[NOCOMMIT] Make DriveService{Wrapper|Messenger} class

chrome/browser/sync_file_system/drive_backend/drive_service_wrapper.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 "chrome/browser/sync_file_system/drive_backend/drive_service_wrapper.h"
+
+namespace sync_file_system {
+namespace drive_backend {
+
+DriveServiceWrapper::DriveServiceWrapper(
+    drive::DriveServiceInterface* drive_service)
+    : drive_service_(drive_service) {
+  DCHECK(drive_service_);
+}
+
+DriveServiceWrapper::~DriveServiceWrapper() {}
+
+drive::DriveServiceInterface* DriveServiceWrapper::GetDriveService() {
+  return drive_service_;
+}
+
+}  // namespace drive_backend
+}  // namespace sync_file_system