[Sync] Initial USS service implementation for DeviceInfo.

components/sync_driver/device_info_sync_service.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_DRIVER_DEVICE_INFO_SYNC_SERVICE_H_
 #define COMPONENTS_SYNC_DRIVER_DEVICE_INFO_SYNC_SERVICE_H_
 
 #include <map>
 #include <string>
 
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
 #include "base/observer_list.h"
 #include "components/sync_driver/device_info_tracker.h"
 #include "sync/api/sync_change_processor.h"
 #include "sync/api/sync_data.h"
 #include "sync/api/sync_error_factory.h"
 #include "sync/api/syncable_service.h"
 
 namespace sync_driver {
 
 class LocalDeviceInfoProvider;
@@ skipping 32 matching lines @@
   base::Time GetLocalDeviceBackupTime() const;
 
  private:
   // Create SyncData from local DeviceInfo and |local_device_backup_time_|.
   syncer::SyncData CreateLocalData(const DeviceInfo* info);
   // Create SyncData from EntitySpecifics.
   static syncer::SyncData CreateLocalData(
       const sync_pb::EntitySpecifics& entity);
 
   // Allocate new DeviceInfo from SyncData.
-  static DeviceInfo* CreateDeviceInfo(const syncer::SyncData sync_data);
+  static DeviceInfo* CreateDeviceInfo(const syncer::SyncData& sync_data);
   // Store SyncData in the cache.
   void StoreSyncData(const std::string& client_id,
                      const syncer::SyncData& sync_data);
   // Delete SyncData from the cache.
   void DeleteSyncData(const std::string& client_id);
   // Notify all registered observers.
   void NotifyObservers();
 
   // Updates backup time in place in |sync_data| if it is different than
   // the one stored in |local_device_backup_time_|.
@@ skipping 28 matching lines @@
 
   // Registered observers, not owned.
   base::ObserverList<Observer, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceInfoSyncService);
 };
 
 }  // namespace sync_driver
 
 #endif  // COMPONENTS_SYNC_DRIVER_DEVICE_INFO_SYNC_SERVICE_H_