[Sync] Avoid unregistering object IDs on shutdown

chrome/browser/sync/glue/bridged_sync_notifier.h

Index: chrome/browser/sync/glue/bridged_sync_notifier.h
diff --git a/chrome/browser/sync/glue/bridged_sync_notifier.h b/chrome/browser/sync/glue/bridged_sync_notifier.h
index f48d0f9daaafe7d032517d055c9bab092f11eccd..616e16da9d984c8232b83cb88efec792296b0847 100644
--- a/chrome/browser/sync/glue/bridged_sync_notifier.h
+++ b/chrome/browser/sync/glue/bridged_sync_notifier.h
@@ -28,9 +28,13 @@ class BridgedSyncNotifier : public syncer::SyncNotifier {
   virtual ~BridgedSyncNotifier();
 
   // SyncNotifier implementation. Passes through all calls to the delegate.
-  // UpdateRegisteredIds calls will also be forwarded to the bridge.
+  // RegisterHandler, UnregisterHandler, and UpdateRegisteredIds calls will
+  // also be forwarded to the bridge.
+  virtual void RegisterHandler(syncer::SyncNotifierObserver* handler) OVERRIDE;
   virtual void UpdateRegisteredIds(syncer::SyncNotifierObserver* handler,
                                    const syncer::ObjectIdSet& ids) OVERRIDE;
+  virtual void UnregisterHandler(
+      syncer::SyncNotifierObserver* handler) OVERRIDE;
   virtual void SetUniqueId(const std::string& unique_id) OVERRIDE;
   virtual void SetStateDeprecated(const std::string& state) OVERRIDE;
   virtual void UpdateCredentials(