Allow comments in extension config files.

chrome/common/extensions/api/webSocketProxyPrivate.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": "webSocketProxyPrivate",
     "nodoc": true,
     "types": [],
     "functions": [
       {
         "name": "getPassportForTCP",
         "description": "requests authorization token for websocket to TCP proxy.",
         "parameters": [
@@ skipping 58 matching lines @@
                 "description": "URL for opening as WebSocket."
               }
             ]
           }
         ]
       }
     ],
     "events": []
   }
 ]