Use Drive v2 API: enable behind --enable-drive-api flag

chrome/browser/chromeos/gdata/gdata_system_service.h

 // Copyright (c) 2012 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_CHROMEOS_GDATA_GDATA_SYSTEM_SERVICE_H_
 #define CHROME_BROWSER_CHROMEOS_GDATA_GDATA_SYSTEM_SERVICE_H_
 #pragma once
 
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/chromeos/gdata/gdata_file_system.h"
@@ skipping 53 matching lines @@
   Profile* profile_;
   const base::SequencedWorkerPool::SequenceToken sequence_token_;
   GDataCache* cache_;
   scoped_ptr<DocumentsServiceInterface> documents_service_;
   scoped_ptr<GDataUploader> uploader_;
   scoped_ptr<DriveWebAppsRegistry> webapps_registry_;
   scoped_ptr<GDataFileSystem> file_system_;
   scoped_ptr<GDataDownloadObserver> download_observer_;
   scoped_ptr<GDataSyncClient> sync_client_;
 
+  // If true use Drive v2 API instead of Document List API.
+  bool use_drive_api_;
+
   DISALLOW_COPY_AND_ASSIGN(GDataSystemService);
 };
 
 // Singleton that owns all GDataSystemServices and associates them with
 // Profiles.
 class GDataSystemServiceFactory : public ProfileKeyedServiceFactory {
  public:
   // Returns the GDataSystemService for |profile|, creating it if it is not
   // yet created.
   static GDataSystemService* GetForProfile(Profile* profile);
@@ skipping 11 matching lines @@
   virtual ~GDataSystemServiceFactory();
 
   // ProfileKeyedServiceFactory:
   virtual ProfileKeyedService* BuildServiceInstanceFor(
       Profile* profile) const OVERRIDE;
 };
 
 }  // namespace gdata
 
 #endif  // CHROME_BROWSER_CHROMEOS_GDATA_GDATA_SYSTEM_SERVICE_H_