[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..3b5e094feefdf992b9068f22a9a19714f4c90064 100644
--- a/chrome/test/data/webui/settings/settings_menu_test.js
+++ b/chrome/test/data/webui/settings/settings_menu_test.js
@@ -17,6 +17,23 @@ 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');

[dpapad, 2016/05/05 21:13:48]

Nit: Let's assert that the element was actually found before making further
assertions.
assertTrue(!!ironIconElement);

[dschuyler, 2016/05/05 21:19:21]

Done.

+        var openIcon = ironIconElement.icon;
+        assertTrue(!!openIcon);
+        // Changing to basic will close advanced.
+        settingsMenu.currentRoute = {
+          page: 'basic', section: 'reset', subpage: []

[dpapad, 2016/05/05 21:13:48]

Nit: basic page does not have a 'reset' section, maybe replace 'reset' with an
existing section?

[dschuyler, 2016/05/05 21:19:21]

Done.

+        };
+        assertNotEquals(openIcon, ironIconElement.icon);
+      });
+
       test('defaultToBasic', function() {
         settingsMenu.currentRoute = {page: 'basic', section: '', subpage: []};
         assertFalse(settingsMenu.$.advancedPage.opened);