Allow comments in extension config files.

chrome/common/extensions/api/input.ime.json

+// 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.
+
 [
   {
     "namespace": "input.ime",
     "platforms": ["chromeos"],
     "types": [
       {
         "id": "KeyboardEvent",
         "type": "object",
         "description": "See http://www.w3.org/TR/DOM-Level-3-Events/#events-KeyboardEvent",
         "properties": {
@@ skipping 507 matching lines @@
           {
             "type": "string",
             "name": "name",
             "description": "Name of the MenuItem which was activated"
           }
         ]
       }
     ]
   }
 ]