Add UpdateOperationTest for drive::file_system::UpdateOperationTest.

chrome/browser/google_apis/fake_drive_service.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/google_apis/fake_drive_service.h"
 
 #include <string>
 
 #include "base/logging.h"
 #include "base/message_loop.h"
@@ skipping 995 matching lines @@
     MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    UploadRangeResponse(HTTP_RESUME_INCOMPLETE,
                                        start_position,
                                        end_position),
                     base::Passed(&result_entry)));
     return;
   }
 
+  AddNewChangestamp(entry);
   result_entry = ResourceEntry::CreateFrom(*entry).Pass();
 
   std::string upload_mode;
   bool upload_mode_found =
       net::GetValueForKeyInQuery(upload_url, "mode", &upload_mode);
   DCHECK(upload_mode_found &&
          (upload_mode == "newfile" || upload_mode == "existing"));
 
   GDataErrorCode return_code =
       upload_mode == "newfile" ? HTTP_CREATED : HTTP_SUCCESS;
@@ skipping 403 matching lines @@
   if (load_counter)
     *load_counter += 1;
   MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback,
                  HTTP_SUCCESS,
                  base::Passed(&resource_list)));
 }
 
 }  // namespace google_apis