MD Settings: add a semi-functional System page

chrome/browser/resources/settings/advanced_page/advanced_page.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.
 
 /**
  * @fileoverview
  * 'settings-advanced-page' is the settings page containing the advanced
  * settings.
  *
  * Example:
@@ skipping 21 matching lines @@
 
     /**
      * The current active route.
      */
     currentRoute: {
       type: Object,
       notify: true,
     },
   },
 
+<if expr="not chromeos">
+  listeners: {
+    'dom-change': 'onDomChange_',
+  },
+
+  /** @private */
+  onDomChange_: function() {
+    var systemPage = /** @type {?SystemPageElement} */(
+        this.$$('settings-system-page'));
+    if (systemPage && !systemPage.delegate)
+      systemPage.delegate = new settings.SystemPageDelegateImpl;
+  },
+</if>
+
   behaviors: [I18nBehavior, SettingsPageVisibility],
 });