[NOCOMMIT] Make DriveService{Wrapper|Messenger} class

chrome/browser/sync_file_system/drive_backend/sync_engine_context.h

 // Copyright 2013 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 CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_CONTEXT_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_CONTEXT_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 12 matching lines @@
 
 class RemoteChangeProcessor;
 
 namespace drive_backend {
 
 class MetadataDatabase;
 
 class SyncEngineContext {
  public:
   SyncEngineContext(
-      drive::DriveServiceInterface* drive_service,
+      scoped_ptr<drive::DriveServiceInterface> drive_service,
       drive::DriveUploaderInterface* drive_uploader,
       base::SequencedTaskRunner* ui_task_runner,
       base::SequencedTaskRunner* file_task_runner);
   ~SyncEngineContext();
 
   drive::DriveServiceInterface* GetDriveService();
   drive::DriveUploaderInterface* GetDriveUploader();
   MetadataDatabase* GetMetadataDatabase();
   RemoteChangeProcessor* GetRemoteChangeProcessor();
   base::SequencedTaskRunner* GetUiTaskRunner();
   base::SequencedTaskRunner* GetFileTaskRunner();
 
   void SetMetadataDatabase(scoped_ptr<MetadataDatabase> metadata_database);
   void SetRemoteChangeProcessor(RemoteChangeProcessor* remote_change_processor);
 
   scoped_ptr<MetadataDatabase> PassMetadataDatabase();
 
  private:
-  drive::DriveServiceInterface* drive_service_;
+  scoped_ptr<drive::DriveServiceInterface> drive_service_;
+
   drive::DriveUploaderInterface* drive_uploader_;
   RemoteChangeProcessor* remote_change_processor_;
 
   scoped_ptr<MetadataDatabase> metadata_database_;
   scoped_refptr<base::SequencedTaskRunner> ui_task_runner_;
   scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncEngineContext);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_CONTEXT_H_