Merge 68891 - [Sync] Fixed sync crash regression in ServerNotifierThread

chrome/browser/sync/notifier/server_notifier_thread.cc

 // Copyright (c) 2010 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 "chrome/browser/sync/notifier/server_notifier_thread.h"
 
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 105 matching lines @@
     // generated from our own changes.
     const std::string kClientId = "server_notifier_thread";
     chrome_invalidation_client_->Start(
         kClientId, state_, this, this, base_task_);
     state_.clear();
   }
 }
 
 void ServerNotifierThread::RegisterTypesAndSignalSubscribed() {
   DCHECK_EQ(MessageLoop::current(), worker_message_loop());
-  DCHECK(chrome_invalidation_client_.get());
+  if (!chrome_invalidation_client_.get()) {
+    return;
+  }
   chrome_invalidation_client_->RegisterTypes();
   observers_->Notify(&Observer::OnSubscriptionStateChange, true);
 }
 
 void ServerNotifierThread::StopInvalidationListener() {
   DCHECK_EQ(MessageLoop::current(), worker_message_loop());
   chrome_invalidation_client_.reset();
 }
 
 }  // namespace sync_notifier