Fix issue where side nav wasn't updated every time the route changed.

chrome/test/data/webui/settings/settings_menu_test.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.
 
 /** @fileoverview Runs tests for the settings menu. */
 
 cr.define('settings_menu', function() {
   function registerSettingsMenuTest() {
     var settingsMenu = null;
 
@@ skipping 69 matching lines @@
         document.body.appendChild(settingsMenu);
       });
 
       teardown(function() { settingsMenu.remove(); });
 
       test('openResetSection', function() {
         var selector = settingsMenu.$.subMenu;
         var path = new window.URL(selector.selected).pathname;
         assertEquals('/reset', path);
       });
+
+      test('navigateToAnotherSection', function() {
+        var selector = settingsMenu.$.subMenu;
+        var path = new window.URL(selector.selected).pathname;
+        assertEquals('/reset', path);
+
+        settings.navigateTo(settings.Route.PEOPLE, '');
+        Polymer.dom.flush();
+
+        path = new window.URL(selector.selected).pathname;
+        assertEquals('/people', path);
+      });
+
+      test('navigateToBasic', function() {
+        var selector = settingsMenu.$.subMenu;
+        var path = new window.URL(selector.selected).pathname;
+        assertEquals('/reset', path);
+
+        settings.navigateTo(settings.Route.BASIC, '');
+        Polymer.dom.flush();
+
+        // BASIC has no sub page selected.
+        assertFalse(!!selector.selected);
+      });
     });
   }
 
   return {
     registerTests: function() {
       registerSettingsMenuTest();
     },
   };
 });