Make the externally connectable browser test clobber all of the builtins,

chrome/renderer/resources/extensions/declarative_webrequest_custom_bindings.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.
 
 // Custom binding for the declarativeWebRequest API.
 
 var binding = require('binding').Binding.create('declarativeWebRequest');
 
 var utils = require('utils');
 var validate = require('schemaUtils').validate;
 
 binding.registerCustomHook(function(api) {
   var declarativeWebRequest = api.compiledApi;
 
   // Returns the schema definition of type |typeId| defined in |namespace|.
   function getSchema(typeId) {
     return utils.lookup(api.schema.types,
                         'id',
                         'declarativeWebRequest.' + typeId);
   }
 
   // Helper function for the constructor of concrete datatypes of the
   // declarative webRequest API.
   // Makes sure that |this| contains the union of parameters and
   // {'instanceType': 'declarativeWebRequest.' + typeId} and validates the
   // generated union dictionary against the schema for |typeId|.
   function setupInstance(instance, parameters, typeId) {
     for (var key in parameters) {
-      if (parameters.hasOwnProperty(key)) {
+      if ($Object.hasOwnProperty(parameters, key)) {
         instance[key] = parameters[key];
       }
     }
     instance.instanceType = 'declarativeWebRequest.' + typeId;
     var schema = getSchema(typeId);
     validate([instance], [schema]);
   }
 
   // Setup all data types for the declarative webRequest API.
   declarativeWebRequest.RequestMatcher = function(parameters) {
@@ skipping 47 matching lines @@
   };
   declarativeWebRequest.RemoveResponseCookie = function(parameters) {
     setupInstance(this, parameters, 'RemoveResponseCookie');
   };
   declarativeWebRequest.SendMessageToExtension = function(parameters) {
     setupInstance(this, parameters, 'SendMessageToExtension');
   };
 });
 
 exports.binding = binding.generate();