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

chrome/common/json_pref_store.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/json_pref_store.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/file_util.h"
-#include "base/json/json_value_serializer.h"
+#include "base/json/json_file_value_serializer.h"
+#include "base/json/json_string_value_serializer.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop_proxy.h"
 #include "base/values.h"
 
 namespace {
 
 // Some extensions we'll tack on to copies of the Preferences files.
 const FilePath::CharType* kBadExtension = FILE_PATH_LITERAL("bad");
 
 // Differentiates file loading between origin thread and passed
@@ skipping 275 matching lines @@
 }
 
 bool JsonPrefStore::SerializeData(std::string* output) {
   // TODO(tc): Do we want to prune webkit preferences that match the default
   // value?
   JSONStringValueSerializer serializer(output);
   serializer.set_pretty_print(true);
   scoped_ptr<DictionaryValue> copy(prefs_->DeepCopyWithoutEmptyChildren());
   return serializer.Serialize(*(copy.get()));
 }