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

chrome/renderer/resources/extensions/notifications_custom_bindings.js

 // Copyright 2013 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 bindings for the notifications API.
 var binding = require('binding').Binding.create('notifications');
 
 var sendRequest = require('sendRequest').sendRequest;
 var imageUtil = require('imageUtil');
 var lastError = require('lastError');
@@ skipping 18 matching lines @@
   // |iconUrl| is required.
   var url_specs = [{
     path: notification_details.iconUrl,
     width: 80,
     height: 80,
     callback: image_data_setter(notification_details, 'iconBitmap')
   }];
 
   // |imageUrl| is optional.
   if (notification_details.imageUrl) {
-    url_specs.push({
+    $Array.push(url_specs, {
       path: notification_details.imageUrl,
       width: 360,
       height: 540,
       callback: image_data_setter(notification_details, 'imageBitmap')
     });
   }
 
   // Each button has an optional icon.
   var button_list = notification_details.buttons;
   if (button_list && typeof button_list.length === 'number') {
     var num_buttons = button_list.length;
     for (var i = 0; i < num_buttons; i++) {
       if (button_list[i].iconUrl) {
-        url_specs.push({
+        $Array.push(url_specs, {
           path: button_list[i].iconUrl,
           width: 16,
           height: 16,
           callback: image_data_setter(button_list[i], 'iconBitmap')
         });
       }
     }
   }
 
   var errors = 0;
@@ skipping 45 matching lines @@
 
 var notificationsCustomHook = function(bindingsAPI, extensionId) {
   var apiFunctions = bindingsAPI.apiFunctions;
   apiFunctions.setHandleRequest('create', handleCreate);
   apiFunctions.setHandleRequest('update', handleUpdate);
 };
 
 binding.registerCustomHook(notificationsCustomHook);
 
 exports.binding = binding.generate();