Update sync client for JS changes.

28 files changed, 155 insertions, 130 deletions

diff --git a/services/sync/modules/addonsreconciler.js b/services/sync/modules/addonsreconciler.js
index 2e838e885..96752a511 100644
--- a/services/sync/modules/addonsreconciler.js
+++ b/services/sync/modules/addonsreconciler.js
@@ -17,7 +17,7 @@
 
 "use strict";
 
-const Cu = Components.utils;
+var Cu = Components.utils;
 
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-sync/util.js");
@@ -218,11 +218,12 @@ AddonsReconciler.prototype = {
       }
 
       this._addons = json.addons;
-      for each (let record in this._addons) {
+      for (let id in this._addons) {
+        let record = this._addons[id];
         record.modified = new Date(record.modified);
       }
 
-      for each (let [time, change, id] in json.changes) {
+      for (let [time, change, id] of json.changes) {
         this._changes.push([new Date(time), change, id]);
       }
 
@@ -246,9 +247,9 @@ AddonsReconciler.prototype = {
     let file = path || DEFAULT_STATE_FILE;
     let state = {version: 1, addons: {}, changes: []};
 
-    for (let [id, record] in Iterator(this._addons)) {
+    for (let [id, record] of Object.entries(this._addons)) {
       state.addons[id] = {};
-      for (let [k, v] in Iterator(record)) {
+      for (let [k, v] of Object.entries(record)) {
         if (k == "modified") {
           state.addons[id][k] = v.getTime();
         }
@@ -258,7 +259,7 @@ AddonsReconciler.prototype = {
       }
     }
 
-    for each (let [time, change, id] in this._changes) {
+    for (let [time, change, id] of this._changes) {
       state.changes.push([time.getTime(), change, id]);
     }
 
@@ -350,14 +351,14 @@ AddonsReconciler.prototype = {
     AddonManager.getAllAddons(function (addons) {
       let ids = {};
 
-      for each (let addon in addons) {
+      for (let addon of addons) {
         ids[addon.id] = true;
         this.rectifyStateFromAddon(addon);
       }
 
       // Look for locally-defined add-ons that no longer exist and update their
       // record.
-      for (let [id, addon] in Iterator(this._addons)) {
+      for (let [id, addon] of Object.entries(this._addons)) {
         if (id in ids) {
           continue;
         }
@@ -373,7 +374,7 @@ AddonsReconciler.prototype = {
         }
 
         let installFound = false;
-        for each (let install in installs) {
+        for (let install of installs) {
           if (install.addon && install.addon.id == id &&
               install.state == AddonManager.STATE_INSTALLED) {
 
@@ -416,7 +417,7 @@ AddonsReconciler.prototype = {
    *        Addon instance being updated.
    */
   rectifyStateFromAddon: function rectifyStateFromAddon(addon) {
-    this._log.debug("Rectifying state for addon: " + addon.id);
+    this._log.debug(`Rectifying state for addon ${addon.name} (version=${addon.version}, id=${addon.id})`);
     this._ensureStateLoaded();
 
     let id = addon.id;
@@ -483,7 +484,7 @@ AddonsReconciler.prototype = {
     this._log.info("Change recorded for " + state.id);
     this._changes.push([date, change, state.id]);
 
-    for each (let listener in this._listeners) {
+    for (let listener of this._listeners) {
       try {
         listener.changeListener.call(listener, date, change, state);
       } catch (ex) {
@@ -554,7 +555,8 @@ AddonsReconciler.prototype = {
    * @return Object on success on null on failure.
    */
   getAddonStateFromSyncGUID: function getAddonStateFromSyncGUID(guid) {
-    for each (let addon in this.addons) {
+    for (let id in this.addons) {
+      let addon = this.addons[id];
       if (addon.guid == guid) {
         return addon;
       }
diff --git a/services/sync/modules/addonutils.js b/services/sync/modules/addonutils.js
index 54b441b9e..11b6b0397 100644
--- a/services/sync/modules/addonutils.js
+++ b/services/sync/modules/addonutils.js
@@ -6,7 +6,7 @@
 
 this.EXPORTED_SYMBOLS = ["AddonUtils"];
 
-const {interfaces: Ci, utils: Cu} = Components;
+var {interfaces: Ci, utils: Cu} = Components;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Log.jsm");
@@ -248,7 +248,7 @@ AddonUtilsInternal.prototype = {
     }
 
     let ids = [];
-    for each (let addon in installs) {
+    for (let addon of installs) {
       ids.push(addon.id);
     }
 
@@ -298,7 +298,7 @@ AddonUtilsInternal.prototype = {
         // server-side metrics aren't skewed (bug 708134). The server should
         // ideally send proper URLs, but this solution was deemed too
         // complicated at the time the functionality was implemented.
-        for each (let addon in addons) {
+        for (let addon of addons) {
           // sourceURI presence isn't enforced by AddonRepository. So, we skip
           // add-ons without a sourceURI.
           if (!addon.sourceURI) {
@@ -342,9 +342,9 @@ AddonUtilsInternal.prototype = {
 
         // Start all the installs asynchronously. They will report back to us
         // as they finish, eventually triggering the global callback.
-        for each (let addon in toInstall) {
+        for (let addon of toInstall) {
           let options = {};
-          for each (let install in installs) {
+          for (let install of installs) {
             if (install.id == addon.id) {
               options = install;
               break;
@@ -365,7 +365,7 @@ AddonUtilsInternal.prototype = {
   /**
    * Update the user disabled flag for an add-on.
    *
-   * The supplied callback will ba called when the operation is
+   * The supplied callback will be called when the operation is
    * complete. If the new flag matches the existing or if the add-on
    * isn't currently active, the function will fire the callback
    * immediately. Else, the callback is invoked when the AddonManager
diff --git a/services/sync/modules/browserid_identity.js b/services/sync/modules/browserid_identity.js
index bc8ea6b30..9709b9196 100644
--- a/services/sync/modules/browserid_identity.js
+++ b/services/sync/modules/browserid_identity.js
@@ -6,7 +6,7 @@
 
 this.EXPORTED_SYMBOLS = ["BrowserIDManager"];
 
-const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
+var {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-common/async.js");
@@ -39,7 +39,7 @@ XPCOMUtils.defineLazyGetter(this, 'log', function() {
 });
 
 // FxAccountsCommon.js doesn't use a "namespace", so create one here.
-let fxAccountsCommon = {};
+var fxAccountsCommon = {};
 Cu.import("resource://gre/modules/FxAccountsCommon.js", fxAccountsCommon);
 
 const OBSERVER_TOPICS = [
@@ -144,7 +144,7 @@ this.BrowserIDManager.prototype = {
     // re-entering of credentials by the user is necessary we don't take any
     // further action - an observer will fire when the user does that.
     if (Weave.Status.login == LOGIN_FAILED_LOGIN_REJECTED) {
-      return Promise.reject();
+      return Promise.reject(new Error("User needs to re-authenticate"));
     }
 
     // So - we've a previous auth problem and aren't currently attempting to
diff --git a/services/sync/modules/engines.js b/services/sync/modules/engines.js
index eabddae2b..35e8d6954 100644
--- a/services/sync/modules/engines.js
+++ b/services/sync/modules/engines.js
@@ -10,7 +10,7 @@ this.EXPORTED_SYMBOLS = [
   "Store"
 ];
 
-const {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
+var {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
 
 Cu.import("resource://services-common/async.js");
 Cu.import("resource://gre/modules/Log.jsm");
@@ -104,7 +104,7 @@ Tracker.prototype = {
     Utils.jsonLoad("changes/" + this.file, this, function(json) {
       if (json && (typeof(json) == "object")) {
         this.changedIDs = json;
-      } else {
+      } else if (json !== null) {
         this._log.warn("Changed IDs file " + this.file + " contains non-object value.");
         json = null;
       }
@@ -135,7 +135,7 @@ Tracker.prototype = {
       return false;
     }
 
-    if (this.ignoreAll || (id in this._ignored)) {
+    if (this.ignoreAll || this._ignored.includes(id)) {
       return false;
     }
 
@@ -159,8 +159,9 @@ Tracker.prototype = {
       this._log.warn("Attempted to remove undefined ID to tracker");
       return false;
     }
-    if (this.ignoreAll || (id in this._ignored))
+    if (this.ignoreAll || this._ignored.includes(id)) {
       return false;
+    }
     if (this.changedIDs[id] != null) {
       this._log.trace("Removing changed ID " + id);
       delete this.changedIDs[id];
@@ -299,7 +300,7 @@ Store.prototype = {
    */
   applyIncomingBatch: function (records) {
     let failed = [];
-    for each (let record in records) {
+    for (let record of records) {
       try {
         this.applyIncoming(record);
       } catch (ex if (ex.code == Engine.prototype.eEngineAbortApplyIncoming)) {
@@ -483,7 +484,11 @@ EngineManager.prototype = {
   },
 
   getAll: function () {
-    return [engine for ([name, engine] in Iterator(this._engines))];
+    let engines = [];
+    for (let [, engine] of Object.entries(this._engines)) {
+      engines.push(engine);
+    }
+    return engines;
   },
 
   /**
@@ -496,7 +501,7 @@ EngineManager.prototype = {
   },
 
   get enabledEngineNames() {
-    return [e.name for each (e in this.getEnabled())];
+    return this.getEnabled().map(e => e.name);
   },
 
   persistDeclined: function () {
@@ -1245,7 +1250,7 @@ SyncEngine.prototype = {
     // because some state may change during the course of this function and we
     // need to operate on the original values.
     let existsLocally   = this._store.itemExists(item.id);
-    let locallyModified = item.id in this._modified;
+    let locallyModified = this._modified.has(item.id);
 
     // TODO Handle clock drift better. Tracked in bug 721181.
     let remoteAge = AsyncResource.serverTime - item.modified;
@@ -1444,14 +1449,14 @@ SyncEngine.prototype = {
                           + failed_ids.join(", "));
 
         // Clear successfully uploaded objects.
-        for each (let id in resp.obj.success) {
+        for (let id of resp.obj.success) {
           delete this._modified[id];
         }
 
         up.clearRecords();
       });
 
-      for each (let id in modifiedIDs) {
+      for (let id of modifiedIDs) {
         try {
           let out = this._createRecord(id);
           if (this._log.level <= Log.Level.Trace)
@@ -1489,7 +1494,7 @@ SyncEngine.prototype = {
       coll.delete();
     });
 
-    for (let [key, val] in Iterator(this._delete)) {
+    for (let [key, val] of Object.entries(this._delete)) {
       // Remove the key for future uses
       delete this._delete[key];
 
diff --git a/services/sync/modules/engines/addons.js b/services/sync/modules/engines/addons.js
index ab3131c30..3081e3e87 100644
--- a/services/sync/modules/engines/addons.js
+++ b/services/sync/modules/engines/addons.js
@@ -33,7 +33,7 @@
  */
 "use strict";
 
-const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
+var {classes: Cc, interfaces: Ci, utils: Cu} = Components;
 
 Cu.import("resource://services-sync/addonutils.js");
 Cu.import("resource://services-sync/addonsreconciler.js");
@@ -150,7 +150,7 @@ AddonsEngine.prototype = {
    */
   getChangedIDs: function getChangedIDs() {
     let changes = {};
-    for (let [id, modified] in Iterator(this._tracker.changedIDs)) {
+    for (let [id, modified] of Object.entries(this._tracker.changedIDs)) {
       changes[id] = modified;
     }
 
@@ -160,7 +160,7 @@ AddonsEngine.prototype = {
     // we assume this function is only called from within a sync.
     let reconcilerChanges = this._reconciler.getChangesSinceDate(lastSyncDate);
     let addons = this._reconciler.addons;
-    for each (let change in reconcilerChanges) {
+    for (let change of reconcilerChanges) {
       let changeTime = change[0];
       let id = change[2];
 
@@ -291,7 +291,7 @@ AddonsStore.prototype = {
       id:               record.addonID,
       syncGUID:         record.id,
       enabled:          record.enabled,
-      requireSecureURI: !Svc.Prefs.get("addons.ignoreRepositoryChecking", false),
+      requireSecureURI: this._extensionsPrefs.get("install.requireSecureOrigin", true),
     }], cb);
 
     // This will throw if there was an error. This will get caught by the sync
@@ -299,7 +299,7 @@ AddonsStore.prototype = {
     let results = cb.wait();
 
     let addon;
-    for each (let a in results.addons) {
+    for (let a of results.addons) {
       if (a.id == record.addonID) {
         addon = a;
         break;
@@ -443,7 +443,8 @@ AddonsStore.prototype = {
     let ids = {};
 
     let addons = this.reconciler.addons;
-    for each (let addon in addons) {
+    for (let id in addons) {
+      let addon = addons[id];
       if (this.isAddonSyncable(addon)) {
         ids[addon.guid] = true;
       }
diff --git a/services/sync/modules/engines/bookmarks.js b/services/sync/modules/engines/bookmarks.js
index 1936afc3f..42d91f57e 100644
--- a/services/sync/modules/engines/bookmarks.js
+++ b/services/sync/modules/engines/bookmarks.js
@@ -6,9 +6,9 @@ this.EXPORTED_SYMBOLS = ['BookmarksEngine', "PlacesItem", "Bookmark",
                          "BookmarkFolder", "BookmarkQuery",
                          "Livemark", "BookmarkSeparator"];
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cu = Components.utils;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cu = Components.utils;
 
 Cu.import("resource://gre/modules/PlacesUtils.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
diff --git a/services/sync/modules/engines/clients.js b/services/sync/modules/engines/clients.js
index f423242c9..6c8e37a7b 100644
--- a/services/sync/modules/engines/clients.js
+++ b/services/sync/modules/engines/clients.js
@@ -7,7 +7,7 @@ this.EXPORTED_SYMBOLS = [
   "ClientsRec"
 ];
 
-const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
+var {classes: Cc, interfaces: Ci, utils: Cu} = Components;
 
 Cu.import("resource://services-common/stringbundle.js");
 Cu.import("resource://services-sync/constants.js");
@@ -66,10 +66,13 @@ ClientEngine.prototype = {
       numClients: 1,
     };
 
-    for each (let {name, type} in this._store._remoteClients) {
-      stats.hasMobile = stats.hasMobile || type == "mobile";
-      stats.names.push(name);
-      stats.numClients++;
+    for (let id in this._store._remoteClients) {
+      let {name, type, stale} = this._store._remoteClients[id];
+      if (!stale) {
+        stats.hasMobile = stats.hasMobile || type == DEVICE_TYPE_MOBILE;
+        stats.names.push(name);
+        stats.numClients++;
+      }
     }
 
     return stats;
@@ -85,7 +88,11 @@ ClientEngine.prototype = {
 
     counts.set(this.localType, 1);
 
-    for each (let record in this._store._remoteClients) {
+    for (let id in this._store._remoteClients) {
+      let record = this._store._remoteClients[id];
+      if (record.stale) {
+        continue; // pretend "stale" records don't exist.
+      }
       let type = record.type;
       if (!counts.has(type)) {
         counts.set(type, 0);
diff --git a/services/sync/modules/engines/forms.js b/services/sync/modules/engines/forms.js
index d26d57176..26b289119 100644
--- a/services/sync/modules/engines/forms.js
+++ b/services/sync/modules/engines/forms.js
@@ -4,9 +4,9 @@
 
 this.EXPORTED_SYMBOLS = ['FormEngine', 'FormRec'];
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cu = Components.utils;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cu = Components.utils;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://services-sync/engines.js");
@@ -30,7 +30,7 @@ FormRec.prototype = {
 Utils.deferGetSet(FormRec, "cleartext", ["name", "value"]);
 
 
-let FormWrapper = {
+var FormWrapper = {
   _log: Log.repository.getLogger("Sync.Engine.Forms"),
 
   _getEntryCols: ["fieldname", "value"],
diff --git a/services/sync/modules/engines/history.js b/services/sync/modules/engines/history.js
index 99ecb4506..7c8aabf83 100644
--- a/services/sync/modules/engines/history.js
+++ b/services/sync/modules/engines/history.js
@@ -4,10 +4,10 @@
 
 this.EXPORTED_SYMBOLS = ['HistoryEngine', 'HistoryRec'];
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cu = Components.utils;
-const Cr = Components.results;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cu = Components.utils;
+var Cr = Components.results;
 
 const HISTORY_TTL = 5184000; // 60 days
 
@@ -51,7 +51,8 @@ function HistoryStore(name, engine) {
 
   // Explicitly nullify our references to our cached services so we don't leak
   Svc.Obs.add("places-shutdown", function() {
-    for each ([query, stmt] in Iterator(this._stmts)) {
+    for (let query in this._stmts) {
+      let stmt = this._stmts;
       stmt.finalize();
     }
     this._stmts = {};
diff --git a/services/sync/modules/engines/passwords.js b/services/sync/modules/engines/passwords.js
index 994b59767..2837b6a10 100644
--- a/services/sync/modules/engines/passwords.js
+++ b/services/sync/modules/engines/passwords.js
@@ -4,7 +4,7 @@
 
 this.EXPORTED_SYMBOLS = ['PasswordEngine', 'LoginRec'];
 
-const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
+var {classes: Cc, interfaces: Ci, utils: Cu} = Components;
 
 Cu.import("resource://services-sync/record.js");
 Cu.import("resource://services-sync/constants.js");
@@ -83,7 +83,7 @@ PasswordEngine.prototype = {
     this._store._sleep(0); // Yield back to main thread after synchronous operation.
 
     // Look for existing logins that match the hostname, but ignore the password.
-    for each (let local in logins) {
+    for (let local of logins) {
       if (login.matches(local, true) && local instanceof Ci.nsILoginMetaInfo) {
         return local.guid;
       }
diff --git a/services/sync/modules/engines/prefs.js b/services/sync/modules/engines/prefs.js
index 82091d5b4..792e0c66a 100644
--- a/services/sync/modules/engines/prefs.js
+++ b/services/sync/modules/engines/prefs.js
@@ -4,9 +4,9 @@
 
 this.EXPORTED_SYMBOLS = ['PrefsEngine', 'PrefRec'];
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cu = Components.utils;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cu = Components.utils;
 
 const SYNC_PREFS_PREFIX = "services.sync.prefs.sync.";
 
diff --git a/services/sync/modules/engines/tabs.js b/services/sync/modules/engines/tabs.js
index 1fce737d2..167faf625 100644
--- a/services/sync/modules/engines/tabs.js
+++ b/services/sync/modules/engines/tabs.js
@@ -4,7 +4,7 @@
 
 this.EXPORTED_SYMBOLS = ["TabEngine", "TabSetRecord"];
 
-const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
+var {classes: Cc, interfaces: Ci, utils: Cu} = Components;
 
 const TABS_TTL = 604800;           // 7 days.
 const TAB_ENTRIES_LIMIT = 25;      // How many URLs to include in tab history.
@@ -302,7 +302,7 @@ TabTracker.prototype = {
 
   _registerListenersForWindow: function (window) {
     this._log.trace("Registering tab listeners in window");
-    for each (let topic in this._topics) {
+    for (let topic of this._topics) {
       window.addEventListener(topic, this.onTab, false);
     }
     window.addEventListener("unload", this._unregisterListeners, false);
@@ -315,7 +315,7 @@ TabTracker.prototype = {
   _unregisterListenersForWindow: function (window) {
     this._log.trace("Removing tab listeners in window");
     window.removeEventListener("unload", this._unregisterListeners, false);
-    for each (let topic in this._topics) {
+    for (let topic of this._topics) {
       window.removeEventListener(topic, this.onTab, false);
     }
   },
diff --git a/services/sync/modules/identity.js b/services/sync/modules/identity.js
index 2bee13b5b..cd28f5efe 100644
--- a/services/sync/modules/identity.js
+++ b/services/sync/modules/identity.js
@@ -6,7 +6,7 @@
 
 this.EXPORTED_SYMBOLS = ["IdentityManager"];
 
-const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
+var {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Promise.jsm");
@@ -206,7 +206,7 @@ IdentityManager.prototype = {
         return null;
       }
 
-      for each (let login in this._getLogins(PWDMGR_PASSWORD_REALM)) {
+      for (let login of this._getLogins(PWDMGR_PASSWORD_REALM)) {
         if (login.username.toLowerCase() == username) {
           // It should already be UTF-8 encoded, but we don't take any chances.
           this._basicPassword = Utils.encodeUTF8(login.password);
@@ -260,7 +260,7 @@ IdentityManager.prototype = {
         return null;
       }
 
-      for each (let login in this._getLogins(PWDMGR_PASSPHRASE_REALM)) {
+      for (let login of this._getLogins(PWDMGR_PASSPHRASE_REALM)) {
         if (login.username.toLowerCase() == username) {
           this._syncKey = login.password;
         }
@@ -411,7 +411,7 @@ IdentityManager.prototype = {
         this._setLogin(PWDMGR_PASSWORD_REALM, this.username,
                        this._basicPassword);
       } else {
-        for each (let login in this._getLogins(PWDMGR_PASSWORD_REALM)) {
+        for (let login of this._getLogins(PWDMGR_PASSWORD_REALM)) {
           Services.logins.removeLogin(login);
         }
       }
@@ -423,7 +423,7 @@ IdentityManager.prototype = {
       if (this._syncKey) {
         this._setLogin(PWDMGR_PASSPHRASE_REALM, this.username, this._syncKey);
       } else {
-        for each (let login in this._getLogins(PWDMGR_PASSPHRASE_REALM)) {
+        for (let login of this._getLogins(PWDMGR_PASSPHRASE_REALM)) {
           Services.logins.removeLogin(login);
         }
       }
@@ -477,7 +477,7 @@ IdentityManager.prototype = {
    */
   _setLogin: function _setLogin(realm, username, password) {
     let exists = false;
-    for each (let login in this._getLogins(realm)) {
+    for (let login of this._getLogins(realm)) {
       if (login.username == username && login.password == password) {
         exists = true;
       } else {
@@ -513,7 +513,7 @@ IdentityManager.prototype = {
   deleteSyncCredentials: function deleteSyncCredentials() {
     for (let host of this._getSyncCredentialsHosts()) {
       let logins = Services.logins.findLogins({}, host, "", "");
-      for each (let login in logins) {
+      for (let login of logins) {
         Services.logins.removeLogin(login);
       }
     }
diff --git a/services/sync/modules/jpakeclient.js b/services/sync/modules/jpakeclient.js
index 10f405371..625dc91b6 100644
--- a/services/sync/modules/jpakeclient.js
+++ b/services/sync/modules/jpakeclient.js
@@ -4,7 +4,7 @@
 
 this.EXPORTED_SYMBOLS = ["JPAKEClient", "SendCredentialsController"];
 
-const {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
+var {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
 
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-common/rest.js");
@@ -281,8 +281,7 @@ JPAKEClient.prototype = {
     let rng = Cc["@mozilla.org/security/random-generator;1"]
                 .createInstance(Ci.nsIRandomGenerator);
     let bytes = rng.generateRandomBytes(JPAKE_LENGTH_CLIENTID / 2);
-    this._clientID = [("0" + byte.toString(16)).slice(-2)
-                      for each (byte in bytes)].join("");
+    this._clientID = bytes.map(byte => ("0" + byte.toString(16)).slice(-2)).join("");
   },
 
   _createSecret: function _createSecret() {
@@ -291,8 +290,7 @@ JPAKEClient.prototype = {
     let rng = Cc["@mozilla.org/security/random-generator;1"]
                 .createInstance(Ci.nsIRandomGenerator);
     let bytes = rng.generateRandomBytes(JPAKE_LENGTH_SECRET);
-    return [key[Math.floor(byte * key.length / 256)]
-            for each (byte in bytes)].join("");
+    return bytes.map(byte => key[Math.floor(byte * key.length / 256)]).join("");
   },
 
   _newRequest: function _newRequest(uri) {
diff --git a/services/sync/modules/keys.js b/services/sync/modules/keys.js
index bf909bdc2..b93de7f31 100644
--- a/services/sync/modules/keys.js
+++ b/services/sync/modules/keys.js
@@ -9,7 +9,7 @@ this.EXPORTED_SYMBOLS = [
   "SyncKeyBundle"
 ];
 
-const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
+var {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 
 Cu.import("resource://services-sync/constants.js");
 Cu.import("resource://gre/modules/Log.jsm");
diff --git a/services/sync/modules/main.js b/services/sync/modules/main.js
index 488a2594b..e8e705e72 100644
--- a/services/sync/modules/main.js
+++ b/services/sync/modules/main.js
@@ -6,7 +6,7 @@ this.EXPORTED_SYMBOLS = ['Weave'];
 
 this.Weave = {};
 Components.utils.import("resource://services-sync/constants.js", Weave);
-let lazies = {
+var lazies = {
   "jpakeclient.js":       ["JPAKEClient", "SendCredentialsController"],
   "notifications.js":     ["Notifications", "Notification", "NotificationButton"],
   "service.js":           ["Service"],
@@ -15,12 +15,14 @@ let lazies = {
 };
 
 function lazyImport(module, dest, props) {
-  function getter(prop) function() {
-    let ns = {};
-    Components.utils.import(module, ns);
-    delete dest[prop];
-    return dest[prop] = ns[prop];
-  };
+  function getter(prop) {
+    return function() {
+      let ns = {};
+      Components.utils.import(module, ns);
+      delete dest[prop];
+      return dest[prop] = ns[prop];
+    };
+  }
   props.forEach(function (prop) { dest.__defineGetter__(prop, getter(prop)); });
 }
 
diff --git a/services/sync/modules/notifications.js b/services/sync/modules/notifications.js
index 1ee24f2cd..72187a4ce 100644
--- a/services/sync/modules/notifications.js
+++ b/services/sync/modules/notifications.js
@@ -4,10 +4,10 @@
 
 this.EXPORTED_SYMBOLS = ["Notifications", "Notification", "NotificationButton"];
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cr = Components.results;
-const Cu = Components.utils;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cr = Components.results;
+var Cu = Components.utils;
 
 Cu.import("resource://services-common/observers.js");
 Cu.import("resource://gre/modules/Log.jsm");
diff --git a/services/sync/modules/policies.js b/services/sync/modules/policies.js
index d799cb235..38f118d3f 100644
--- a/services/sync/modules/policies.js
+++ b/services/sync/modules/policies.js
@@ -7,7 +7,7 @@ this.EXPORTED_SYMBOLS = [
   "SyncScheduler",
 ];
 
-const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
+var {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-sync/constants.js");
diff --git a/services/sync/modules/record.js b/services/sync/modules/record.js
index 04ccd2dd2..e609ad1bc 100644
--- a/services/sync/modules/record.js
+++ b/services/sync/modules/record.js
@@ -10,10 +10,10 @@ this.EXPORTED_SYMBOLS = [
   "Collection",
 ];
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cr = Components.results;
-const Cu = Components.utils;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cr = Components.results;
+var Cu = Components.utils;
 
 const CRYPTO_COLLECTION = "crypto";
 const KEYS_WBO = "keys";
@@ -85,7 +85,7 @@ WBORecord.prototype = {
   toJSON: function toJSON() {
     // Copy fields from data to be stringified, making sure payload is a string
     let obj = {};
-    for (let [key, val] in Iterator(this.data))
+    for (let [key, val] of Object.entries(this.data))
       obj[key] = key == "payload" ? JSON.stringify(val) : val;
     if (this.ttl)
       obj.ttl = this.ttl;
@@ -309,7 +309,7 @@ CollectionKeyManager.prototype = {
     // Return a sorted, unique array.
     changed.sort();
     let last;
-    changed = [x for each (x in changed) if ((x != last) && (last = x))];
+    changed = changed.filter(x => (x != last) && (last = x));
     return {same: changed.length == 0,
             changed: changed};
   },
diff --git a/services/sync/modules/resource.js b/services/sync/modules/resource.js
index 1c2a67b90..b31d129a5 100644
--- a/services/sync/modules/resource.js
+++ b/services/sync/modules/resource.js
@@ -7,10 +7,10 @@ this.EXPORTED_SYMBOLS = [
   "Resource"
 ];
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cr = Components.results;
-const Cu = Components.utils;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cr = Components.results;
+var Cu = Components.utils;
 
 Cu.import("resource://gre/modules/Preferences.jsm");
 Cu.import("resource://services-common/async.js");
@@ -174,7 +174,7 @@ AsyncResource.prototype = {
     if (this.authenticator) {
       let result = this.authenticator(this, method);
       if (result && result.headers) {
-        for (let [k, v] in Iterator(result.headers)) {
+        for (let [k, v] of Object.entries(result.headers)) {
           headers[k.toLowerCase()] = v;
         }
       }
@@ -182,7 +182,7 @@ AsyncResource.prototype = {
       this._log.debug("No authenticator found.");
     }
 
-    for (let [key, value] in Iterator(headers)) {
+    for (let [key, value] of Object.entries(headers)) {
       if (key == 'authorization')
         this._log.trace("HTTP Header " + key + ": ***** (suppressed)");
       else
diff --git a/services/sync/modules/rest.js b/services/sync/modules/rest.js
index 34382eed5..106ece222 100644
--- a/services/sync/modules/rest.js
+++ b/services/sync/modules/rest.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/. */
 
-const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
+var {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-common/rest.js");
diff --git a/services/sync/modules/service.js b/services/sync/modules/service.js
index 637760b8f..f3837a949 100644
--- a/services/sync/modules/service.js
+++ b/services/sync/modules/service.js
@@ -4,10 +4,10 @@
 
 this.EXPORTED_SYMBOLS = ["Service"];
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cr = Components.results;
-const Cu = Components.utils;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cr = Components.results;
+var Cu = Components.utils;
 
 // How long before refreshing the cluster
 const CLUSTER_BACKOFF = 5 * 60 * 1000; // 5 minutes
@@ -432,7 +432,7 @@ Sync11Service.prototype = {
 
     // Map each old pref to the current pref branch
     let oldPref = new Preferences(oldPrefBranch);
-    for each (let pref in oldPrefNames)
+    for (let pref of oldPrefNames)
       Svc.Prefs.set(pref, oldPref.get(pref));
 
     // Remove all the old prefs and remember that we've migrated
@@ -890,7 +890,7 @@ Sync11Service.prototype = {
     // Deletion doesn't make sense if we aren't set up yet!
     if (this.clusterURL != "") {
       // Clear client-specific data from the server, including disabled engines.
-      for each (let engine in [this.clientsEngine].concat(this.engineManager.getAll())) {
+      for (let engine of [this.clientsEngine].concat(this.engineManager.getAll())) {
         try {
           engine.removeClientData();
         } catch(ex) {
@@ -1497,7 +1497,7 @@ Sync11Service.prototype = {
 
     // Wipe everything we know about except meta because we just uploaded it
     let engines = [this.clientsEngine].concat(this.engineManager.getAll());
-    let collections = [engine.name for each (engine in engines)];
+    let collections = engines.map(engine => engine.name);
     // TODO: there's a bug here. We should be calling resetClient, no?
 
     // Generate, upload, and download new keys. Do this last so we don't wipe
@@ -1657,7 +1657,7 @@ Sync11Service.prototype = {
       }
 
       // Have each engine drop any temporary meta data
-      for each (let engine in engines) {
+      for (let engine of engines) {
         engine.resetClient();
       }
     })();
diff --git a/services/sync/modules/stages/cluster.js b/services/sync/modules/stages/cluster.js
index dd358bf98..41afe61d8 100644
--- a/services/sync/modules/stages/cluster.js
+++ b/services/sync/modules/stages/cluster.js
@@ -4,7 +4,7 @@
 
 this.EXPORTED_SYMBOLS = ["ClusterManager"];
 
-const {utils: Cu} = Components;
+var {utils: Cu} = Components;
 
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-sync/constants.js");
diff --git a/services/sync/modules/stages/declined.js b/services/sync/modules/stages/declined.js
index b0877e929..ff8a14181 100644
--- a/services/sync/modules/stages/declined.js
+++ b/services/sync/modules/stages/declined.js
@@ -11,7 +11,7 @@
 
 this.EXPORTED_SYMBOLS = ["DeclinedEngines"];
 
-const {utils: Cu} = Components;
+var {utils: Cu} = Components;
 
 Cu.import("resource://services-sync/constants.js");
 Cu.import("resource://gre/modules/Log.jsm");
@@ -29,8 +29,8 @@ this.DeclinedEngines = function (service) {
 }
 this.DeclinedEngines.prototype = {
   updateDeclined: function (meta, engineManager=this.service.engineManager) {
-    let enabled = new Set([e.name for each (e in engineManager.getEnabled())]);
-    let known = new Set([e.name for each (e in engineManager.getAll())]);
+    let enabled = new Set(engineManager.getEnabled().map(e => e.name));
+    let known = new Set(engineManager.getAll().map(e => e.name));
     let remoteDeclined = new Set(meta.payload.declined || []);
     let localDeclined = new Set(engineManager.getDeclined());
 
diff --git a/services/sync/modules/stages/enginesync.js b/services/sync/modules/stages/enginesync.js
index ed91adddb..ce7fce94d 100644
--- a/services/sync/modules/stages/enginesync.js
+++ b/services/sync/modules/stages/enginesync.js
@@ -8,7 +8,7 @@
 
 this.EXPORTED_SYMBOLS = ["EngineSynchronizer"];
 
-const {utils: Cu} = Components;
+var {utils: Cu} = Components;
 
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-sync/constants.js");
@@ -224,8 +224,15 @@ EngineSynchronizer.prototype = {
     // If we're the only client, and no engines are marked as enabled,
     // thumb our noses at the server data: it can't be right.
     // Belt-and-suspenders approach to Bug 615926.
-    if ((numClients <= 1) &&
-        ([e for (e in meta.payload.engines) if (e != "clients")].length == 0)) {
+    let hasEnabledEngines = false;
+    for (let e in meta.payload.engines) {
+      if (e != "clients") {
+        hasEnabledEngines = true;
+        break;
+      }
+    }
+
+    if ((numClients <= 1) && !hasEnabledEngines) {
       this._log.info("One client and no enabled engines: not touching local engine status.");
       return;
     }
@@ -289,7 +296,7 @@ EngineSynchronizer.prototype = {
     }
 
     // Any remaining engines were either enabled locally or disabled remotely.
-    for each (let engineName in enabled) {
+    for (let engineName of enabled) {
       let engine = engineManager.get(engineName);
       if (Svc.Prefs.get("engineStatusChanged." + engine.prefName, false)) {
         this._log.trace("The " + engineName + " engine was enabled locally.");
diff --git a/services/sync/modules/status.js b/services/sync/modules/status.js
index 19dff9712..4b26f62bd 100644
--- a/services/sync/modules/status.js
+++ b/services/sync/modules/status.js
@@ -4,10 +4,10 @@
 
 this.EXPORTED_SYMBOLS = ["Status"];
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cr = Components.results;
-const Cu = Components.utils;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cr = Components.results;
+var Cu = Components.utils;
 
 Cu.import("resource://services-sync/constants.js");
 Cu.import("resource://gre/modules/Log.jsm");
diff --git a/services/sync/modules/userapi.js b/services/sync/modules/userapi.js
index ec77d63e2..e906440bd 100644
--- a/services/sync/modules/userapi.js
+++ b/services/sync/modules/userapi.js
@@ -8,7 +8,7 @@ this.EXPORTED_SYMBOLS = [
   "UserAPI10Client",
 ];
 
-const {utils: Cu} = Components;
+var {utils: Cu} = Components;
 
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-common/rest.js");
diff --git a/services/sync/modules/util.js b/services/sync/modules/util.js
index 67cc3f063..b063a29ac 100644
--- a/services/sync/modules/util.js
+++ b/services/sync/modules/util.js
@@ -4,7 +4,7 @@
 
 this.EXPORTED_SYMBOLS = ["XPCOMUtils", "Services", "Utils", "Async", "Svc", "Str"];
 
-const {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
+var {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
 
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-common/observers.js");
@@ -338,12 +338,14 @@ this.Utils = {
 
     try {
       json = yield CommonUtils.readJSON(path);
-    } catch (e if e instanceof OS.File.Error && e.becauseNoSuchFile) {
-      // Ignore non-existent files.
     } catch (e) {
-      if (that._log) {
-        that._log.debug("Failed to load json: " +
-                        CommonUtils.exceptionStr(e));
+      if (e instanceof OS.File.Error && e.becauseNoSuchFile) {
+        // Ignore non-existent files, but explicitly return null.
+        json = null;
+      } else {
+        if (that._log) {
+          that._log.debug("Failed to load json", e);
+        }
       }
     }
 
@@ -690,7 +692,7 @@ Svc.Prefs = new Preferences(PREFS_BRANCH);
 Svc.DefaultPrefs = new Preferences({branch: PREFS_BRANCH, defaultBranch: true});
 Svc.Obs = Observers;
 
-let _sessionCID = Services.appinfo.ID == SEAMONKEY_ID ?
+var _sessionCID = Services.appinfo.ID == SEAMONKEY_ID ?
   "@mozilla.org/suite/sessionstore;1" :
   "@mozilla.org/browser/sessionstore;1";