[Sync] Avoid unregistering object IDs on shutdown

sync/notifier/non_blocking_invalidation_notifier.h

Index: sync/notifier/non_blocking_invalidation_notifier.h
diff --git a/sync/notifier/non_blocking_invalidation_notifier.h b/sync/notifier/non_blocking_invalidation_notifier.h
index f76b37b9e2736cfa79c89cd2a1d949044ad949af..0e7ebad022892b5e9fa476210383b12cf72ba514 100644
--- a/sync/notifier/non_blocking_invalidation_notifier.h
+++ b/sync/notifier/non_blocking_invalidation_notifier.h
@@ -27,6 +27,7 @@ class SingleThreadTaskRunner;
 
 namespace syncer {
 
+// Generalize to NonBlockingSyncNotifier (http://crbug.com/140409).
 class NonBlockingInvalidationNotifier
     : public SyncNotifier,
       // SyncNotifierObserver to "observe" our Core via WeakHandle.
@@ -44,7 +45,9 @@ class NonBlockingInvalidationNotifier
   virtual ~NonBlockingInvalidationNotifier();
 
   // SyncNotifier implementation.
-  virtual void UpdateRegisteredIds(SyncNotifierObserver* handler,
+  virtual void SetHandler(const std::string& handler_name,
+                          SyncNotifierObserver* handler) OVERRIDE;
+  virtual void UpdateRegisteredIds(const std::string& handler_name,
                                    const ObjectIdSet& ids) OVERRIDE;
   virtual void SetUniqueId(const std::string& unique_id) OVERRIDE;
   virtual void SetStateDeprecated(const std::string& state) OVERRIDE;