--- a/services/sync/modules/engines/tabs.js
+++ b/services/sync/modules/engines/tabs.js
@@ -32,30 +32,29 @@
  * and other provisions required by the GPL or the LGPL. If you do not delete
  * the provisions above, a recipient may use your version of this file under
  * the terms of any one of the MPL, the GPL or the LGPL.
  *
  * ***** END LICENSE BLOCK ***** */
 
 const EXPORTED_SYMBOLS = ['TabEngine'];
 
-const SESSION_STORE_KEY = "weave-tab-sync-id";
-
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://weave/util.js");
 Cu.import("resource://weave/async.js");
 Cu.import("resource://weave/engines.js");
 Cu.import("resource://weave/stores.js");
 Cu.import("resource://weave/trackers.js");
 Cu.import("resource://weave/constants.js");
 Cu.import("resource://weave/type_records/tabs.js");
+Cu.import("resource://weave/engines/clientData.js");
 
 Function.prototype.async = Async.sugar;
 
 function TabEngine() {
   this._init();
 }
 TabEngine.prototype = {
   __proto__: SyncEngine.prototype,
@@ -89,21 +88,21 @@ TabStore.prototype = {
 
   _TabStore_init: function TabStore__init() {
     dump("Initializing TabStore!!\n");
     this._init();
     this._readFromFile();
   },
 
   get _localClientGUID() {
-    return Engines.get("clients").clientID;
+    return Clients.clientID;
   },
 
   get _localClientName() {
-    return Engines.get("clients").clientName;
+    return Clients.clientName;
   },
 
   _writeToFile: function TabStore_writeToFile() {
     // use JSON service to serialize the records...
     this._log.debug("Writing out to file...");
     let file = Utils.getProfileFile(
       {path: this._filePath, autoCreate: true});
     let jsonObj = {};
@@ -134,16 +133,17 @@ TabStore.prototype = {
 	this._remoteClients[id].id = id;
       }
     } catch (e) {
       this._log.warn("Failed to load saved tabs file" + e);
     }
   },
 
   get _sessionStore() {
+    // TODO: sessionStore seems to not exist on Fennec?
     let sessionStore = Cc["@mozilla.org/browser/sessionstore;1"].
 		       getService(Ci.nsISessionStore);
     this.__defineGetter__("_sessionStore", function() { return sessionStore;});
     return this._sessionStore;
   },
 
   get _json() {
     let json = Cc["@mozilla.org/dom/json;1"].createInstance(Ci.nsIJSON);
@@ -212,17 +212,17 @@ TabStore.prototype = {
     if (this._remoteClients[oldId]) {
       let record = this._remoteClients[oldId];
       record.id = newId;
       delete this._remoteClients[oldId];
       this._remoteClients[newId] = record;
     }
   },
 
-  getAllIds: function TabStore_getAllIds() {
+  getAllIDs: function TabStore_getAllIds() {
     this._log.debug("getAllIds called.");
     let items = {};
     items[ this._localClientGUID ] = true;
     for (let id in this._remoteClients) {
       items[id] = true;
     }
     return items;
   },
@@ -286,17 +286,22 @@ TabTracker.prototype = {
     ww.registerNotification(this);
   },
 
   observe: function TabTracker_observe(aSubject, aTopic, aData) {
     dump("TabTracker spotted window open/close...\n");
     let window = aSubject.QueryInterface(Ci.nsIDOMWindow);
     // TODO: Not all windows have tabContainers.  Fennec windows don't,
     // for instance.
-    let container = window.getBrowser().tabContainer;
+    if (! window.getBrowser)
+      return;
+    let browser = window.getBrowser();
+    if (! browser.tabContainer)
+      return;
+    let container = browser.tabContainer;
     if (aTopic == "domwindowopened") {
       container.addEventListener("TabOpen", this.onTabChanged, false);
       container.addEventListener("TabClose", this.onTabChanged, false);
     } else if (aTopic == "domwindowclosed") {
       container.removeEventListener("TabOpen", this.onTabChanged, false);
       container.removeEventListener("TabClose", this.onTabChanged, false);
     }
   },