[MD settings] restore side nav drop icons

chrome/test/data/webui/settings/settings_menu_test.js

Index: chrome/test/data/webui/settings/settings_menu_test.js
diff --git a/chrome/test/data/webui/settings/settings_menu_test.js b/chrome/test/data/webui/settings/settings_menu_test.js
index 0a090fc0eb16d67ce08d2c4046e632c4930118c3..f2a3f0022168fafe6e8b4bc8f75ea134f0e38ba9 100644
--- a/chrome/test/data/webui/settings/settings_menu_test.js
+++ b/chrome/test/data/webui/settings/settings_menu_test.js
@@ -17,6 +17,22 @@ cr.define('settings_menu', function() {
 
       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);