drive: Add the local largest changestamp to chrome:drive-internals

chrome/browser/chromeos/drive/mock_drive_file_system.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_DRIVE_MOCK_DRIVE_FILE_SYSTEM_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_MOCK_DRIVE_FILE_SYSTEM_H_
 
 #include <string>
 
 #include "chrome/browser/chromeos/drive/drive_file_system_interface.h"
@@ skipping 82 matching lines @@
                                scoped_ptr<gdata::DocumentEntry> entry,
                                const FilePath& file_content_path,
                                DriveCache::FileOperationType cache_operation,
                                const base::Closure& callback) OVERRIDE {}
   // This function is not mockable by gmock because scoped_ptr is not supported.
   virtual void UpdateEntryData(const std::string& resource_id,
                                const std::string& md5,
                                scoped_ptr<gdata::DocumentEntry> entry,
                                const FilePath& file_content_path,
                                const base::Closure& callback) OVERRIDE {}
+  MOCK_CONST_METHOD0(GetMetadata, DriveFileSystemMetadata());
 };
 
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_MOCK_DRIVE_FILE_SYSTEM_H_