Allow comments in extension config files.

chrome/common/extensions/api/permissions.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": "permissions",
     "types": [
       {
         "id": "Permissions",
         "type": "object",
         "properties": {
           "permissions": {
             "type": "array",
@@ skipping 119 matching lines @@
                 "type": "boolean",
                 "description": "True if the permissions were removed."
               }
             ]
           }
         ]
       }
     ]
   }
 ]