
+
+      if (record.loadInSidebar) {
+        PlacesUtils.annotations.setItemAnnotation(
+          newId, SIDEBAR_ANNO, true, 0,
+          PlacesUtils.annotations.EXPIRE_NEVER);
+      }
+
+    } break;
+    case "folder":
+      newId = PlacesUtils.bookmarks.createFolder(
+        record._parent, record.title, PlacesUtils.bookmarks.DEFAULT_INDEX);
+      this._log.debug("created folder " + newId + " under " + record._parent
+                      + " as " + record.title);
+
+      if (record.description) {
+        PlacesUtils.annotations.setItemAnnotation(
+          newId, DESCRIPTION_ANNO, record.description, 0,
+          PlacesUtils.annotations.EXPIRE_NEVER);
+      }
+
+      // record.children will be dealt with in _orderChildren.
+      break;
+    case "livemark":
+      let siteURI = null;
+      if (!record.feedUri) {
+        this._log.debug("No feed URI: skipping livemark record " + record.id);
+        return;
+      }
+      if (PlacesUtils.annotations
+                     .itemHasAnnotation(record._parent, PlacesUtils.LMANNO_FEEDURI)) {
+        this._log.debug("Invalid parent: skipping livemark record " + record.id);
+        return;
+      }
+
+      if (record.siteUri != null)
+        siteURI = Utils.makeURI(record.siteUri);
+
+      // Until this engine can handle asynchronous error reporting, we need to
+      // detect errors on creation synchronously.
+      let spinningCb = Async.makeSpinningCallback();
+
+      let livemarkObj = {title: record.title,
+                         parentId: record._parent,
+                         index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+                         feedURI: Utils.makeURI(record.feedUri),
+                         siteURI: siteURI,
+                         guid: record.id};
+      PlacesUtils.livemarks.addLivemark(livemarkObj).then(
+        aLivemark => { spinningCb(null, [Components.results.NS_OK, aLivemark]) },
+        () => { spinningCb(null, [Components.results.NS_ERROR_UNEXPECTED, aLivemark]) }
+      );
+
+      let [status, livemark] = spinningCb.wait();
+      if (!Components.isSuccessCode(status)) {
+        throw status;
+      }
+
+      this._log.debug("Created livemark " + livemark.id + " under " +
+                      livemark.parentId + " as " + livemark.title +
+                      ", " + livemark.siteURI.spec + ", " +
+                      livemark.feedURI.spec + ", GUID " +
+                      livemark.guid);
+      break;
+    case "separator":
+      newId = PlacesUtils.bookmarks.insertSeparator(
+        record._parent, PlacesUtils.bookmarks.DEFAULT_INDEX);
+      this._log.debug("created separator " + newId + " under " + record._parent);
+      break;
+    case "item":
+      this._log.debug(" -> got a generic places item.. do nothing?");
+      return;
+    default:
+      this._log.error("_create: Unknown item type: " + record.type);
+      return;
+    }
+
+    if (newId) {
+      // Livemarks can set the GUID through the API, so there's no need to
+      // do that here.
+      this._log.trace("Setting GUID of new item " + newId + " to " + record.id);
+      this._setGUID(newId, record.id);
+    }
+  },
+
+  // Factored out of `remove` to avoid redundant DB queries when the Places ID
+  // is already known.
+  removeById: function removeById(itemId, guid) {
+    let type = PlacesUtils.bookmarks.getItemType(itemId);
+
+    switch (type) {
+    case PlacesUtils.bookmarks.TYPE_BOOKMARK:
+      this._log.debug("  -> removing bookmark " + guid);
+      PlacesUtils.bookmarks.removeItem(itemId);
+      break;
+    case PlacesUtils.bookmarks.TYPE_FOLDER:
+      this._log.debug("  -> removing folder " + guid);
+      PlacesUtils.bookmarks.removeItem(itemId);
+      break;
+    case PlacesUtils.bookmarks.TYPE_SEPARATOR:
+      this._log.debug("  -> removing separator " + guid);
+      PlacesUtils.bookmarks.removeItem(itemId);
+      break;
+    default:
+      this._log.error("remove: Unknown item type: " + type);
+      break;
     }
   },
 
   remove: function BStore_remove(record) {
-    if (PlacesSyncUtils.bookmarks.isRootSyncID(record.id)) {
+    if (kSpecialIds.isSpecialGUID(record.id)) {
       this._log.warn("Refusing to remove special folder " + record.id);
       return;
     }
-    let recordKind = Async.promiseSpinningly(
-      PlacesSyncUtils.bookmarks.getKindForSyncId(record.id));
-    let isFolder = recordKind === PlacesSyncUtils.bookmarks.KINDS.FOLDER;
-    this._log.trace(`Buffering removal of item "${record.id}" of type "${recordKind}".`);
-    if (isFolder) {
-      this._foldersToDelete.add(record.id);
-    } else {
-      this._atomsToDelete.add(record.id);
+
+    let itemId = this.idForGUID(record.id);
+    if (itemId <= 0) {
+      this._log.debug("Item " + record.id + " already removed");
+      return;
     }
+    this.removeById(itemId, record.id);
   },
 
-  update: function BStore_update(record) {
-    let info = record.toSyncBookmark();
-    let item = Async.promiseSpinningly(PlacesSyncUtils.bookmarks.update(info));
-    if (item) {
-      this._log.debug(`Updated ${item.kind} ${item.syncId} under ${
-        item.parentSyncId}`, item);
-    }
+  _taggableTypes: ["bookmark", "microsummary", "query"],
+  isTaggable: function isTaggable(recordType) {
+    return this._taggableTypes.indexOf(recordType) != -1;
   },
 
-  _orderChildren: function _orderChildren() {
-    let promises = Object.keys(this._childrenToOrder).map(syncID => {
-      let children = this._childrenToOrder[syncID];
-      return PlacesSyncUtils.bookmarks.order(syncID, children).catch(ex => {
-        this._log.debug(`Could not order children for ${syncID}`, ex);
-      });
-    });
-    Async.promiseSpinningly(Promise.all(promises));
-  },
-
-  // There's some complexity here around pending deletions. Our goals:
-  //
-  // - Don't delete any bookmarks a user has created but not explicitly deleted
-  //   (This includes any bookmark that was not a child of the folder at the
-  //   time the deletion was recorded, and also bookmarks restored from a backup).
-  // - Don't undelete any bookmark without ensuring the server structure
-  //   includes it (see `BookmarkEngine.prototype._shouldReviveRemotelyDeletedRecord`)
-  //
-  // This leads the following approach:
-  //
-  // - Additions, moves, and updates are processed before deletions.
-  //     - To do this, all deletion operations are buffered during a sync. Folders
-  //       we plan on deleting have their sync id's stored in `this._foldersToDelete`,
-  //       and non-folders we plan on deleting have their sync id's stored in
-  //       `this._atomsToDelete`.
-  //     - The exception to this is the moves that occur to fix the order of bookmark
-  //       children, which are performed after we process deletions.
-  // - Non-folders are deleted before folder deletions, so that when we process
-  //   folder deletions we know the correct state.
-  // - Remote deletions always win for folders, but do not result in recursive
-  //   deletion of children. This is a hack because we're not able to distinguish
-  //   between value changes and structural changes to folders, and we don't even
-  //   have the old server record to compare to. See `BookmarkEngine`'s
-  //   `_shouldReviveRemotelyDeletedRecord` method.
-  // - When a folder is deleted, its remaining children are moved in order to
-  //   their closest living ancestor.  If this is interrupted (unlikely, but
-  //   possible given that we don't perform this operation in a transaction),
-  //   we revive the folder.
-  // - Remote deletions can lose for non-folders, but only until we handle
-  //   bookmark restores correctly (removing stale state from the server -- this
-  //   is to say, if bug 1230011 is fixed, we should never revive bookmarks).
-
-  deletePending: Task.async(function* deletePending() {
-    yield this._deletePendingAtoms();
-    let guidsToUpdate = yield this._deletePendingFolders();
-    this.clearPendingDeletions();
-    return guidsToUpdate;
-  }),
-
-  clearPendingDeletions() {
-    this._foldersToDelete.clear();
-    this._atomsToDelete.clear();
-  },
-
-  _deleteAtom: Task.async(function* _deleteAtom(syncID) {
-    try {
-      let info = yield PlacesSyncUtils.bookmarks.remove(syncID, {
-        preventRemovalOfNonEmptyFolders: true
-      });
-      this._log.trace(`Removed item ${syncID} with type ${info.type}`);
-    } catch (ex) {
-      // Likely already removed.
-      this._log.trace(`Error removing ${syncID}`, ex);
+  update: function BStore_update(record) {
+    let itemId = this.idForGUID(record.id);
+
+    if (itemId <= 0) {
+      this._log.debug("Skipping update for unknown item: " + record.id);
+      return;
     }
-  }),
-
-  _deletePendingAtoms() {
-    return Promise.all(
-      [...this._atomsToDelete.values()]
-        .map(syncID => this._deleteAtom(syncID)));
-  },
-
-  // Returns an array of sync ids that need updates.
-  _deletePendingFolders: Task.async(function* _deletePendingFolders() {
-    // To avoid data loss, we don't want to just delete the folder outright,
-    // so we buffer folder deletions and process them at the end (now).
-    //
-    // At this point, any member in the folder that remains is either a folder
-    // pending deletion (which we'll get to in this function), or an item that
-    // should not be deleted. To avoid deleting these items, we first move them
-    // to the parent of the folder we're about to delete.
-    let needUpdate = new Set();
-    for (let syncId of this._foldersToDelete) {
-      let childSyncIds = yield PlacesSyncUtils.bookmarks.fetchChildSyncIds(syncId);
-      if (!childSyncIds.length) {
-        // No children -- just delete the folder.
-        yield this._deleteAtom(syncId)
-        continue;
-      }
-      // We could avoid some redundant work here by finding the nearest
-      // grandparent who isn't present in `this._toDelete`...
 
-      let grandparentSyncId = this.GUIDForId(
-        PlacesUtils.bookmarks.getFolderIdForItem(
-          this.idForGUID(PlacesSyncUtils.bookmarks.syncIdToGuid(syncId))));
+    // Two items are the same type if they have the same ItemType in Places,
+    // and also share some key characteristics (e.g., both being livemarks).
+    // We figure this out by examining the item to find the equivalent granular
+    // (string) type.
+    // If they're not the same type, we can't just update attributes. Delete
+    // then recreate the record instead.
+    let localItemType    = this._recordType(itemId);
+    let remoteRecordType = record.type;
+    this._log.trace("Local type: " + localItemType + ". " +
+                    "Remote type: " + remoteRecordType + ".");
+
+    if (localItemType != remoteRecordType) {
+      this._log.debug("Local record and remote record differ in type. " +
+                      "Deleting and recreating.");
+      this.removeById(itemId, record.id);
+      this.create(record);
+      return;
+    }
 
-      this._log.trace(`Moving ${childSyncIds.length} children of "${syncId}" to ` +
-                      `grandparent "${grandparentSyncId}" before deletion.`);
+    this._log.trace("Updating " + record.id + " (" + itemId + ")");
 
-      // Move children out of the parent and into the grandparent
-      yield Promise.all(childSyncIds.map(child => PlacesSyncUtils.bookmarks.update({
-        syncId: child,
-        parentSyncId: grandparentSyncId
-      })));
+    // Move the bookmark to a new parent or new position if necessary
+    if (record._parent > 0 &&
+        PlacesUtils.bookmarks.getFolderIdForItem(itemId) != record._parent) {
+      this._reparentItem(itemId, record._parent);
+    }
 
-      // Delete the (now empty) parent
-      try {
-        yield PlacesSyncUtils.bookmarks.remove(syncId, {
-          preventRemovalOfNonEmptyFolders: true
-        });
-      } catch (e) {
-        // We failed, probably because someone added something to this folder
-        // between when we got the children and now (or the database is corrupt,
-        // or something else happened...) This is unlikely, but possible. To
-        // avoid corruption in this case, we need to reupload the record to the
-        // server.
-        //
-        // (Ideally this whole operation would be done in a transaction, and this
-        // wouldn't be possible).
-        needUpdate.add(syncId);
+    for (let [key, val] in Iterator(record.cleartext)) {
+      switch (key) {
+      case "title":
+        PlacesUtils.bookmarks.setItemTitle(itemId, val);
+        break;
+      case "bmkUri":
+        PlacesUtils.bookmarks.changeBookmarkURI(itemId, Utils.makeURI(val));
+        break;
+      case "tags":
+        if (Array.isArray(val)) {
+          if (this.isTaggable(remoteRecordType)) {
+            this._tagID(itemId, val);
+          } else {
+            this._log.debug("Remote record type is invalid for tags: " + remoteRecordType);
+          }
+        }
+        break;
+      case "keyword":
+        PlacesUtils.bookmarks.setKeywordForBookmark(itemId, val);
+        break;
+      case "description":
+        if (val) {
+          PlacesUtils.annotations.setItemAnnotation(
+            itemId, DESCRIPTION_ANNO, val, 0,
+            PlacesUtils.annotations.EXPIRE_NEVER);
+        } else {
+          PlacesUtils.annotations.removeItemAnnotation(itemId, DESCRIPTION_ANNO);
+        }
+        break;
+      case "loadInSidebar":
+        if (val) {
+          PlacesUtils.annotations.setItemAnnotation(
+            itemId, SIDEBAR_ANNO, true, 0,
+            PlacesUtils.annotations.EXPIRE_NEVER);
+        } else {
+          PlacesUtils.annotations.removeItemAnnotation(itemId, SIDEBAR_ANNO);
+        }
+        break;
+      case "queryId":
+        PlacesUtils.annotations.setItemAnnotation(
+          itemId, SMART_BOOKMARKS_ANNO, val, 0,
+          PlacesUtils.annotations.EXPIRE_NEVER);
+        break;
       }
+    }
+  },
 
-      // Add children (for parentid) and grandparent (for children list) to set
-      // of records needing an update, *unless* they're marked for deletion.
-      if (!this._foldersToDelete.has(grandparentSyncId)) {
-        needUpdate.add(grandparentSyncId);
-      }
-      for (let childSyncId of childSyncIds) {
-        if (!this._foldersToDelete.has(childSyncId)) {
-          needUpdate.add(childSyncId);
+  _orderChildren: function _orderChildren() {
+    for (let [guid, children] in Iterator(this._childrenToOrder)) {
+      // Reorder children according to the GUID list. Gracefully deal
+      // with missing items, e.g. locally deleted.
+      let delta = 0;
+      let parent = null;
+      for (let idx = 0; idx < children.length; idx++) {
+        let itemid = this.idForGUID(children[idx]);
+        if (itemid == -1) {
+          delta += 1;
+          this._log.trace("Could not locate record " + children[idx]);
+          continue;
+        }
+        try {
+          // This code path could be optimized by caching the parent earlier.
+          // Doing so should take in count any edge case due to reparenting
+          // or parent invalidations though.
+          if (!parent) {
+            parent = PlacesUtils.bookmarks.getFolderIdForItem(itemid);
+          }
+          PlacesUtils.bookmarks.moveItem(itemid, parent, idx - delta);
+        } catch (ex) {
+          this._log.debug("Could not move item " + children[idx] + ": " + ex);
         }
       }
     }
-    return [...needUpdate];
-  }),
+  },
 
   changeItemID: function BStore_changeItemID(oldID, newID) {
     this._log.debug("Changing GUID " + oldID + " to " + newID);
 
-    Async.promiseSpinningly(PlacesSyncUtils.bookmarks.changeGuid(oldID, newID));
+    // Make sure there's an item to change GUIDs
+    let itemId = this.idForGUID(oldID);
+    if (itemId <= 0)
+      return;
+
+    this._setGUID(itemId, newID);
+  },
+
+  _getNode: function BStore__getNode(folder) {
+    let query = PlacesUtils.history.getNewQuery();
+    query.setFolders([folder], 1);
+    return PlacesUtils.history.executeQuery(
+      query, PlacesUtils.history.getNewQueryOptions()).root;
+  },
+
+  _getTags: function BStore__getTags(uri) {
+    try {
+      if (typeof(uri) == "string")
+        uri = Utils.makeURI(uri);
+    } catch(e) {
+      this._log.warn("Could not parse URI \"" + uri + "\": " + e);
+    }
+    return PlacesUtils.tagging.getTagsForURI(uri, {});
+  },
+
+  _getDescription: function BStore__getDescription(id) {
+    try {
+      return PlacesUtils.annotations.getItemAnnotation(id, DESCRIPTION_ANNO);
+    } catch (e) {
+      return null;
+    }
+  },
+
+  _isLoadInSidebar: function BStore__isLoadInSidebar(id) {
+    return PlacesUtils.annotations.itemHasAnnotation(id, SIDEBAR_ANNO);
+  },
+
+  get _childGUIDsStm() {
+    return this._getStmt(
+      "SELECT id AS item_id, guid " +
+      "FROM moz_bookmarks " +
+      "WHERE parent = :parent " +
+      "ORDER BY position");
+  },
+  _childGUIDsCols: ["item_id", "guid"],
+
+  _getChildGUIDsForId: function _getChildGUIDsForId(itemid) {
+    let stmt = this._childGUIDsStm;
+    stmt.params.parent = itemid;
+    let rows = Async.querySpinningly(stmt, this._childGUIDsCols);
+    return rows.map(function (row) {
+      if (row.guid) {
+        return row.guid;
+      }
+      // A GUID hasn't been assigned to this item yet, do this now.
+      return this.GUIDForId(row.item_id);
+    }, this);
   },
 
   // Create a record starting from the weave id (places guid)
   createRecord: function createRecord(id, collection) {
-    let item = Async.promiseSpinningly(PlacesSyncUtils.bookmarks.fetch(id));
-    if (!item) { // deleted item
-      let record = new PlacesItem(collection, id);
+    let placeId = this.idForGUID(id);
+    let record;
+    if (placeId <= 0) { // deleted item
+      record = new PlacesItem(collection, id);
       record.deleted = true;
       return record;
     }
 
-    let recordObj = getTypeObject(item.kind);
-    if (!recordObj) {
-      this._log.warn("Unknown item type, cannot serialize: " + item.kind);
-      recordObj = PlacesItem;
+    let parent = PlacesUtils.bookmarks.getFolderIdForItem(placeId);
+    switch (PlacesUtils.bookmarks.getItemType(placeId)) {
+    case PlacesUtils.bookmarks.TYPE_BOOKMARK:
+      let bmkUri = PlacesUtils.bookmarks.getBookmarkURI(placeId).spec;
+      if (bmkUri.indexOf("place:") == 0) {
+        record = new BookmarkQuery(collection, id);
+
+        // Get the actual tag name instead of the local itemId
+        let folder = bmkUri.match(/[:&]folder=(\d+)/);
+        try {
+          // There might not be the tag yet when creating on a new client
+          if (folder != null) {
+            folder = folder[1];
+            record.folderName = PlacesUtils.bookmarks.getItemTitle(folder);
+            this._log.trace("query id: " + folder + " = " + record.folderName);
+          }
+        }
+        catch(ex) {}
+        
+        // Persist the Smart Bookmark anno, if found.
+        try {
+          let anno = PlacesUtils.annotations.getItemAnnotation(placeId, SMART_BOOKMARKS_ANNO);
+          if (anno != null) {
+            this._log.trace("query anno: " + SMART_BOOKMARKS_ANNO +
+                            " = " + anno);
+            record.queryId = anno;
+          }
+        }
+        catch(ex) {}
+      }
+      else {
+        record = new Bookmark(collection, id);
+      }
+      record.title = PlacesUtils.bookmarks.getItemTitle(placeId);
+
+      record.parentName = PlacesUtils.bookmarks.getItemTitle(parent);
+      record.bmkUri = bmkUri;
+      record.tags = this._getTags(record.bmkUri);
+      record.keyword = PlacesUtils.bookmarks.getKeywordForBookmark(placeId);
+      record.description = this._getDescription(placeId);
+      record.loadInSidebar = this._isLoadInSidebar(placeId);
+      break;
+
+    case PlacesUtils.bookmarks.TYPE_FOLDER:
+      if (PlacesUtils.annotations
+                     .itemHasAnnotation(placeId, PlacesUtils.LMANNO_FEEDURI)) {
+        record = new Livemark(collection, id);
+        let as = PlacesUtils.annotations;
+        record.feedUri = as.getItemAnnotation(placeId, PlacesUtils.LMANNO_FEEDURI);
+        try {
+          record.siteUri = as.getItemAnnotation(placeId, PlacesUtils.LMANNO_SITEURI);
+        } catch (ex) {}
+      } else {
+        record = new BookmarkFolder(collection, id);
+      }
+
+      if (parent > 0)
+        record.parentName = PlacesUtils.bookmarks.getItemTitle(parent);
+      record.title = PlacesUtils.bookmarks.getItemTitle(placeId);
+      record.description = this._getDescription(placeId);
+      record.children = this._getChildGUIDsForId(placeId);
+      break;
+
+    case PlacesUtils.bookmarks.TYPE_SEPARATOR:
+      record = new BookmarkSeparator(collection, id);
+      if (parent > 0)
+        record.parentName = PlacesUtils.bookmarks.getItemTitle(parent);
+      // Create a positioning identifier for the separator, used by _mapDupe
+      record.pos = PlacesUtils.bookmarks.getItemIndex(placeId);
+      break;
+
+    default:
+      record = new PlacesItem(collection, id);
+      this._log.warn("Unknown item type, cannot serialize: " +
+                     PlacesUtils.bookmarks.getItemType(placeId));
     }
-    let record = new recordObj(collection, id);
-    record.fromSyncBookmark(item);
 
+    record.parentid = this.GUIDForId(parent);
     record.sortindex = this._calculateIndex(record);
 
     return record;
@@ -997,22 +1116,84 @@ BookmarksStore.prototype = {
     return this._getStmt(
         "SELECT frecency " +
         "FROM moz_places " +
-        "WHERE url_hash = hash(:url) AND url = :url " +
+        "WHERE url = :url " +
         "LIMIT 1");
   },
   _frecencyCols: ["frecency"],
 
+  get _setGUIDStm() {
+    return this._getStmt(
+      "UPDATE moz_bookmarks " +
+      "SET guid = :guid " +
+      "WHERE id = :item_id");
+  },
+
+  // Some helper functions to handle GUIDs
+  _setGUID: function _setGUID(id, guid) {
+    if (!guid)
+      guid = Utils.makeGUID();
+
+    let stmt = this._setGUIDStm;
+    stmt.params.guid = guid;
+    stmt.params.item_id = id;
+    Async.querySpinningly(stmt);
+    return guid;
+  },
+
+  get _guidForIdStm() {
+    return this._getStmt(
+      "SELECT guid " +
+      "FROM moz_bookmarks " +
+      "WHERE id = :item_id");
+  },
+  _guidForIdCols: ["guid"],
+
   GUIDForId: function GUIDForId(id) {
-    let guid = Async.promiseSpinningly(PlacesUtils.promiseItemGuid(id));
-    return PlacesSyncUtils.bookmarks.guidToSyncId(guid);
+    let special = kSpecialIds.specialGUIDForId(id);
+    if (special)
+      return special;
+
+    let stmt = this._guidForIdStm;
+    stmt.params.item_id = id;
+
+    // Use the existing GUID if it exists
+    let result = Async.querySpinningly(stmt, this._guidForIdCols)[0];
+    if (result && result.guid)
+      return result.guid;
+
+    // Give the uri a GUID if it doesn't have one
+    return this._setGUID(id);
   },
 
-  idForGUID: function idForGUID(guid) {
-    // guid might be a String object rather than a string.
-    guid = PlacesSyncUtils.bookmarks.syncIdToGuid(guid.toString());
+  get _idForGUIDStm() {
+    return this._getStmt(
+      "SELECT id AS item_id " +
+      "FROM moz_bookmarks " +
+      "WHERE guid = :guid");
+  },
+  _idForGUIDCols: ["item_id"],
+
+  // noCreate is provided as an optional argument to prevent the creation of
+  // non-existent special records, such as "mobile".
+  idForGUID: function idForGUID(guid, noCreate) {
+    if (kSpecialIds.isSpecialGUID(guid))
+      return kSpecialIds.specialIdForGUID(guid, !noCreate);
 
-    return Async.promiseSpinningly(PlacesUtils.promiseItemId(guid).catch(
-      ex => -1));
+    let stmt = this._idForGUIDStm;
+    // guid might be a String object rather than a string.
+    stmt.params.guid = guid.toString();
+
+    let results = Async.querySpinningly(stmt, this._idForGUIDCols);
+    this._log.trace("Number of rows matching GUID " + guid + ": "
+                    + results.length);
+    
+    // Here's the one we care about: the first.
+    let result = results[0];
+    
+    if (!result)
+      return -1;
+    
+    return result.item_id;
   },
 
   _calculateIndex: function _calculateIndex(record) {
@@ -1037,48 +1218,106 @@ BookmarksStore.prototype = {
     return index;
   },
 
-  getAllIDs: function BStore_getAllIDs() {
-    let items = {};
-
-    let query = `
-      WITH RECURSIVE
-      changeRootContents(id) AS (
-        VALUES ${getChangeRootIds().map(id => `(${id})`).join(", ")}
-        UNION ALL
-        SELECT b.id
-        FROM moz_bookmarks b
-        JOIN changeRootContents c ON b.parent = c.id
-      )
-      SELECT guid
-      FROM changeRootContents
-      JOIN moz_bookmarks USING (id)
-    `;
-
-    let statement = this._getStmt(query);
-    let results = Async.querySpinningly(statement, ["guid"]);
-    for (let { guid } of results) {
-      let syncID = PlacesSyncUtils.bookmarks.guidToSyncId(guid);
-      items[syncID] = { modified: 0, deleted: false };
+  _getChildren: function BStore_getChildren(guid, items) {
+    let node = guid; // the recursion case
+    if (typeof(node) == "string") { // callers will give us the guid as the first arg
+      let nodeID = this.idForGUID(guid, true);
+      if (!nodeID) {
+        this._log.debug("No node for GUID " + guid + "; returning no children.");
+        return items;
+      }
+      node = this._getNode(nodeID);
+    }
+    
+    if (node.type == node.RESULT_TYPE_FOLDER) {
+      node.QueryInterface(Ci.nsINavHistoryQueryResultNode);
+      node.containerOpen = true;
+      try {
+        // Remember all the children GUIDs and recursively get more
+        for (let i = 0; i < node.childCount; i++) {
+          let child = node.getChild(i);
+          items[this.GUIDForId(child.itemId)] = true;
+          this._getChildren(child, items);
+        }
+      }
+      finally {
+        node.containerOpen = false;
+      }
     }
 
     return items;
   },
 
+  /**
+   * Associates the URI of the item with the provided ID with the
+   * provided array of tags.
+   * If the provided ID does not identify an item with a URI,
+   * returns immediately.
+   */
+  _tagID: function _tagID(itemID, tags) {
+    if (!itemID || !tags) {
+      return;
+    }
+
+    try {
+      let u = PlacesUtils.bookmarks.getBookmarkURI(itemID);
+      this._tagURI(u, tags);
+    } catch (e) {
+      this._log.warn("Got exception fetching URI for " + itemID + ": not tagging. ", e);
+
+      // I guess it doesn't have a URI. Don't try to tag it.
+      return;
+    }
+  },
+
+  /**
+   * Associate the provided URI with the provided array of tags.
+   * If the provided URI is falsy, returns immediately.
+   */
+  _tagURI: function _tagURI(bookmarkURI, tags) {
+    if (!bookmarkURI || !tags) {
+      return;
+    }
+
+    // Filter out any null/undefined/empty tags.
+    tags = tags.filter(t => t);
+
+    // Temporarily tag a dummy URI to preserve tag ids when untagging.
+    let dummyURI = Utils.makeURI("about:weave#BStore_tagURI");
+    PlacesUtils.tagging.tagURI(dummyURI, tags);
+    PlacesUtils.tagging.untagURI(bookmarkURI, null);
+    PlacesUtils.tagging.tagURI(bookmarkURI, tags);
+    PlacesUtils.tagging.untagURI(dummyURI, null);
+  },
+
+  getAllIDs: function BStore_getAllIDs() {
+    let items = {"menu": true,
+                 "toolbar": true};
+    for each (let guid in kSpecialIds.guids) {
+      if (guid != "places" && guid != "tags")
+        this._getChildren(guid, items);
+    }
+    return items;
+  },
+
   wipe: function BStore_wipe() {
-    this.clearPendingDeletions();
-    Async.promiseSpinningly(Task.spawn(function* () {
+    let cb = Async.makeSpinningCallback();
+    Task.spawn(function() {
       // Save a backup before clearing out all bookmarks.
       yield PlacesBackups.create(null, true);
-      yield PlacesUtils.bookmarks.eraseEverything({
-        source: SOURCE_SYNC,
-      });
-    }));
+      for each (let guid in kSpecialIds.guids)
+        if (guid != "places") {
+          let id = kSpecialIds.specialIdForGUID(guid);
+          if (id)
+            PlacesUtils.bookmarks.removeFolderChildren(id);
+        }
+      cb();
+    });
+    cb.wait();
   }
 };
 
 function BookmarksTracker(name, engine) {
-  this._batchDepth = 0;
-  this._batchSawScoreIncrement = false;
   Tracker.call(this, name, engine);
 
   Svc.Obs.add("places-shutdown", this);
@@ -1086,16 +1325,6 @@ function BookmarksTracker(name, engine) {
 BookmarksTracker.prototype = {
   __proto__: Tracker.prototype,
 
-  //`_ignore` checks the change source for each observer notification, so we
-  // don't want to let the engine ignore all changes during a sync.
-  get ignoreAll() {
-    return false;
-  },
-
-  // Define an empty setter so that the engine doesn't throw a `TypeError`
-  // setting a read-only property.
-  set ignoreAll(value) {},
-
   startTracking: function() {
     PlacesUtils.bookmarks.addObserver(this, true);
     Svc.Obs.add("bookmarks-restore-begin", this);
@@ -1116,9 +1345,11 @@ BookmarksTracker.prototype = {
     switch (topic) {
       case "bookmarks-restore-begin":
         this._log.debug("Ignoring changes from importing bookmarks.");
+        this.ignoreAll = true;
         break;
       case "bookmarks-restore-success":
         this._log.debug("Tracking all items on successful import.");
+        this.ignoreAll = false;
 
         this._log.debug("Restore succeeded: wiping server and other clients.");
         this.engine.service.resetClient([this.name]);
@@ -1127,6 +1358,7 @@ BookmarksTracker.prototype = {
         break;
       case "bookmarks-restore-failed":
         this._log.debug("Tracking all items on failed import.");
+        this.ignoreAll = false;
         break;
     }
   },
@@ -1137,68 +1369,73 @@ BookmarksTracker.prototype = {
     Ci.nsISupportsWeakReference
   ]),
 
-  addChangedID(id, change) {
-    if (!id) {
-      this._log.warn("Attempted to add undefined ID to tracker");
-      return false;
-    }
-    if (this._ignored.includes(id)) {
-      return false;
-    }
-    let shouldSaveChange = false;
-    let currentChange = this.changedIDs[id];
-    if (currentChange) {
-      if (typeof currentChange == "number") {
-        // Allow raw timestamps for backward-compatibility with persisted
-        // changed IDs. The new format uses tuples to track deleted items.
-        shouldSaveChange = currentChange < change.modified;
-      } else {
-        shouldSaveChange = currentChange.modified < change.modified ||
-                           currentChange.deleted != change.deleted;
-      }
-    } else {
-      shouldSaveChange = true;
-    }
-    if (shouldSaveChange) {
-      this._saveChangedID(id, change);
-    }
-    return true;
-  },
-
   /**
    * Add a bookmark GUID to be uploaded and bump up the sync score.
    *
-   * @param itemId
-   *        The Places item ID of the bookmark to upload.
-   * @param guid
-   *        The Places GUID of the bookmark to upload.
-   * @param isTombstone
-   *        Whether we're uploading a tombstone for a removed bookmark.
+   * @param itemGuid
+   *        GUID of the bookmark to upload.
    */
-  _add: function BMT__add(itemId, guid, isTombstone = false) {
-    let syncID = PlacesSyncUtils.bookmarks.guidToSyncId(guid);
-    let info = { modified: Date.now() / 1000, deleted: isTombstone };
-    if (this.addChangedID(syncID, info)) {
+  _add: function BMT__add(itemId, guid) {
+    guid = kSpecialIds.specialGUIDForId(itemId) || guid;
+    if (this.addChangedID(guid))
       this._upScore();
-    }
   },
 
-  /* Every add/remove/change will trigger a sync for MULTI_DEVICE (except in
-     a batch operation, where we do it at the end of the batch) */
+  /* Every add/remove/change will trigger a sync for MULTI_DEVICE. */
   _upScore: function BMT__upScore() {
-    if (this._batchDepth == 0) {
-      this.score += SCORE_INCREMENT_XLARGE;
-    } else {
-      this._batchSawScoreIncrement = true;
+    this.score += SCORE_INCREMENT_XLARGE;
+  },
+
+  /**
+   * Determine if a change should be ignored.
+   *
+   * @param itemId
+   *        Item under consideration to ignore
+   * @param folder (optional)
+   *        Folder of the item being changed
+   */
+  _ignore: function BMT__ignore(itemId, folder, guid) {
+    // Ignore unconditionally if the engine tells us to.
+    if (this.ignoreAll)
+      return true;
+
+    // Get the folder id if we weren't given one.
+    if (folder == null) {
+      try {
+        folder = PlacesUtils.bookmarks.getFolderIdForItem(itemId);
+      } catch (ex) {
+        this._log.debug("getFolderIdForItem(" + itemId +
+                        ") threw; calling _ensureMobileQuery.");
+        // I'm guessing that gFIFI can throw, and perhaps that's why
+        // _ensureMobileQuery is here at all. Try not to call it.
+        this._ensureMobileQuery();
+        folder = PlacesUtils.bookmarks.getFolderIdForItem(itemId);
+      }
+    }
+
+    // Ignore changes to tags (folders under the tags folder).
+    let tags = kSpecialIds.tags;
+    if (folder == tags)
+      return true;
+
+    // Ignore tag items (the actual instance of a tag for a bookmark).
+    if (PlacesUtils.bookmarks.getFolderIdForItem(folder) == tags)
+      return true;
+
+    // Make sure to remove items that have the exclude annotation.
+    if (PlacesUtils.annotations.itemHasAnnotation(itemId, EXCLUDEBACKUP_ANNO)) {
+      this.removeChangedID(guid);
+      return true;
     }
+
+    return false;
   },
 
   onItemAdded: function BMT_onItemAdded(itemId, folder, index,
                                         itemType, uri, title, dateAdded,
-                                        guid, parentGuid, source) {
-    if (IGNORED_SOURCES.includes(source)) {
+                                        guid, parentGuid) {
+    if (this._ignore(itemId, folder, guid))
       return;
-    }
 
     this._log.trace("onItemAdded: " + itemId);
     this._add(itemId, guid);
@@ -1206,51 +1443,13 @@ BookmarksTracker.prototype = {
   },
 
   onItemRemoved: function (itemId, parentId, index, type, uri,
-                           guid, parentGuid, source) {
-    if (IGNORED_SOURCES.includes(source)) {
-      return;
-    }
-
-    // Ignore changes to tags (folders under the tags folder).
-    if (parentId == PlacesUtils.tagsFolderId) {
-      return;
-    }
-
-    let grandParentId = -1;
-    try {
-      grandParentId = PlacesUtils.bookmarks.getFolderIdForItem(parentId);
-    } catch (ex) {
-      // `getFolderIdForItem` can throw if the item no longer exists, such as
-      // when we've removed a subtree using `removeFolderChildren`.
-      return;
-    }
-
-    // Ignore tag items (the actual instance of a tag for a bookmark).
-    if (grandParentId == PlacesUtils.tagsFolderId) {
+                           guid, parentGuid) {
+    if (this._ignore(itemId, parentId, guid)) {
       return;
     }
 
-    /**
-     * The above checks are incomplete: we can still write tombstones for
-     * items that we don't track, and upload extraneous roots.
-     *
-     * Consider the left pane root: it's a child of the Places root, and has
-     * children and grandchildren. `PlacesUIUtils` can create, delete, and
-     * recreate it as needed. We can't determine ancestors when the root or its
-     * children are deleted, because they've already been removed from the
-     * database when `onItemRemoved` is called. Likewise, we can't check their
-     * "exclude from backup" annos, because they've *also* been removed.
-     *
-     * So, we end up writing tombstones for the left pane queries and left
-     * pane root. For good measure, we'll also upload the Places root, because
-     * it's the parent of the left pane root.
-     *
-     * As a workaround, we can track the parent GUID and reconstruct the item's
-     * ancestry at sync time. This is complicated, and the previous behavior was
-     * already wrong, so we'll wait for bug 1258127 to fix this generally.
-     */
     this._log.trace("onItemRemoved: " + itemId);
-    this._add(itemId, guid, /* isTombstone */ true);
+    this._add(itemId, guid);
     this._add(parentId, parentGuid);
   },
 
@@ -1265,40 +1464,32 @@ BookmarksTracker.prototype = {
     if (all.length == 0)
       return;
 
+    // Disable handling of notifications while changing the mobile query
+    this.ignoreAll = true;
+
     let mobile = find(MOBILE_ANNO);
-    let queryURI = Utils.makeURI("place:folder=" + PlacesUtils.mobileFolderId);
-    let title = PlacesBundle.GetStringFromName("MobileBookmarksFolderTitle");
+    let queryURI = Utils.makeURI("place:folder=" + kSpecialIds.mobile);
+    let title = Str.sync.get("mobile.label");
 
     // Don't add OR remove the mobile bookmarks if there's nothing.
-    if (PlacesUtils.bookmarks.getIdForItemAt(PlacesUtils.mobileFolderId, 0) == -1) {
+    if (PlacesUtils.bookmarks.getIdForItemAt(kSpecialIds.mobile, 0) == -1) {
       if (mobile.length != 0)
-        PlacesUtils.bookmarks.removeItem(mobile[0], SOURCE_SYNC);
+        PlacesUtils.bookmarks.removeItem(mobile[0]);
     }
     // Add the mobile bookmarks query if it doesn't exist
     else if (mobile.length == 0) {
-      let query = PlacesUtils.bookmarks.insertBookmark(all[0], queryURI, -1, title, /* guid */ null, SOURCE_SYNC);
+      let query = PlacesUtils.bookmarks.insertBookmark(all[0], queryURI, -1, title);
       PlacesUtils.annotations.setItemAnnotation(query, ORGANIZERQUERY_ANNO, MOBILE_ANNO, 0,
-                                  PlacesUtils.annotations.EXPIRE_NEVER, SOURCE_SYNC);
-      PlacesUtils.annotations.setItemAnnotation(query, PlacesUtils.EXCLUDE_FROM_BACKUP_ANNO, 1, 0,
-                                  PlacesUtils.annotations.EXPIRE_NEVER, SOURCE_SYNC);
+                                  PlacesUtils.annotations.EXPIRE_NEVER);
+      PlacesUtils.annotations.setItemAnnotation(query, EXCLUDEBACKUP_ANNO, 1, 0,
+                                  PlacesUtils.annotations.EXPIRE_NEVER);
     }
-    // Make sure the existing query URL and title are correct
-    else {
-      if (!PlacesUtils.bookmarks.getBookmarkURI(mobile[0]).equals(queryURI)) {
-        PlacesUtils.bookmarks.changeBookmarkURI(mobile[0], queryURI,
-                                                SOURCE_SYNC);
-      }
-      let queryTitle = PlacesUtils.bookmarks.getItemTitle(mobile[0]);
-      if (queryTitle != title) {
-        PlacesUtils.bookmarks.setItemTitle(mobile[0], title, SOURCE_SYNC);
-      }
-      let rootTitle =
-        PlacesUtils.bookmarks.getItemTitle(PlacesUtils.mobileFolderId);
-      if (rootTitle != title) {
-        PlacesUtils.bookmarks.setItemTitle(PlacesUtils.mobileFolderId, title,
-                                           SOURCE_SYNC);
-      }
+    // Make sure the existing title is correct
+    else if (PlacesUtils.bookmarks.getItemTitle(mobile[0]) != title) {
+      PlacesUtils.bookmarks.setItemTitle(mobile[0], title);
     }
+
+    this.ignoreAll = false;
   },
 
   // This method is oddly structured, but the idea is to return as quickly as
@@ -1306,11 +1497,10 @@ BookmarksTracker.prototype = {
   // *each change*.
   onItemChanged: function BMT_onItemChanged(itemId, property, isAnno, value,
                                             lastModified, itemType, parentId,
-                                            guid, parentGuid, oldValue,
-                                            source) {
-    if (IGNORED_SOURCES.includes(source)) {
+                                            guid, parentGuid) {
+    // Quicker checks first.
+    if (this.ignoreAll)
       return;
-    }
 
     if (isAnno && (ANNOS_TO_TRACK.indexOf(property) == -1))
       // Ignore annotations except for the ones that we sync.
@@ -1320,6 +1510,9 @@ BookmarksTracker.prototype = {
     if (property == "favicon")
       return;
 
+    if (this._ignore(itemId, parentId, guid))
+      return;
+
     this._log.trace("onItemChanged: " + itemId +
                     (", " + property + (isAnno? " (anno)" : "")) +
                     (value ? (" = \"" + value + "\"") : ""));
@@ -1328,11 +1521,9 @@ BookmarksTracker.prototype = {
 
   onItemMoved: function BMT_onItemMoved(itemId, oldParent, oldIndex,
                                         newParent, newIndex, itemType,
-                                        guid, oldParentGuid, newParentGuid,
-                                        source) {
-    if (IGNORED_SOURCES.includes(source)) {
+                                        guid, oldParentGuid, newParentGuid) {
+    if (this._ignore(itemId, newParent, guid))
       return;
-    }
 
     this._log.trace("onItemMoved: " + itemId);
     this._add(oldParent, oldParentGuid);
@@ -1342,37 +1533,10 @@ BookmarksTracker.prototype = {
     }
 
     // Remove any position annotations now that the user moved the item
-    PlacesUtils.annotations.removeItemAnnotation(itemId,
-      PlacesSyncUtils.bookmarks.SYNC_PARENT_ANNO, SOURCE_SYNC);
+    PlacesUtils.annotations.removeItemAnnotation(itemId, PARENT_ANNO);
   },
 
-  onBeginUpdateBatch: function () {
-    ++this._batchDepth;
-  },
-  onEndUpdateBatch: function () {
-    if (--this._batchDepth === 0 && this._batchSawScoreIncrement) {
-      this.score += SCORE_INCREMENT_XLARGE;
-      this._batchSawScoreIncrement = false;
-    }
-  },
+  onBeginUpdateBatch: function () {},
+  onEndUpdateBatch: function () {},
   onItemVisited: function () {}
 };
-
-// Returns an array of root IDs to recursively query for synced bookmarks.
-// Items in other roots, including tags and organizer queries, will be
-// ignored.
-function getChangeRootIds() {
-  return [
-    PlacesUtils.bookmarksMenuFolderId,
-    PlacesUtils.toolbarFolderId,
-    PlacesUtils.unfiledBookmarksFolderId,
-    PlacesUtils.mobileFolderId,
-  ];
-}
-
-class BookmarksChangeset extends Changeset {
-  getModifiedTimestamp(id) {
-    let change = this.changes[id];
-    return change ? change.modified : Number.NaN;
-  }
-}
diff --git a/services/sync/modules/engines/clients.js b/services/sync/modules/engines/clients.js
index 3dd679570..6c8e37a7b 100644
--- a/services/sync/modules/engines/clients.js
+++ b/services/sync/modules/engines/clients.js
@@ -2,24 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/**
- * How does the clients engine work?
- *
- * - We use 2 files - commands.json and commands-syncing.json.
- *
- * - At sync upload time, we attempt a rename of commands.json to
- *   commands-syncing.json, and ignore errors (helps for crash during sync!).
- * - We load commands-syncing.json and stash the contents in
- *   _currentlySyncingCommands which lives for the duration of the upload process.
- * - We use _currentlySyncingCommands to build the outgoing records
- * - Immediately after successful upload, we delete commands-syncing.json from
- *   disk (and clear _currentlySyncingCommands). We reconcile our local records
- *   with what we just wrote in the server, and add failed IDs commands
- *   back in commands.json
- * - Any time we need to "save" a command for future syncs, we load
- *   commands.json, update it, and write it back out.
- */
-
 this.EXPORTED_SYMBOLS = [
   "ClientEngine",
   "ClientsRec"
@@ -27,32 +9,17 @@ this.EXPORTED_SYMBOLS = [
 
 var {classes: Cc, interfaces: Ci, utils: Cu} = Components;
 
-Cu.import("resource://services-common/async.js");
 Cu.import("resource://services-common/stringbundle.js");
 Cu.import("resource://services-sync/constants.js");
 Cu.import("resource://services-sync/engines.js");
 Cu.import("resource://services-sync/record.js");
-Cu.import("resource://services-sync/resource.js");
 Cu.import("resource://services-sync/util.js");
-Cu.import("resource://gre/modules/Services.jsm");
-
-XPCOMUtils.defineLazyModuleGetter(this, "fxAccounts",
-  "resource://gre/modules/FxAccounts.jsm");
 
 const CLIENTS_TTL = 1814400; // 21 days
 const CLIENTS_TTL_REFRESH = 604800; // 7 days
-const STALE_CLIENT_REMOTE_AGE = 604800; // 7 days
 
 const SUPPORTED_PROTOCOL_VERSIONS = ["1.1", "1.5"];
 
-function hasDupeCommand(commands, action) {
-  if (!commands) {
-    return false;
-  }
-  return commands.some(other => other.command == action.command &&
-    Utils.deepEquals(other.args, action.args));
-}
-
 this.ClientsRec = function ClientsRec(collection, id) {
   CryptoWrapper.call(this, collection, id);
 }
@@ -66,27 +33,23 @@ Utils.deferGetSet(ClientsRec,
                   "cleartext",
                   ["name", "type", "commands",
                    "version", "protocols",
-                   "formfactor", "os", "appPackage", "application", "device",
-                   "fxaDeviceId"]);
+                   "formfactor", "os", "appPackage", "application", "device"]);
 
 
 this.ClientEngine = function ClientEngine(service) {
   SyncEngine.call(this, "Clients", service);
 
-  // Reset the last sync timestamp on every startup so that we fetch all clients
-  this.resetLastSync();
+  // Reset the client on every startup so that we fetch recent clients
+  this._resetClient();
 }
 ClientEngine.prototype = {
   __proto__: SyncEngine.prototype,
   _storeObj: ClientStore,
   _recordObj: ClientsRec,
   _trackerObj: ClientsTracker,
-  allowSkippedRecord: false,
 
   // Always sync client data as it controls other sync behavior
-  get enabled() {
-    return true;
-  },
+  get enabled() true,
 
   get lastRecordUpload() {
     return Svc.Prefs.get(this.name + ".lastRecordUpload", 0);
@@ -95,20 +58,10 @@ ClientEngine.prototype = {
     Svc.Prefs.set(this.name + ".lastRecordUpload", Math.floor(value));
   },
 
-  get remoteClients() {
-    // return all non-stale clients for external consumption.
-    return Object.values(this._store._remoteClients).filter(v => !v.stale);
-  },
-
-  remoteClientExists(id) {
-    let client = this._store._remoteClients[id];
-    return !!(client && !client.stale);
-  },
-
   // Aggregate some stats on the composition of clients on this account
   get stats() {
     let stats = {
-      hasMobile: this.localType == DEVICE_TYPE_MOBILE,
+      hasMobile: this.localType == "mobile",
       names: [this.localName],
       numClients: 1,
     };
@@ -156,9 +109,7 @@ ClientEngine.prototype = {
     let localID = Svc.Prefs.get("client.GUID", "");
     return localID == "" ? this.localID = Utils.makeGUID() : localID;
   },
-  set localID(value) {
-    Svc.Prefs.set("client.GUID", value);
-  },
+  set localID(value) Svc.Prefs.set("client.GUID", value),
 
   get brandName() {
     let brand = new StringBundle("chrome://branding/locale/brand.properties");
@@ -166,97 +117,23 @@ ClientEngine.prototype = {
   },
 
   get localName() {
-    let name = Utils.getDeviceName();
-    // If `getDeviceName` returns the default name, set the pref. FxA registers
-    // the device before syncing, so we don't need to update the registration
-    // in this case.
-    Svc.Prefs.set("client.name", name);
-    return name;
-  },
-  set localName(value) {
-    Svc.Prefs.set("client.name", value);
-    // Update the registration in the background.
-    fxAccounts.updateDeviceRegistration().catch(error => {
-      this._log.warn("failed to update fxa device registration", error);
-    });
-  },
+    let localName = Svc.Prefs.get("client.name", "");
+    if (localName != "")
+      return localName;
 
-  get localType() {
-    return Utils.getDeviceType();
-  },
-  set localType(value) {
-    Svc.Prefs.set("client.type", value);
+    return this.localName = Utils.getDefaultDeviceName();
   },
+  set localName(value) Svc.Prefs.set("client.name", value),
 
-  getClientName(id) {
-    if (id == this.localID) {
-      return this.localName;
-    }
-    let client = this._store._remoteClients[id];
-    return client ? client.name : "";
-  },
-
-  getClientFxaDeviceId(id) {
-    if (this._store._remoteClients[id]) {
-      return this._store._remoteClients[id].fxaDeviceId;
-    }
-    return null;
-  },
+  get localType() Svc.Prefs.get("client.type", "desktop"),
+  set localType(value) Svc.Prefs.set("client.type", value),
 
   isMobile: function isMobile(id) {
     if (this._store._remoteClients[id])
-      return this._store._remoteClients[id].type == DEVICE_TYPE_MOBILE;
+      return this._store._remoteClients[id].type == "mobile";
     return false;
   },
 
-  _readCommands() {
-    let cb = Async.makeSpinningCallback();
-    Utils.jsonLoad("commands", this, commands => cb(null, commands));
-    return cb.wait() || {};
-  },
-
-  /**
-   * Low level function, do not use directly (use _addClientCommand instead).
-   */
-  _saveCommands(commands) {
-    let cb = Async.makeSpinningCallback();
-    Utils.jsonSave("commands", this, commands, error => {
-      if (error) {
-        this._log.error("Failed to save JSON outgoing commands", error);
-      }
-      cb();
-    });
-    cb.wait();
-  },
-
-  _prepareCommandsForUpload() {
-    let cb = Async.makeSpinningCallback();
-    Utils.jsonMove("commands", "commands-syncing", this).catch(() => {}) // Ignore errors
-      .then(() => {
-        Utils.jsonLoad("commands-syncing", this, commands => cb(null, commands));
-      });
-    return cb.wait() || {};
-  },
-
-  _deleteUploadedCommands() {
-    delete this._currentlySyncingCommands;
-    Async.promiseSpinningly(
-      Utils.jsonRemove("commands-syncing", this).catch(err => {
-        this._log.error("Failed to delete syncing-commands file", err);
-      })
-    );
-  },
-
-  _addClientCommand(clientId, command) {
-    const allCommands = this._readCommands();
-    const clientCommands = allCommands[clientId] || [];
-    if (hasDupeCommand(clientCommands, command)) {
-      return;
-    }
-    allCommands[clientId] = clientCommands.concat(command);
-    this._saveCommands(allCommands);
-  },
-
   _syncStartup: function _syncStartup() {
     // Reupload new client record periodically.
     if (Date.now() / 1000 - this.lastRecordUpload > CLIENTS_TTL_REFRESH) {
@@ -266,157 +143,9 @@ ClientEngine.prototype = {
     SyncEngine.prototype._syncStartup.call(this);
   },
 
-  _processIncoming() {
-    // Fetch all records from the server.
-    this.lastSync = 0;
-    this._incomingClients = {};
-    try {
-      SyncEngine.prototype._processIncoming.call(this);
-      // Since clients are synced unconditionally, any records in the local store
-      // that don't exist on the server must be for disconnected clients. Remove
-      // them, so that we don't upload records with commands for clients that will
-      // never see them. We also do this to filter out stale clients from the
-      // tabs collection, since showing their list of tabs is confusing.
-      for (let id in this._store._remoteClients) {
-        if (!this._incomingClients[id]) {
-          this._log.info(`Removing local state for deleted client ${id}`);
-          this._removeRemoteClient(id);
-        }
-      }
-      // Bug 1264498: Mobile clients don't remove themselves from the clients
-      // collection when the user disconnects Sync, so we mark as stale clients
-      // with the same name that haven't synced in over a week.
-      // (Note we can't simply delete them, or we re-apply them next sync - see
-      // bug 1287687)
-      delete this._incomingClients[this.localID];
-      let names = new Set([this.localName]);
-      for (let id in this._incomingClients) {
-        let record = this._store._remoteClients[id];
-        if (!names.has(record.name)) {
-          names.add(record.name);
-          continue;
-        }
-        let remoteAge = AsyncResource.serverTime - this._incomingClients[id];
-        if (remoteAge > STALE_CLIENT_REMOTE_AGE) {
-          this._log.info(`Hiding stale client ${id} with age ${remoteAge}`);
-          record.stale = true;
-        }
-      }
-    } finally {
-      this._incomingClients = null;
-    }
-  },
-
-  _uploadOutgoing() {
-    this._currentlySyncingCommands = this._prepareCommandsForUpload();
-    const clientWithPendingCommands = Object.keys(this._currentlySyncingCommands);
-    for (let clientId of clientWithPendingCommands) {
-      if (this._store._remoteClients[clientId] || this.localID == clientId) {
-        this._modified.set(clientId, 0);
-      }
-    }
-    SyncEngine.prototype._uploadOutgoing.call(this);
-  },
-
-  _onRecordsWritten(succeeded, failed) {
-    // Reconcile the status of the local records with what we just wrote on the
-    // server
-    for (let id of succeeded) {
-      const commandChanges = this._currentlySyncingCommands[id];
-      if (id == this.localID) {
-        if (this.localCommands) {
-          this.localCommands = this.localCommands.filter(command => !hasDupeCommand(commandChanges, command));
-        }
-      } else {
-        const clientRecord = this._store._remoteClients[id];
-        if (!commandChanges || !clientRecord) {
-          // should be impossible, else we wouldn't have been writing it.
-          this._log.warn("No command/No record changes for a client we uploaded");
-          continue;
-        }
-        // fixup the client record, so our copy of _remoteClients matches what we uploaded.
-        clientRecord.commands = this._store.createRecord(id);
-        // we could do better and pass the reference to the record we just uploaded,
-        // but this will do for now
-      }
-    }
-
-    // Re-add failed commands
-    for (let id of failed) {
-      const commandChanges = this._currentlySyncingCommands[id];
-      if (!commandChanges) {
-        continue;
-      }
-      this._addClientCommand(id, commandChanges);
-    }
-
-    this._deleteUploadedCommands();
-
-    // Notify other devices that their own client collection changed
-    const idsToNotify = succeeded.reduce((acc, id) => {
-      if (id == this.localID) {
-        return acc;
-      }
-      const fxaDeviceId = this.getClientFxaDeviceId(id);
-      return fxaDeviceId ? acc.concat(fxaDeviceId) : acc;
-    }, []);
-    if (idsToNotify.length > 0) {
-      this._notifyCollectionChanged(idsToNotify);
-    }
-  },
-
-  _notifyCollectionChanged(ids) {
-    const message = {
-      version: 1,
-      command: "sync:collection_changed",
-      data: {
-        collections: ["clients"]
-      }
-    };
-    fxAccounts.notifyDevices(ids, message, NOTIFY_TAB_SENT_TTL_SECS);
-  },
-
-  _syncFinish() {
-    // Record histograms for our device types, and also write them to a pref
-    // so non-histogram telemetry (eg, UITelemetry) has easy access to them.
-    for (let [deviceType, count] of this.deviceTypes) {
-      let hid;
-      let prefName = this.name + ".devices.";
-      switch (deviceType) {
-        case "desktop":
-          hid = "WEAVE_DEVICE_COUNT_DESKTOP";
-          prefName += "desktop";
-          break;
-        case "mobile":
-          hid = "WEAVE_DEVICE_COUNT_MOBILE";
-          prefName += "mobile";
-          break;
-        default:
-          this._log.warn(`Unexpected deviceType "${deviceType}" recording device telemetry.`);
-          continue;
-      }
-      Services.telemetry.getHistogramById(hid).add(count);
-      Svc.Prefs.set(prefName, count);
-    }
-    SyncEngine.prototype._syncFinish.call(this);
-  },
-
-  _reconcile: function _reconcile(item) {
-    // Every incoming record is reconciled, so we use this to track the
-    // contents of the collection on the server.
-    this._incomingClients[item.id] = item.modified;
-
-    if (!this._store.itemExists(item.id)) {
-      return true;
-    }
-    // Clients are synced unconditionally, so we'll always have new records.
-    // Unfortunately, this will cause the scheduler to use the immediate sync
-    // interval for the multi-device case, instead of the active interval. We
-    // work around this by updating the record during reconciliation, and
-    // returning false to indicate that the record doesn't need to be applied
-    // later.
-    this._store.update(item);
-    return false;
+  // Always process incoming items because they might have commands
+  _reconcile: function _reconcile() {
+    return true;
   },
 
   // Treat reset the same as wiping for locally cached clients
@@ -426,13 +155,7 @@ ClientEngine.prototype = {
 
   _wipeClient: function _wipeClient() {
     SyncEngine.prototype._resetClient.call(this);
-    delete this.localCommands;
     this._store.wipe();
-    const logRemoveError = err => this._log.warn("Could not delete json file", err);
-    Async.promiseSpinningly(
-      Utils.jsonRemove("commands", this).catch(logRemoveError)
-        .then(Utils.jsonRemove("commands-syncing", this).catch(logRemoveError))
-    );
   },
 
   removeClientData: function removeClientData() {
@@ -471,6 +194,14 @@ ClientEngine.prototype = {
   },
 
   /**
+   * Remove any commands for the local client and mark it for upload.
+   */
+  clearCommands: function clearCommands() {
+    delete this.localCommands;
+    this._tracker.addChangedID(this.localID);
+  },
+
+  /**
    * Sends a command+args pair to a specific client.
    *
    * @param command Command string
@@ -484,17 +215,30 @@ ClientEngine.prototype = {
     if (!client) {
       throw new Error("Unknown remote client ID: '" + clientId + "'.");
     }
-    if (client.stale) {
-      throw new Error("Stale remote client ID: '" + clientId + "'.");
-    }
+
+    // notDupe compares two commands and returns if they are not equal.
+    let notDupe = function(other) {
+      return other.command != command || !Utils.deepEquals(other.args, args);
+    };
 
     let action = {
       command: command,
       args: args,
     };
 
+    if (!client.commands) {
+      client.commands = [action];
+    }
+    // Add the new action if there are no duplicates.
+    else if (client.commands.every(notDupe)) {
+      client.commands.push(action);
+    }
+    // It must be a dupe. Skip.
+    else {
+      return;
+    }
+
     this._log.trace("Client " + clientId + " got a new action: " + [command, args]);
-    this._addClientCommand(clientId, action);
     this._tracker.addChangedID(clientId);
   },
 
@@ -505,17 +249,13 @@ ClientEngine.prototype = {
    */
   processIncomingCommands: function processIncomingCommands() {
     return this._notify("clients:process-commands", "", function() {
-      if (!this.localCommands) {
-        return true;
-      }
+      let commands = this.localCommands;
 
-      const clearedCommands = this._readCommands()[this.localID];
-      const commands = this.localCommands.filter(command => !hasDupeCommand(clearedCommands, command));
+      // Immediately clear out the commands as we've got them locally.
+      this.clearCommands();
 
-      let URIsToDisplay = [];
       // Process each command in order.
-      for (let rawCommand of commands) {
-        let {command, args} = rawCommand;
+      for each (let {command, args} in commands) {
         this._log.debug("Processing command: " + command + "(" + args + ")");
 
         let engines = [args[0]];
@@ -536,20 +276,12 @@ ClientEngine.prototype = {
             this.service.logout();
             return false;
           case "displayURI":
-            let [uri, clientId, title] = args;
-            URIsToDisplay.push({ uri, clientId, title });
+            this._handleDisplayURI.apply(this, args);
             break;
           default:
             this._log.debug("Received an unknown command: " + command);
             break;
         }
-        // Add the command to the "cleared" commands list
-        this._addClientCommand(this.localID, rawCommand)
-      }
-      this._tracker.addChangedID(this.localID);
-
-      if (URIsToDisplay.length) {
-        this._handleDisplayURIs(URIsToDisplay);
       }
 
       return true;
@@ -588,10 +320,8 @@ ClientEngine.prototype = {
     if (clientId) {
       this._sendCommandToClient(command, args, clientId);
     } else {
-      for (let [id, record] of Object.entries(this._store._remoteClients)) {
-        if (!record.stale) {
-          this._sendCommandToClient(command, args, id);
-        }
+      for (let id in this._store._remoteClients) {
+        this._sendCommandToClient(command, args, id);
       }
     }
   },
@@ -622,11 +352,11 @@ ClientEngine.prototype = {
   },
 
   /**
-   * Handle a bunch of received 'displayURI' commands.
+   * Handle a single received 'displayURI' command.
    *
-   * Interested parties should observe the "weave:engine:clients:display-uris"
-   * topic. The callback will receive an array as the subject parameter
-   * containing objects with the following keys:
+   * Interested parties should observe the "weave:engine:clients:display-uri"
+   * topic. The callback will receive an object as the subject parameter with
+   * the following keys:
    *
    *   uri       URI (string) that is requested for display.
    *   clientId  ID of client that sent the command.
@@ -634,24 +364,21 @@ ClientEngine.prototype = {
    *
    * The 'data' parameter to the callback will not be defined.
    *
-   * @param uris
-   *        An array containing URI objects to display
-   * @param uris[].uri
+   * @param uri
    *        String URI that was received
-   * @param uris[].clientId
+   * @param clientId
    *        ID of client that sent URI
-   * @param uris[].title
+   * @param title
    *        String title of page that URI corresponds to. Older clients may not
    *        send this.
    */
-  _handleDisplayURIs: function _handleDisplayURIs(uris) {
-    Svc.Obs.notify("weave:engine:clients:display-uris", uris);
-  },
+  _handleDisplayURI: function _handleDisplayURI(uri, clientId, title) {
+    this._log.info("Received a URI for display: " + uri + " (" + title +
+                   ") from " + clientId);
 
-  _removeRemoteClient(id) {
-    delete this._store._remoteClients[id];
-    this._tracker.removeChangedID(id);
-  },
+    let subject = {uri: uri, client: clientId, title: title};
+    Svc.Obs.notify("weave:engine:clients:display-uri", subject);
+  }
 };
 
 function ClientStore(name, engine) {
@@ -660,48 +387,29 @@ function ClientStore(name, engine) {
 ClientStore.prototype = {
   __proto__: Store.prototype,
 
-  _remoteClients: {},
-
   create(record) {
-    this.update(record);
+    this.update(record)
   },
 
   update: function update(record) {
-    if (record.id == this.engine.localID) {
-      // Only grab commands from the server; local name/type always wins
+    // Only grab commands from the server; local name/type always wins
+    if (record.id == this.engine.localID)
       this.engine.localCommands = record.commands;
-    } else {
+    else
       this._remoteClients[record.id] = record.cleartext;
-    }
   },
 
   createRecord: function createRecord(id, collection) {
     let record = new ClientsRec(collection, id);
 
-    const commandsChanges = this.engine._currentlySyncingCommands ?
-                            this.engine._currentlySyncingCommands[id] :
-                            [];
-
     // Package the individual components into a record for the local client
     if (id == this.engine.localID) {
-      let cb = Async.makeSpinningCallback();
-      fxAccounts.getDeviceId().then(id => cb(null, id), cb);
-      try {
-        record.fxaDeviceId = cb.wait();
-      } catch(error) {
-        this._log.warn("failed to get fxa device id", error);
-      }
       record.name = this.engine.localName;
       record.type = this.engine.localType;
+      record.commands = this.engine.localCommands;
       record.version = Services.appinfo.version;
       record.protocols = SUPPORTED_PROTOCOL_VERSIONS;
 
-      // Substract the commands we recorded that we've already executed
-      if (commandsChanges && commandsChanges.length &&
-          this.engine.localCommands && this.engine.localCommands.length) {
-        record.commands = this.engine.localCommands.filter(command => !hasDupeCommand(commandsChanges, command));
-      }
-
       // Optional fields.
       record.os = Services.appinfo.OS;             // "Darwin"
       record.appPackage = Services.appinfo.ID;
@@ -712,20 +420,6 @@ ClientStore.prototype = {
       // record.formfactor = "";        // Bug 1100722
     } else {
       record.cleartext = this._remoteClients[id];
-
-      // Add the commands we have to send
-      if (commandsChanges && commandsChanges.length) {
-        const recordCommands = record.cleartext.commands || [];
-        const newCommands = commandsChanges.filter(command => !hasDupeCommand(recordCommands, command));
-        record.cleartext.commands = recordCommands.concat(newCommands);
-      }
-
-      if (record.cleartext.stale) {
-        // It's almost certainly a logic error for us to upload a record we
-        // consider stale, so make log noise, but still remove the flag.
-        this._log.error(`Preparing to upload record ${id} that we consider stale`);
-        delete record.cleartext.stale;
-      }
     }
 
     return record;
@@ -768,7 +462,7 @@ ClientsTracker.prototype = {
         break;
       case "weave:engine:stop-tracking":
         if (this._enabled) {
-          Svc.Prefs.ignore("client.name", this);
+          Svc.Prefs.ignore("clients.name", this);
           this._enabled = false;
         }
         break;
diff --git a/services/sync/modules/engines/forms.js b/services/sync/modules/engines/forms.js
index 43f79d4f7..11dd8d976 100644
--- a/services/sync/modules/engines/forms.js
+++ b/services/sync/modules/engines/forms.js
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-this.EXPORTED_SYMBOLS = ['FormEngine', 'FormRec', 'FormValidator'];
+this.EXPORTED_SYMBOLS = ['FormEngine', 'FormRec'];
 
 var Cc = Components.classes;
 var Ci = Components.interfaces;
@@ -14,10 +14,9 @@ Cu.import("resource://services-sync/record.js");
 Cu.import("resource://services-common/async.js");
 Cu.import("resource://services-sync/util.js");
 Cu.import("resource://services-sync/constants.js");
-Cu.import("resource://services-sync/collection_validator.js");
 Cu.import("resource://gre/modules/Log.jsm");
 
-const FORMS_TTL = 3 * 365 * 24 * 60 * 60;   // Three years in seconds.
+const FORMS_TTL = 5184000; // 60 days
 
 this.FormRec = function FormRec(collection, id) {
   CryptoWrapper.call(this, collection, id);
@@ -37,24 +36,20 @@ var FormWrapper = {
   _getEntryCols: ["fieldname", "value"],
   _guidCols:     ["guid"],
 
-  _promiseSearch: function(terms, searchData) {
-    return new Promise(resolve => {
-      let results = [];
-      let callbacks = {
-        handleResult(result) {
-          results.push(result);
-        },
-        handleCompletion(reason) {
-          resolve(results);
-        }
-      };
-      Svc.FormHistory.search(terms, searchData, callbacks);
-    })
-  },
-
   // Do a "sync" search by spinning the event loop until it completes.
   _searchSpinningly: function(terms, searchData) {
-    return Async.promiseSpinningly(this._promiseSearch(terms, searchData));
+    let results = [];
+    let cb = Async.makeSpinningCallback();
+    let callbacks = {
+      handleResult: function(result) {
+        results.push(result);
+      },
+      handleCompletion: function(reason) {
+        cb(null, results);
+      }
+    };
+    Svc.FormHistory.search(terms, searchData, callbacks);
+    return cb.wait();
   },
 
   _updateSpinningly: function(changes) {
@@ -114,9 +109,7 @@ FormEngine.prototype = {
 
   syncPriority: 6,
 
-  get prefName() {
-    return "history";
-  },
+  get prefName() "history",
 
   _findDupe: function _findDupe(item) {
     return FormWrapper.getGUID(item.name, item.value);
@@ -235,6 +228,7 @@ FormTracker.prototype = {
     if (this.ignoreAll) {
       return;
     }
+
     switch (topic) {
       case "satchel-storage-changed":
         if (data == "formhistory-add" || data == "formhistory-remove") {
@@ -250,56 +244,3 @@ FormTracker.prototype = {
     this.score += SCORE_INCREMENT_MEDIUM;
   },
 };
-
-
-class FormsProblemData extends CollectionProblemData {
-  getSummary() {
-    // We don't support syncing deleted form data, so "clientMissing" isn't a problem
-    return super.getSummary().filter(entry =>
-      entry.name !== "clientMissing");
-  }
-}
-
-class FormValidator extends CollectionValidator {
-  constructor() {
-    super("forms", "id", ["name", "value"]);
-  }
-
-  emptyProblemData() {
-    return new FormsProblemData();
-  }
-
-  getClientItems() {
-    return FormWrapper._promiseSearch(["guid", "fieldname", "value"], {});
-  }
-
-  normalizeClientItem(item) {
-    return {
-      id: item.guid,
-      guid: item.guid,
-      name: item.fieldname,
-      fieldname: item.fieldname,
-      value: item.value,
-      original: item,
-    };
-  }
-
-  normalizeServerItem(item) {
-    let res = Object.assign({
-      guid: item.id,
-      fieldname: item.name,
-      original: item,
-    }, item);
-    // Missing `name` or `value` causes the getGUID call to throw
-    if (item.name !== undefined && item.value !== undefined) {
-      let guid = FormWrapper.getGUID(item.name, item.value);
-      if (guid) {
-        res.guid = guid;
-        res.id = guid;
-        res.duped = true;
-      }
-    }
-
-    return res;
-  }
-}
\ No newline at end of file
diff --git a/services/sync/modules/engines/history.js b/services/sync/modules/engines/history.js
index 307d484c1..e7f53766f 100644
--- a/services/sync/modules/engines/history.js
+++ b/services/sync/modules/engines/history.js
@@ -44,25 +44,6 @@ HistoryEngine.prototype = {
   applyIncomingBatchSize: HISTORY_STORE_BATCH_SIZE,
 
   syncPriority: 7,
-
-  _processIncoming: function (newitems) {
-    // We want to notify history observers that a batch operation is underway
-    // so they don't do lots of work for each incoming record.
-    let observers = PlacesUtils.history.getObservers();
-    function notifyHistoryObservers(notification) {
-      for (let observer of observers) {
-        try {
-          observer[notification]();
-        } catch (ex) { }
-      }
-    }
-    notifyHistoryObservers("onBeginUpdateBatch");
-    try {
-      return SyncEngine.prototype._processIncoming.call(this, newitems);
-    } finally {
-      notifyHistoryObservers("onEndUpdateBatch");
-    }
-  },
 };
 
 function HistoryStore(name, engine) {
@@ -105,7 +86,7 @@ HistoryStore.prototype = {
     return this._getStmt(
       "UPDATE moz_places " +
       "SET guid = :guid " +
-      "WHERE url_hash = hash(:page_url) AND url = :page_url");
+      "WHERE url = :page_url");
   },
 
   // Some helper functions to handle GUIDs
@@ -127,7 +108,7 @@ HistoryStore.prototype = {
     return this._getStmt(
       "SELECT guid " +
       "FROM moz_places " +
-      "WHERE url_hash = hash(:page_url) AND url = :page_url");
+      "WHERE url = :page_url");
   },
   _guidCols: ["guid"],
 
@@ -146,12 +127,12 @@ HistoryStore.prototype = {
   },
 
   get _visitStm() {
-    return this._getStmt(`/* do not warn (bug 599936) */
-      SELECT visit_type type, visit_date date
-      FROM moz_historyvisits
-      JOIN moz_places h ON h.id = place_id
-      WHERE url_hash = hash(:url) AND url = :url
-      ORDER BY date DESC LIMIT 20`);
+    return this._getStmt(
+      "/* do not warn (bug 599936) */ " +
+      "SELECT visit_type type, visit_date date " +
+      "FROM moz_historyvisits " +
+      "WHERE place_id = (SELECT id FROM moz_places WHERE url = :url) " +
+      "ORDER BY date DESC LIMIT 10");
   },
   _visitCols: ["date", "type"],
 
@@ -223,10 +204,7 @@ HistoryStore.prototype = {
         } else {
           shouldApply = this._recordToPlaceInfo(record);
         }
-      } catch (ex) {
-        if (Async.isShutdownException(ex)) {
-          throw ex;
-        }
+      } catch(ex) {
         failed.push(record.id);
         shouldApply = false;
       }
@@ -299,14 +277,14 @@ HistoryStore.prototype = {
       if (!visit.date || typeof visit.date != "number") {
         this._log.warn("Encountered record with invalid visit date: "
                        + visit.date);
-        continue;
+        throw "Visit has no date!";
       }
 
-      if (!visit.type ||
-          !Object.values(PlacesUtils.history.TRANSITIONS).includes(visit.type)) {
-        this._log.warn("Encountered record with invalid visit type: " +
-                       visit.type + "; ignoring.");
-        continue;
+      if (!visit.type || !(visit.type >= PlacesUtils.history.TRANSITION_LINK &&
+                           visit.type <= PlacesUtils.history.TRANSITION_RELOAD)) {
+        this._log.warn("Encountered record with invalid visit type: "
+                       + visit.type);
+        throw "Invalid visit type!";
       }
 
       // Dates need to be integers.
@@ -317,7 +295,6 @@ HistoryStore.prototype = {
         // overwritten.
         continue;
       }
-
       visit.visitDate = visit.date;
       visit.transitionType = visit.type;
       k += 1;
@@ -369,9 +346,7 @@ HistoryStore.prototype = {
   },
 
   wipe: function HistStore_wipe() {
-    let cb = Async.makeSyncCallback();
-    PlacesUtils.history.clear().then(result => {cb(null, result)}, err => {cb(err)});
-    return Async.waitForSyncCallback(cb);
+    PlacesUtils.history.removeAllPages();
   }
 };
 
diff --git a/services/sync/modules/engines/passwords.js b/services/sync/modules/engines/passwords.js
index 51db49a0a..0ccd2e7b0 100644
--- a/services/sync/modules/engines/passwords.js
+++ b/services/sync/modules/engines/passwords.js
@@ -2,16 +2,14 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-this.EXPORTED_SYMBOLS = ['PasswordEngine', 'LoginRec', 'PasswordValidator'];
+this.EXPORTED_SYMBOLS = ['PasswordEngine', 'LoginRec'];
 
 var {classes: Cc, interfaces: Ci, utils: Cu} = Components;
 
 Cu.import("resource://services-sync/record.js");
 Cu.import("resource://services-sync/constants.js");
-Cu.import("resource://services-sync/collection_validator.js");
 Cu.import("resource://services-sync/engines.js");
 Cu.import("resource://services-sync/util.js");
-Cu.import("resource://services-common/async.js");
 
 this.LoginRec = function LoginRec(collection, id) {
   CryptoWrapper.call(this, collection, id);
@@ -24,7 +22,6 @@ LoginRec.prototype = {
 Utils.deferGetSet(LoginRec, "cleartext", [
     "hostname", "formSubmitURL",
     "httpRealm", "username", "password", "usernameField", "passwordField",
-    "timeCreated", "timePasswordChanged",
     ]);
 
 
@@ -70,10 +67,7 @@ PasswordEngine.prototype = {
         Svc.Prefs.set("deletePwdFxA", true);
         Svc.Prefs.reset("deletePwd"); // The old prefname we previously used.
       } catch (ex) {
-        if (Async.isShutdownException(ex)) {
-          throw ex;
-        }
-        this._log.debug("Password deletes failed", ex);
+        this._log.debug("Password deletes failed: ", ex);
       }
     }
   },
@@ -104,13 +98,6 @@ function PasswordStore(name, engine) {
 PasswordStore.prototype = {
   __proto__: Store.prototype,
 
-  _newPropertyBag: function () {
-    return Cc["@mozilla.org/hash-property-bag;1"].createInstance(Ci.nsIWritablePropertyBag2);
-  },
-
-  /**
-   * Return an instance of nsILoginInfo (and, implicitly, nsILoginMetaInfo).
-   */
   _nsLoginInfoFromRecord: function (record) {
     function nullUndefined(x) {
       return (x == undefined) ? null : x;
@@ -131,21 +118,13 @@ PasswordStore.prototype = {
                                      record.password,
                                      record.usernameField,
                                      record.passwordField);
-
     info.QueryInterface(Ci.nsILoginMetaInfo);
     info.guid = record.id;
-    if (record.timeCreated) {
-      info.timeCreated = record.timeCreated;
-    }
-    if (record.timePasswordChanged) {
-      info.timePasswordChanged = record.timePasswordChanged;
-    }
-
     return info;
   },
 
   _getLoginFromGUID: function (id) {
-    let prop = this._newPropertyBag();
+    let prop = Cc["@mozilla.org/hash-property-bag;1"].createInstance(Ci.nsIWritablePropertyBag2);
     prop.setPropertyAsAUTF8String("guid", id);
 
     let logins = Services.logins.searchLogins({}, prop);
@@ -190,7 +169,8 @@ PasswordStore.prototype = {
       return;
     }
 
-    let prop = this._newPropertyBag();
+    let prop = Cc["@mozilla.org/hash-property-bag;1"]
+                 .createInstance(Ci.nsIWritablePropertyBag2);
     prop.setPropertyAsAUTF8String("guid", newID);
 
     Services.logins.modifyLogin(oldLogin, prop);
@@ -217,11 +197,6 @@ PasswordStore.prototype = {
     record.usernameField = login.usernameField;
     record.passwordField = login.passwordField;
 
-    // Optional fields.
-    login.QueryInterface(Ci.nsILoginMetaInfo);
-    record.timeCreated = login.timeCreated;
-    record.timePasswordChanged = login.timePasswordChanged;
-
     return record;
   },
 
@@ -237,7 +212,8 @@ PasswordStore.prototype = {
     try {
       Services.logins.addLogin(login);
     } catch(ex) {
-      this._log.debug(`Adding record ${record.id} resulted in exception`, ex);
+      this._log.debug("Adding record " + record.id +
+                      " resulted in exception ", ex);
     }
   },
 
@@ -269,7 +245,8 @@ PasswordStore.prototype = {
     try {
       Services.logins.modifyLogin(loginItem, newinfo);
     } catch(ex) {
-      this._log.debug(`Modifying record ${record.id} resulted in exception; not modifying`, ex);
+      this._log.debug("Modifying record " + record.id +
+                      " resulted in exception. Not modifying.", ex);
     }
   },
 
@@ -326,46 +303,3 @@ PasswordTracker.prototype = {
     }
   },
 };
-
-class PasswordValidator extends CollectionValidator {
-  constructor() {
-    super("passwords", "id", [
-      "hostname",
-      "formSubmitURL",
-      "httpRealm",
-      "password",
-      "passwordField",
-      "username",
-      "usernameField",
-    ]);
-  }
-
-  getClientItems() {
-    let logins = Services.logins.getAllLogins({});
-    let syncHosts = Utils.getSyncCredentialsHosts()
-    let result = logins.map(l => l.QueryInterface(Ci.nsILoginMetaInfo))
-                       .filter(l => !syncHosts.has(l.hostname));
-    return Promise.resolve(result);
-  }
-
-  normalizeClientItem(item) {
-    return {
-      id: item.guid,
-      guid: item.guid,
-      hostname: item.hostname,
-      formSubmitURL: item.formSubmitURL,
-      httpRealm: item.httpRealm,
-      password: item.password,
-      passwordField: item.passwordField,
-      username: item.username,
-      usernameField: item.usernameField,
-      original: item,
-    }
-  }
-
-  normalizeServerItem(item) {
-    return Object.assign({ guid: item.id }, item);
-  }
-}
-
-
diff --git a/services/sync/modules/engines/prefs.js b/services/sync/modules/engines/prefs.js
index 9ceeb9ac6..792e0c66a 100644
--- a/services/sync/modules/engines/prefs.js
+++ b/services/sync/modules/engines/prefs.js
@@ -8,7 +8,7 @@ var Cc = Components.classes;
 var Ci = Components.interfaces;
 var Cu = Components.utils;
 
-const PREF_SYNC_PREFS_PREFIX = "services.sync.prefs.sync.";
+const SYNC_PREFS_PREFIX = "services.sync.prefs.sync.";
 
 Cu.import("resource://services-sync/engines.js");
 Cu.import("resource://services-sync/record.js");
@@ -42,7 +42,6 @@ PrefsEngine.prototype = {
   version: 2,
 
   syncPriority: 1,
-  allowSkippedRecord: false,
 
   getChangedIDs: function () {
     // No need for a proper timestamp (no conflict resolution needed).
@@ -88,45 +87,37 @@ PrefStore.prototype = {
   _getSyncPrefs: function () {
     let syncPrefs = Cc["@mozilla.org/preferences-service;1"]
                       .getService(Ci.nsIPrefService)
-                      .getBranch(PREF_SYNC_PREFS_PREFIX)
+                      .getBranch(SYNC_PREFS_PREFIX)
                       .getChildList("", {});
     // Also sync preferences that determine which prefs get synced.
-    let controlPrefs = syncPrefs.map(pref => PREF_SYNC_PREFS_PREFIX + pref);
+    let controlPrefs = syncPrefs.map(pref => SYNC_PREFS_PREFIX + pref);
     return controlPrefs.concat(syncPrefs);
   },
 
   _isSynced: function (pref) {
-    return pref.startsWith(PREF_SYNC_PREFS_PREFIX) ||
-           this._prefs.get(PREF_SYNC_PREFS_PREFIX + pref, false);
+    return pref.startsWith(SYNC_PREFS_PREFIX) ||
+            this._prefs.get(SYNC_PREFS_PREFIX + pref, false);
   },
 
   _getAllPrefs: function () {
     let values = {};
-    for (let pref of this._getSyncPrefs()) {
+    for each (let pref in this._getSyncPrefs()) {
       if (this._isSynced(pref)) {
-        // Missing and default prefs get the null value.
-        values[pref] = this._prefs.isSet(pref) ? this._prefs.get(pref, null) : null;
+        // Missing prefs get the null value.
+        values[pref] = this._prefs.get(pref, null);
       }
     }
     return values;
   },
 
-  _updateLightWeightTheme (themeID) {
-    let themeObject = null;
-    if (themeID) {
-      themeObject = LightweightThemeManager.getUsedTheme(themeID);
-    }
-    LightweightThemeManager.currentTheme = themeObject;
-  },
-
   _setAllPrefs: function (values) {
-    let selectedThemeIDPref = "lightweightThemes.selectedThemeID";
-    let selectedThemeIDBefore = this._prefs.get(selectedThemeIDPref, null);
-    let selectedThemeIDAfter = selectedThemeIDBefore;
+    let enabledPref = "lightweightThemes.isThemeSelected";
+    let enabledBefore = this._prefs.get(enabledPref, false);
+    let prevTheme = LightweightThemeManager.currentTheme;
 
     // Update 'services.sync.prefs.sync.foo.pref' before 'foo.pref', otherwise
     // _isSynced returns false when 'foo.pref' doesn't exist (e.g., on a new device).
-    let prefs = Object.keys(values).sort(a => -a.indexOf(PREF_SYNC_PREFS_PREFIX));
+    let prefs = Object.keys(values).sort(a => -a.indexOf(SYNC_PREFS_PREFIX));
     for (let pref of prefs) {
       if (!this._isSynced(pref)) {
         continue;
@@ -134,30 +125,26 @@ PrefStore.prototype = {
 
       let value = values[pref];
 
-      switch (pref) {
-        // Some special prefs we don't want to set directly.
-        case selectedThemeIDPref:
-          selectedThemeIDAfter = value;
-          break;
-
-        // default is to just set the pref
-        default:
-          if (value == null) {
-            // Pref has gone missing. The best we can do is reset it.
-            this._prefs.reset(pref);
-          } else {
-            try {
-              this._prefs.set(pref, value);
-            } catch(ex) {
-              this._log.trace("Failed to set pref: " + pref + ": " + ex);
-            }
-          }
+      // Pref has gone missing. The best we can do is reset it.
+      if (value == null) {
+        this._prefs.reset(pref);
+        continue;
       }
+
+      try {
+        this._prefs.set(pref, value);
+      } catch(ex) {
+        this._log.trace("Failed to set pref: " + pref + ": " + ex);
+      } 
     }
 
-    // Notify the lightweight theme manager if the selected theme has changed.
-    if (selectedThemeIDBefore != selectedThemeIDAfter) {
-      this._updateLightWeightTheme(selectedThemeIDAfter);
+    // Notify the lightweight theme manager of all the new values
+    let enabledNow = this._prefs.get(enabledPref, false);
+    if (enabledBefore && !enabledNow) {
+      LightweightThemeManager.currentTheme = null;
+    } else if (enabledNow && LightweightThemeManager.usedThemes[0] != prevTheme) {
+      LightweightThemeManager.currentTheme = null;
+      LightweightThemeManager.currentTheme = LightweightThemeManager.usedThemes[0];
     }
   },
 
@@ -261,8 +248,8 @@ PrefTracker.prototype = {
       case "nsPref:changed":
         // Trigger a sync for MULTI-DEVICE for a change that determines
         // which prefs are synced or a regular pref change.
-        if (data.indexOf(PREF_SYNC_PREFS_PREFIX) == 0 ||
-            this._prefs.get(PREF_SYNC_PREFS_PREFIX + data, false)) {
+        if (data.indexOf(SYNC_PREFS_PREFIX) == 0 ||
+            this._prefs.get(SYNC_PREFS_PREFIX + data, false)) {
           this.score += SCORE_INCREMENT_XLARGE;
           this.modified = true;
           this._log.trace("Preference " + data + " changed");
diff --git a/services/sync/modules/engines/tabs.js b/services/sync/modules/engines/tabs.js
index 45ece4a23..167faf625 100644
--- a/services/sync/modules/engines/tabs.js
+++ b/services/sync/modules/engines/tabs.js
@@ -43,11 +43,6 @@ TabEngine.prototype = {
   _storeObj: TabStore,
   _trackerObj: TabTracker,
   _recordObj: TabSetRecord,
-  // A flag to indicate if we have synced in this session. This is to help
-  // consumers of remote tabs that may want to differentiate between "I've an
-  // empty tab list as I haven't yet synced" vs "I've an empty tab list
-  // as there really are no tabs"
-  hasSyncedThisSession: false,
 
   syncPriority: 3,
 
@@ -72,7 +67,6 @@ TabEngine.prototype = {
     SyncEngine.prototype._resetClient.call(this);
     this._store.wipe();
     this._tracker.modified = true;
-    this.hasSyncedThisSession = false;
   },
 
   removeClientData: function () {
@@ -100,12 +94,7 @@ TabEngine.prototype = {
     }
 
     return SyncEngine.prototype._reconcile.call(this, item);
-  },
-
-  _syncFinish() {
-    this.hasSyncedThisSession = true;
-    return SyncEngine.prototype._syncFinish.call(this);
-  },
+  }
 };
 
 
@@ -145,7 +134,7 @@ TabStore.prototype = {
       }
 
       for (let tab of win.gBrowser.tabs) {
-        let tabState = this.getTabState(tab);
+        tabState = this.getTabState(tab);
 
         // Make sure there are history entries to look at.
         if (!tabState || !tabState.entries.length) {
@@ -165,11 +154,6 @@ TabStore.prototype = {
           continue;
         }
 
-        if (current.url.length >= (MAX_UPLOAD_BYTES - 1000)) {
-          this._log.trace("Skipping over-long URL.");
-          continue;
-        }
-
         // The element at `index` is the current page. Previous URLs were
         // previously visited URLs; subsequent URLs are in the 'forward' stack,
         // which we can't represent in Sync, so we truncate here.
@@ -189,9 +173,7 @@ TabStore.prototype = {
         allTabs.push({
           title: current.title || "",
           urlHistory: urls,
-          icon: tabState.image ||
-                (tabState.attributes && tabState.attributes.image) ||
-                "",
+          icon: tabState.attributes && tabState.attributes.image || "",
           lastUsed: Math.floor((tabState.lastAccessed || 0) / 1000),
         });
       }
@@ -265,9 +247,27 @@ TabStore.prototype = {
 
   create: function (record) {
     this._log.debug("Adding remote tabs from " + record.clientName);
-    this._remoteClients[record.id] = Object.assign({}, record.cleartext, {
-      lastModified: record.modified
-    });
+    this._remoteClients[record.id] = record.cleartext;
+
+    // Lose some precision, but that's good enough (seconds).
+    let roundModify = Math.floor(record.modified / 1000);
+    let notifyState = Svc.Prefs.get("notifyTabState");
+
+    // If there's no existing pref, save this first modified time.
+    if (notifyState == null) {
+      Svc.Prefs.set("notifyTabState", roundModify);
+      return;
+    }
+
+    // Don't change notifyState if it's already 0 (don't notify).
+    if (notifyState == 0) {
+      return;
+    }
+
+    // We must have gotten a new tab that isn't the same as last time.
+    if (notifyState != roundModify) {
+      Svc.Prefs.set("notifyTabState", 0);
+    }
   },
 
   update: function (record) {
@@ -306,10 +306,6 @@ TabTracker.prototype = {
       window.addEventListener(topic, this.onTab, false);
     }
     window.addEventListener("unload", this._unregisterListeners, false);
-    // If it's got a tab browser we can listen for things like navigation.
-    if (window.gBrowser) {
-      window.gBrowser.addProgressListener(this);
-    }
   },
 
   _unregisterListeners: function (event) {
@@ -322,9 +318,6 @@ TabTracker.prototype = {
     for (let topic of this._topics) {
       window.removeEventListener(topic, this.onTab, false);
     }
-    if (window.gBrowser) {
-      window.gBrowser.removeProgressListener(this);
-    }
   },
 
   startTracking: function () {
@@ -380,14 +373,4 @@ TabTracker.prototype = {
       this.score += SCORE_INCREMENT_SMALL;
     }
   },
-
-  // web progress listeners.
-  onLocationChange: function (webProgress, request, location, flags) {
-    // We only care about top-level location changes which are not in the same
-    // document.
-    if (webProgress.isTopLevel &&
-        ((flags & Ci.nsIWebProgressListener.LOCATION_CHANGE_SAME_DOCUMENT) == 0)) {
-      this.modified = true;
-    }
-  },
 };