Refactored extensionOptions to use the new guestViewAttributes module.

extensions/renderer/resources/guest_view/extension_options/extension_options_attributes.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 attributes of the <extensionoptions> tag.
+
+var GuestViewAttributes = require('guestViewAttributes').GuestViewAttributes;
+var ExtensionOptionsConstants =
+    require('extensionOptionsConstants').ExtensionOptionsConstants;
+var ExtensionOptionsImpl = require('extensionOptions').ExtensionOptionsImpl;
+
+// -----------------------------------------------------------------------------
+// ExtensionAttribute object.
+
+// Attribute that handles extension binded to the extensionoptions.
+function ExtensionAttribute(view) {
+  GuestViewAttributes.Attribute.call(
+      this, ExtensionOptionsConstants.ATTRIBUTE_EXTENSION, view);
+}
+
+ExtensionAttribute.prototype.__proto__ =
+    GuestViewAttributes.Attribute.prototype;
+
+ExtensionAttribute.prototype.handleMutation = function(oldValue, newValue) {
+  // We treat null attribute (attribute removed) and the empty string as
+  // one case.
+  oldValue = oldValue || '';
+  newValue = newValue || '';

[Fady Samuel, 2015/03/24 17:37:29]

This behavior is really confusing. This should behave a bit like the src
attribute of <webview>.

If we remove the extension attribute, we should add it back. Otherwise, if we
change it we should call createGuest.

[paulmeyer, 2015/03/24 18:13:40]

Done.

+
+  if (oldValue === newValue || !this.elementAttached)
+    return;
+
+  this.view.createGuest();
+};
+
+// -----------------------------------------------------------------------------
+
+// Sets up all of the extensionoptions attributes.
+ExtensionOptionsImpl.prototype.setupAttributes = function() {
+  this.attributes[ExtensionOptionsConstants.ATTRIBUTE_EXTENSION] =
+      new ExtensionAttribute(this);
+};