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

components/invalidation/fake_invalidator.h

Index: components/invalidation/fake_invalidator.h
diff --git a/components/invalidation/fake_invalidator.h b/components/invalidation/fake_invalidator.h
index b040027f69c129f25e59997fb82ebab7150f9a35..2d24361b2716794595c18226e403e28914ada33e 100644
--- a/components/invalidation/fake_invalidator.h
+++ b/components/invalidation/fake_invalidator.h
@@ -31,7 +31,7 @@ class FakeInvalidator : public Invalidator {
       const ObjectIdInvalidationMap& invalidation_map);
 
   void RegisterHandler(InvalidationHandler* handler) override;
-  void UpdateRegisteredIds(InvalidationHandler* handler,
+  bool UpdateRegisteredIds(InvalidationHandler* handler,
                            const ObjectIdSet& ids) override;
   void UnregisterHandler(InvalidationHandler* handler) override;
   InvalidatorState GetInvalidatorState() const override;