MD Settings: Lazy-load sub-pages.

chrome/browser/resources/settings/settings_page/settings_subheader.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-subheader' shows a subheader for subpages. This header contains
- * the subpage title and a back icon. The back icon fires an event which
- * is caught by settings-animated-pages, so it requires no separate handling.
- *
- * Examples:
- *
- *    <settings-subheader i18n-values="page-title:internetPageTitle">
- *    </settings-subheader>
- */
-Polymer({
-  is: 'settings-subheader',
-
-  /** @private */
-  onTapBack_: function() {
-    // Event is caught by settings-animated-pages.
-    this.fire('subpage-back');
-  },
-});