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

components/invalidation/fake_invalidator.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/invalidation/fake_invalidator.h"
 
 #include "components/invalidation/object_id_invalidation_map.h"
 
 namespace syncer {
 
@@ skipping 24 matching lines @@
 
 void FakeInvalidator::EmitOnIncomingInvalidation(
     const ObjectIdInvalidationMap& invalidation_map) {
   registrar_.DispatchInvalidationsToHandlers(invalidation_map);
 }
 
 void FakeInvalidator::RegisterHandler(InvalidationHandler* handler) {
   registrar_.RegisterHandler(handler);
 }
 
-void FakeInvalidator::UpdateRegisteredIds(InvalidationHandler* handler,
+bool FakeInvalidator::UpdateRegisteredIds(InvalidationHandler* handler,
                                           const ObjectIdSet& ids) {
-  registrar_.UpdateRegisteredIds(handler, ids);
+  return registrar_.UpdateRegisteredIds(handler, ids);
 }
 
 void FakeInvalidator::UnregisterHandler(InvalidationHandler* handler) {
   registrar_.UnregisterHandler(handler);
 }
 
 InvalidatorState FakeInvalidator::GetInvalidatorState() const {
   return registrar_.GetInvalidatorState();
 }
 
 void FakeInvalidator::UpdateCredentials(
     const std::string& email, const std::string& token) {
   email_ = email;
   token_ = token;
 }
 
 void FakeInvalidator::RequestDetailedStatus(
     base::Callback<void(const base::DictionaryValue&)> callback) const {
   base::DictionaryValue value;
   callback.Run(value);
 }
 }  // namespace syncer