MD Settings: Lazy load the contents of the "advanced" settings.

chrome/browser/resources/settings/route.js

 // Copyright 2016 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.
 
 cr.define('settings', function() {
   /**
    * Class for navigable routes. May only be instantiated within this file.
    * @constructor
    * @param {string} path
    * @private
    */
   var Route = function(path) {
     this.path = path;
 
     /** @type {?settings.Route} */
     this.parent = null;
 
     /** @type {number} */
     this.depth = 0;
 
+    /**
+     * @type {boolean} Whether this route corresponds to a navigable
+     *     dialog. Those routes don't belong to a "section".
+     */
+    this.isNavigableDialog = false;
+
     // Below are all legacy properties to provide compatibility with the old
-    // routing system. TODO(tommycli): Remove once routing refactor complete.
+    // routing system.
+
+    /** @type {string} */
     this.section = '';
   };
 
   Route.prototype = {
     /**
      * Returns a new Route instance that's a child of this route.
      * @param {string} path Extends this route's path if it doesn't contain a
      *     leading slash.
      * @return {!settings.Route}
      * @private
@@ skipping 54 matching lines @@
   var r = Route;
 
   // Root pages.
   r.BASIC = new Route('/');
   r.ADVANCED = new Route('/advanced');
   r.ABOUT = new Route('/help');
 
   // Navigable dialogs. These are the only non-section children of root pages.
   // These are disfavored. If we add anymore, we should add explicit support.
   r.IMPORT_DATA = r.BASIC.createChild('/importData');
+  r.IMPORT_DATA.isNavigableDialog = true;
   r.SIGN_OUT = r.BASIC.createChild('/signOut');
+  r.SIGN_OUT.isNavigableDialog = true;
   r.CLEAR_BROWSER_DATA = r.ADVANCED.createChild('/clearBrowserData');
+  r.CLEAR_BROWSER_DATA.isNavigableDialog = true;
   r.RESET_DIALOG = r.ADVANCED.createChild('/resetProfileSettings');
+  r.RESET_DIALOG.isNavigableDialog = true;
   r.TRIGGERED_RESET_DIALOG =
       r.ADVANCED.createChild('/triggeredResetProfileSettings');
+  r.TRIGGERED_RESET_DIALOG.isNavigableDialog = true;
 
 // <if expr="chromeos">
   r.INTERNET = r.BASIC.createSection('/internet', 'internet');
   r.INTERNET_NETWORKS = r.INTERNET.createChild('/networks');
   r.NETWORK_DETAIL = r.INTERNET.createChild('/networkDetail');
   r.KNOWN_NETWORKS = r.INTERNET.createChild('/knownNetworks');
   r.BLUETOOTH = r.BASIC.createSection('/bluetooth', 'bluetooth');
   r.BLUETOOTH_DEVICES = r.BLUETOOTH.createChild('/bluetoothDevices');
 // </if>
 
@@ skipping 291 matching lines @@
     getRouteForPath: getRouteForPath,
     initializeRouteFromUrl: initializeRouteFromUrl,
     resetRouteForTesting: resetRouteForTesting,
     getCurrentRoute: getCurrentRoute,
     getQueryParameters: getQueryParameters,
     lastRouteChangeWasPopstate: lastRouteChangeWasPopstate,
     navigateTo: navigateTo,
     navigateToPreviousRoute: navigateToPreviousRoute,
   };
 });