[MD settings] restore side nav drop icons

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;
 
     suite('SettingsMenu', function() {
       setup(function() {
         PolymerTest.clearBody();
         settingsMenu = document.createElement('settings-menu');
         document.body.appendChild(settingsMenu);
       });
 
       teardown(function() { settingsMenu.remove(); });
 
+      test('upAndDownIcons', function() {
+        // There should be different icons for a top level menu being open
+        // vs. being closed. E.g. arrow-drop-up and arrow-drop-down.
+        settingsMenu.currentRoute = {
+          page: 'advanced', section: 'reset', subpage: []
+        };
+        var ironIconElement = settingsMenu.$.advancedPage.querySelector(
+            '.menu-trigger iron-icon');
+        assertTrue(!!ironIconElement);
+        var openIcon = ironIconElement.icon;
+        assertTrue(!!openIcon);
+        // Changing to basic will close advanced.
+        settingsMenu.currentRoute = {page: 'basic', section: '', subpage: []};
+        assertNotEquals(openIcon, ironIconElement.icon);
+      });
+
       test('defaultToBasic', function() {
         settingsMenu.currentRoute = {page: 'basic', section: '', subpage: []};
         assertFalse(settingsMenu.$.advancedPage.opened);
         assertTrue(settingsMenu.$.basicPage.opened);
       });
 
       test('openAdvanced', function() {
         settingsMenu.currentRoute = {
           page: 'advanced', section: '', subpage: []
         };
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       });
     });
   }
 
   return {
     registerTests: function() {
       registerSettingsMenuTest();
     },
   };
 });