[Sync] Avoid unregistering object IDs on shutdown

chrome/browser/sync/glue/chrome_sync_notification_bridge.h

Index: chrome/browser/sync/glue/chrome_sync_notification_bridge.h
diff --git a/chrome/browser/sync/glue/chrome_sync_notification_bridge.h b/chrome/browser/sync/glue/chrome_sync_notification_bridge.h
index a878ff711f14e999c7282a637f1108433ef7d8b0..64ea85c71ba7ee3a391a94da953f2150faa2b648 100644
--- a/chrome/browser/sync/glue/chrome_sync_notification_bridge.h
+++ b/chrome/browser/sync/glue/chrome_sync_notification_bridge.h
@@ -36,10 +36,17 @@ class ChromeSyncNotificationBridge : public content::NotificationObserver {
       const scoped_refptr<base::SequencedTaskRunner>& sync_task_runner);
   virtual ~ChromeSyncNotificationBridge();
 
+  // Must be called on the UI thread while the sync task runner is
+  // still around.  No other member functions on the sync thread may
+  // be called after this is called.
+  void StopForShutdown();
+
   // Must be called on the sync task runner.
   void UpdateEnabledTypes(syncer::ModelTypeSet enabled_types);
   // Marked virtual for tests.
-  virtual void UpdateRegisteredIds(syncer::SyncNotifierObserver* handler,
+  virtual void SetHandler(const std::string& handler_name,
+                          syncer::SyncNotifierObserver* handler);
+  virtual void UpdateRegisteredIds(const std::string& handler_name,
                                    const syncer::ObjectIdSet& ids);
 
   // NotificationObserver implementation. Called on UI thread.