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

chrome/renderer/resources/extensions/app_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 app API.
 
 var GetAvailability = requireNative('v8_context').GetAvailability;
 if (!GetAvailability('app').is_available) {
   exports.chromeApp = {};
   exports.onInstallStateResponse = function(){};
   return;
 }
 
 var appNatives = requireNative('app');
 var process = requireNative('process');
 var extensionId = process.GetExtensionId();
 var logActivity = requireNative('activityLogger');
 
 function wrapForLogging(fun) {
   var id = extensionId;
   return (function() {
     // TODO(ataly): We need to make sure we use the right prototype for
     // fun.apply. Array slice can either be rewritten or similarly defined.
     logActivity.LogAPICall(id, "app." + fun.name,
-        Array.prototype.slice.call(arguments));
-    return fun.apply(this, arguments);
+        $Array.slice(arguments));
+    return $Function.apply(fun, this, arguments);
   });
 }
 
 // This becomes chrome.app
 var app;
 if (!extensionId) {
   app = {
     getIsInstalled: appNatives.GetIsInstalled,
     getDetails: appNatives.GetDetails,
     getDetailsForFrame: appNatives.GetDetailsForFrame,
@@ skipping 37 matching lines @@
   callbacks[callbackId] = callback;
   appNatives.GetInstallState(callbackId);
 };
 if (extensionId)
   app.installState = wrapForLogging(app.installState);
 
 // This must match InstallAppBindings() in
 // chrome/renderer/extensions/dispatcher.cc.
 exports.chromeApp = app;
 exports.onInstallStateResponse = onInstallStateResponse;