Break two classes defined in json_value_serializer.cc, .h into separate files.

chrome/common/extensions/extension_file_util.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/common/extensions/extension_file_util.h"
 
 #include <map>
 #include <vector>
 
 #include "base/file_util.h"
-#include "base/json/json_value_serializer.h"
+#include "base/json/json_file_value_serializer.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
 #include "base/scoped_temp_dir.h"
 #include "base/stringprintf.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_action.h"
@@ skipping 665 matching lines @@
     return temp_path;
 
   return FilePath();
 }
 
 void DeleteFile(const FilePath& path, bool recursive) {
   file_util::Delete(path, recursive);
 }
 
 }  // namespace extension_file_util