Allow comments in extension config files.

chrome/common/extensions/api/experimental.fonts.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.fontSettings",
     "types": [
       {
         "id": "FontName",
         "type": "object",
         "description": "Represents a font name.",
         "properties": {
           "fontName": {
@@ skipping 97 matching lines @@
                 "type": "array",
                 "items": { "$ref": "FontName" }
               }
             ]
           }
         ]
       }
     ]
   }
 ]