Allow comments in extension config files.

chrome/common/extensions/api/metricsPrivate.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": "metricsPrivate",
     "nodoc": true,
     "types": [
       {
         "id": "MetricType",
         "type":  "object",
         "description": "Describes the type of metric that is to be collected.",
         "properties": {
@@ skipping 87 matching lines @@
         "description": "Adds a value to the given metric.",
         "parameters": [
           {"name": "metric", "$ref": "MetricType"},
           {"name": "value", "type": "integer"}
         ]
       }
     ],
     "events": []
   }
 ]