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

chrome/renderer/resources/extensions/web_view.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.
 
 // Shim that simulates a <webview> tag via Mutation Observers.
 //
 // The actual tag is implemented via the browser plugin. The internals of this
 // are hidden via Shadow DOM.
 
 var watchForTag = require('tagWatcher').watchForTag;
@@ skipping 107 matching lines @@
 
 /**
  * @private
  */
 WebView.prototype.setupWebviewNodeMethods_ = function() {
   // this.browserPluginNode_[apiMethod] are not necessarily defined immediately
   // after the shadow object is appended to the shadow root.
   var self = this;
   $Array.forEach(WEB_VIEW_API_METHODS, function(apiMethod) {
     self.webviewNode_[apiMethod] = function(var_args) {
-      return self.browserPluginNode_[apiMethod].apply(
+      return $Function.apply(self.browserPluginNode_[apiMethod],
           self.browserPluginNode_, arguments);
     };
   }, this);
   this.setupExecuteCodeAPI_();
 };
 
 /**
  * @private
  */
 WebView.prototype.setupWebviewNodeProperties_ = function() {
@@ skipping 221 matching lines @@
 
   var self = this;
   var validateCall = function() {
     if (!self.browserPluginNode_.getGuestInstanceId()) {
       throw new Error(ERROR_MSG_CANNOT_INJECT_SCRIPT);
     }
   };
 
   this.webviewNode_['executeScript'] = function(var_args) {
     validateCall();
-    var args = [self.browserPluginNode_.getGuestInstanceId()].concat(
-        Array.prototype.slice.call(arguments));
-    chrome.webview.executeScript.apply(null, args);
+    var args = $Array.concat([self.browserPluginNode_.getGuestInstanceId()],
+                             $Array.slice(arguments));
+    $Function.apply(chrome.webview.executeScript, null, args);
   }
   this.webviewNode_['insertCSS'] = function(var_args) {
     validateCall();
-    var args = [self.browserPluginNode_.getGuestInstanceId()].concat(
-        Array.prototype.slice.call(arguments));
-    chrome.webview.insertCSS.apply(null, args);
+    var args = $Array.concat([self.browserPluginNode_.getGuestInstanceId()],
+                             $Array.slice(arguments));
+    $Function.apply(chrome.webview.insertCSS, null, args);
   }
 };
 
 /**
  * Implemented when the experimental API is available.
  * @private
  */
 WebView.prototype.maybeSetupExperimentalAPI_ = function() {};
 
 exports.WebView = WebView;