[Sync] InvalidationService shouldn't CHECK when registering ObjectId for more than one handler

components/invalidation/p2p_invalidation_service.h

Index: components/invalidation/p2p_invalidation_service.h
diff --git a/components/invalidation/p2p_invalidation_service.h b/components/invalidation/p2p_invalidation_service.h
index 741f1658b9d5f4c39338c212cbeb6628c37a692d..c0096e4557ebf0b4f43df04b194d047385fc7f43 100644
--- a/components/invalidation/p2p_invalidation_service.h
+++ b/components/invalidation/p2p_invalidation_service.h
@@ -40,7 +40,7 @@ class P2PInvalidationService : public base::NonThreadSafe,
   // It is an error to have registered handlers when the service is destroyed.
   void RegisterInvalidationHandler(
       syncer::InvalidationHandler* handler) override;
-  void UpdateRegisteredInvalidationIds(syncer::InvalidationHandler* handler,
+  bool UpdateRegisteredInvalidationIds(syncer::InvalidationHandler* handler,
                                        const syncer::ObjectIdSet& ids) override;
   void UnregisterInvalidationHandler(
       syncer::InvalidationHandler* handler) override;