[Extensions] More bindings hardening

chrome/renderer/resources/extensions/chrome_setting.js

 // 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.
 
 var Event = require('event_bindings').Event;
 var sendRequest = require('sendRequest').sendRequest;
 var validate = require('schemaUtils').validate;
 
 function extendSchema(schema) {
   var extendedSchema = $Array.slice(schema);
@@ skipping 21 matching lines @@
   this.clear = function(details, callback) {
     var clearSchema = this.functionSchemas.clear.definition.parameters;
     validate([details, callback], clearSchema);
     return sendRequest('types.ChromeSetting.clear',
                        [prefKey, details, callback],
                        extendSchema(clearSchema));
   };
   this.onChange = new Event('types.ChromeSetting.' + prefKey + '.onChange');
 };
 
-exports.ChromeSetting = ChromeSetting;
+exports.$set('ChromeSetting', ChromeSetting);