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

chrome/browser/chromeos/cros/onc_network_parser.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/cros/onc_network_parser.h"
 
 #include <keyhi.h>
 #include <pk11pub.h>
 
 #include "base/base64.h"
-#include "base/json/json_value_serializer.h"
+#include "base/json/json_string_value_serializer.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "base/json/json_writer.h"  // for debug output only.
 #include "base/stringprintf.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/cros/certificate_pattern.h"
 #include "chrome/browser/chromeos/cros/native_network_constants.h"
 #include "chrome/browser/chromeos/cros/native_network_parser.h"
 #include "chrome/browser/chromeos/cros/network_library.h"
 #include "chrome/browser/chromeos/cros/onc_constants.h"
 #include "chrome/browser/chromeos/proxy_config_service_impl.h"
@@ skipping 1943 matching lines @@
     // on the value of AuthenticationType.
     { "L2TP-IPsec", PROVIDER_TYPE_L2TP_IPSEC_PSK },
     { "OpenVPN", PROVIDER_TYPE_OPEN_VPN },
   };
   CR_DEFINE_STATIC_LOCAL(EnumMapper<ProviderType>, parser,
       (table, arraysize(table), PROVIDER_TYPE_MAX));
   return parser.Get(type);
 }
 
 }  // namespace chromeos