Allow comments in extension config files.

chrome/common/extensions/api/idle.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": "idle",
     "types": [],
     "functions": [
       {
         "name": "queryState",
         "type": "function",
         "description": "Returns the current state of the browser.",
         "parameters": [
@@ skipping 26 matching lines @@
           {
             "name": "newState",
             "type": "string",
             "enum": ["active"]
           }
         ]
       }
     ]
   }
 ]