Refactored the attributes modules of extension_view and web_view into guest_view_attributes.js.

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 39 matching lines @@
 
   // Let the changed attribute handle its own mutation.
   this.attributes[attributeName].maybeHandleMutation(oldValue, newValue);
 };
 
 ExtensionViewImpl.prototype.onElementDetached = function() {
   this.guest.destroy();
 
   // Reset all attributes.
   for (var i in this.attributes) {
-    this.attributes[i].reset();
+    this.attributes[i].setValueIgnoreMutation();
   }
 };
 
 // Updates src upon loadcommit.
 ExtensionViewImpl.prototype.onLoadCommit = function(url) {
   this.attributes[ExtensionViewConstants.ATTRIBUTE_SRC].
       setValueIgnoreMutation(url);
 };
 
 GuestViewContainer.registerElement(ExtensionViewImpl);
 
 // Exports.
 exports.ExtensionViewImpl = ExtensionViewImpl;