[Background Sync] Use GcmNetworkManager to start the browser for sync events.

content/browser/background_sync/background_sync_manager.h

 // Copyright 2015 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.
 
 #ifndef CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_MANAGER_H_
 #define CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_MANAGER_H_
 
 #include <map>
 #include <string>
 #include <utility>
@@ skipping 256 matching lines @@
 
   bool AreOptionConditionsMet(const BackgroundSyncRegistrationOptions& options);
   bool IsRegistrationReadyToFire(
       const BackgroundSyncRegistration& registration);
 
   // Schedules pending registrations to run in the future. For one-shots this
   // means keeping the browser alive so that network connectivity events can be
   // seen (on Android the browser is instead woken up the next time it goes
   // online). For periodic syncs this means creating an alarm.
   void SchedulePendingRegistrations();
+  void SchedulePendingRegistrationsOnUIThread(
+      bool keep_browser_alive_for_one_shot);
 
   // FireReadyEvents and callbacks
   void FireReadyEvents();
   void FireReadyEventsImpl(const base::Closure& callback);
   void FireReadyEventsDidFindRegistration(
       const RegistrationKey& registration_key,
       BackgroundSyncRegistration::RegistrationId registration_id,
       const base::Closure& event_fired_callback,
       const base::Closure& event_completed_callback,
       ServiceWorkerStatusCode service_worker_status,
@@ skipping 66 matching lines @@
         BackgroundSyncRegistrationHandle::HandleId> registration_handle_ids_;
 
   base::WeakPtrFactory<BackgroundSyncManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundSyncManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_MANAGER_H_