Allow comments in extension config files.

chrome/common/extensions/api/experimental.accessibility.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": "experimental.accessibility",
     "nodoc": true,
     "types": [
       {
         "id": "AccessibilityObject",
         "type": "object",
         "description": "Parent class for accessibility information about an object.",
         "properties": {
@@ skipping 253 matching lines @@
           {
             "$ref": "AccessibilityObject",
             "name": "menu",
             "description": "Information about the menu that was closed."
           }
         ]
       }
     ]
   }
 ]