Wire FileSystemOperation::TouchFile to Drive.

webkit/chromeos/fileapi/remote_file_system_proxy.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 WEBKIT_CHROMEOS_FILEAPI_REMOTE_FILE_SYSTEM_PROXY_H_
 #define WEBKIT_CHROMEOS_FILEAPI_REMOTE_FILE_SYSTEM_PROXY_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "webkit/fileapi/file_system_operation.h"
@@ skipping 85 matching lines @@
   // base::PlatformFileFlags for details).
   virtual void OpenFile(
       const FileSystemURL& url,
       int flags,
       base::ProcessHandle peer_handle,
       const FileSystemOperation::OpenFileCallback& callback) = 0;
 
   // Notifies that a file opened by OpenFile (at |path|) is closed.
   virtual void NotifyCloseFile(const FileSystemURL& url) = 0;
 
-  // TODO(zelidrag): More methods to follow as we implement other parts of FSO.
+  // Modifies the timestamp of a given |url| to |last_access_time| and
+  // |last_modified_time|. Note that unlike 'touch' command of Linux, it
+  // does not create a new file.
+  virtual void TouchFile(
+      const fileapi::FileSystemURL& url,
+      const base::Time& last_access_time,
+      const base::Time& last_modified_time,
+      const FileSystemOperation::StatusCallback& callback) = 0;
 
  protected:
   friend class base::RefCountedThreadSafe<RemoteFileSystemProxyInterface>;
   virtual ~RemoteFileSystemProxyInterface() {}
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_CHROMEOS_FILEAPI_REMOTE_FILE_SYSTEM_PROXY_H_