Allow comments in extension config files.

chrome/common/extensions/api/experimental.processes.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.processes",
     "nodoc": true,
     "types": [
       {
         "id": "Process",
         "type": "object",
         "description": "An object containing information about one of the browser's processes.",
         "properties": {
@@ skipping 59 matching lines @@
           {
             "name": "processes",
             "type": "object",
             "additionalProperties": { "$ref": "Process" }
           }
         ]
       }
     ]
   }
 ]