Use browsers JSON.parse for parsing JSON.

runtime/bin/json_sources.gypi

Index: runtime/bin/json_sources.gypi
diff --git a/runtime/bin/json_sources.gypi b/runtime/bin/json_sources.gypi
index 6c9ca3d32d704aea8745f5fcf2fde0d8d2076cfe..38bb9831e024fd98eb0711ad8c6759ec01b6d320 100644
--- a/runtime/bin/json_sources.gypi
+++ b/runtime/bin/json_sources.gypi
@@ -1,10 +1,10 @@
-# Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+# Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
-# This file contains all sources for the dart:io library.
+# This file contains all runtime-specific sources for the dart:json library.
 {
   'sources': [
-    '../../sdk/lib/json/json.dart',
+    'json_patch.dart',
   ],
 }