--- a/browser/metro/base/content/bindings/browser.js
+++ b/browser/metro/base/content/bindings/browser.js
@@ -4,16 +4,19 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 let Cc = Components.classes;
 let Ci = Components.interfaces;
 let Cu = Components.utils;
 
 Cu.import("resource://gre/modules/Services.jsm");
 
+XPCOMUtils.defineLazyServiceGetter(this, "gUUIDGenerator",
+                                   "@mozilla.org/uuid-generator;1", "nsIUUIDGenerator");
+
 let WebProgressListener = {
   _lastLocation: null,
   _firstPaint: false,
 
   init: function() {
     let flags = Ci.nsIWebProgress.NOTIFY_LOCATION |
                 Ci.nsIWebProgress.NOTIFY_SECURITY |
                 Ci.nsIWebProgress.NOTIFY_STATE_WINDOW |
@@ -255,17 +258,17 @@ let WebNavigation =  {
       shEntry.cacheKey = cacheKey;
     }
 
     if (aEntry.ID) {
       // get a new unique ID for this frame (since the one from the last
       // start might already be in use)
       let id = aIdMap[aEntry.ID] || 0;
       if (!id) {
-        for (id = Date.now(); id in aIdMap.used; id++);
+        id = gUUIDGenerator.generateUUID();
         aIdMap[aEntry.ID] = id;
         aIdMap.used[id] = true;
       }
       shEntry.ID = id;
     }
 
     if (aEntry.docshellID)
       shEntry.docshellID = aEntry.docshellID;