Implement TouchFile on drive::FileSystem.

chrome/browser/chromeos/drive/file_system.cc

 // 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.
 
 #include "chrome/browser/chromeos/drive/file_system.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/metrics/histogram.h"
@@ skipping 401 matching lines @@
 
 void FileSystem::TouchFile(const base::FilePath& file_path,
                            const base::Time& last_access_time,
                            const base::Time& last_modified_time,
                            const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!last_access_time.is_null());
   DCHECK(!last_modified_time.is_null());
   DCHECK(!callback.is_null());
 
-  // TODO(hidehiko): Implement this (crbug.com/144369).
-  NOTIMPLEMENTED();
+  drive_operations_.TouchFile(
+      file_path, last_access_time, last_modified_time, callback);
 }
 
 void FileSystem::Pin(const base::FilePath& file_path,
                      const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!callback.is_null());
 
   GetResourceEntryByPath(file_path,
                          base::Bind(&FileSystem::PinAfterGetResourceEntryByPath,
                                     weak_ptr_factory_.GetWeakPtr(),
@@ skipping 1228 matching lines @@
   util::ConvertPlatformFileInfoToResourceEntry(*file_info, &entry_file_info);
   *entry->mutable_file_info() = entry_file_info;
   callback.Run(FILE_ERROR_OK, entry.Pass());
 }
 
 void FileSystem::CancelJobInScheduler(JobID id) {
   scheduler_->CancelJob(id);
 }
 
 }  // namespace drive