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

components/invalidation/p2p_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/p2p_invalidator.h"
 
 #include <algorithm>
 #include <iterator>
 
 #include "base/json/json_reader.h"
@@ skipping 141 matching lines @@
 P2PInvalidator::~P2PInvalidator() {
   DCHECK(thread_checker_.CalledOnValidThread());
   push_client_->RemoveObserver(this);
 }
 
 void P2PInvalidator::RegisterHandler(InvalidationHandler* handler) {
   DCHECK(thread_checker_.CalledOnValidThread());
   registrar_.RegisterHandler(handler);
 }
 
-void P2PInvalidator::UpdateRegisteredIds(InvalidationHandler* handler,
+bool P2PInvalidator::UpdateRegisteredIds(InvalidationHandler* handler,
                                          const ObjectIdSet& ids) {
   DCHECK(thread_checker_.CalledOnValidThread());
   ObjectIdSet new_ids;
   const ObjectIdSet& old_ids = registrar_.GetRegisteredIds(handler);
   std::set_difference(ids.begin(), ids.end(),
                       old_ids.begin(), old_ids.end(),
                       std::inserter(new_ids, new_ids.end()),
                       ObjectIdLessThan());
-  registrar_.UpdateRegisteredIds(handler, ids);
+  if (!registrar_.UpdateRegisteredIds(handler, ids))
+    return false;
   const P2PNotificationData notification_data(
       invalidator_client_id_,
       send_notification_target_,
       ObjectIdInvalidationMap::InvalidateAll(ids));
   SendNotificationData(notification_data);
+  return true;
 }
 
 void P2PInvalidator::UnregisterHandler(InvalidationHandler* handler) {
   DCHECK(thread_checker_.CalledOnValidThread());
   registrar_.UnregisterHandler(handler);
 }
 
 InvalidatorState P2PInvalidator::GetInvalidatorState() const {
   DCHECK(thread_checker_.CalledOnValidThread());
   return registrar_.GetInvalidatorState();
@@ skipping 104 matching lines @@
     return;
   }
   notifier::Notification notification;
   notification.channel = kSyncP2PNotificationChannel;
   notification.data = notification_data.ToString();
   DVLOG(1) << "Sending XMPP notification: " << notification.ToString();
   push_client_->SendNotification(notification);
 }
 
 }  // namespace syncer