Extract the element implementation logic to function mods in <webview>.

extensions/renderer/resources/guest_view/extension_view/extension_view.js

 // Copyright 2015 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.
 
 // This module implements the ExtensionView <extensionview>.
 
 var GuestViewContainer = require('guestViewContainer').GuestViewContainer;
 var ExtensionViewConstants =
     require('extensionViewConstants').ExtensionViewConstants;
 var ExtensionViewEvents = require('extensionViewEvents').ExtensionViewEvents;
@@ skipping 11 matching lines @@
 ExtensionViewImpl.VIEW_TYPE = 'ExtensionView';
 
 ExtensionViewImpl.setupElement = function(proto) {
   var apiMethods = ExtensionViewImpl.getApiMethods();
 
   GuestViewContainer.forwardApiMethods(proto, apiMethods);
 };
 
 ExtensionViewImpl.prototype.createGuest = function() {
   this.guest.create(this.buildParams(), function() {
-    this.attachWindow();
+    this.attachWindow$();
   }.bind(this));
 };
 
 ExtensionViewImpl.prototype.buildContainerParams = function() {
   var params = {};
   for (var i in this.attributes) {
     params[i] = this.attributes[i].getValue();
   }
   return params;
 };
@@ skipping 10 matching lines @@
 // Updates src upon loadcommit.
 ExtensionViewImpl.prototype.onLoadCommit = function(url) {
   this.attributes[ExtensionViewConstants.ATTRIBUTE_SRC].
       setValueIgnoreMutation(url);
 };
 
 GuestViewContainer.registerElement(ExtensionViewImpl);
 
 // Exports.
 exports.ExtensionViewImpl = ExtensionViewImpl;