Fix Loading text for settings-dropdown-menu

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

 // Copyright 2015 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 Suite of tests for settings-dropdown-menu. */
 cr.define('settings_dropdown_menu', function() {
   function registerTests() {
     suite('SettingsDropdownMenu', function() {
       /** @type {SettingsDropdownMenu} */
       var dropdown;
@@ skipping 74 matching lines @@
              {value: 'b', name: 'BBB'},
              {value: 'c', name: 'CCC'},
              {value: 'd', name: 'DDD'}];
         Polymer.dom.flush();
 
         // "Custom" initially selected.
         assertEquals(dropdown.notFoundValue_, selectable.selected);
         // Pref should not have changed.
         assertEquals('f', dropdown.pref.value);
       });
+
+      test('delay setting options', function testDelayedOptions(done) {
+        dropdown.pref = {
+          key: 'test.number2',
+          type: chrome.settingsPrivate.PrefType.NUMBER,
+          value: 200,
+        };
+

[dschuyler, 2016/08/17 23:59:46]

Would it make sense to have check that
the label is shown here and...

+        setTimeout(function() {
+          assertEquals(
+              loadTimeData.getValue('loading'), dropdown.$.dropdownMenu.label);

[dschuyler, 2016/08/17 23:59:46]

...that the label is not shown here?

I think we want the "Loading..." to be 
shown while we don't have the options
loaded and the "Loading..." to go away
when we do have the menuOptions set.

+          assertTrue(dropdown.$.dropdownMenu.disabled);
+          assertEquals(undefined, selectable.selected);
+
+          dropdown.menuOptions = [{value: 100, name: 'Option 100'},
+                                  {value: 200, name: 'Option 200'},
+                                  {value: 300, name: 'Option 300'},
+                                  {value: 400, name: 'Option 400'}];
+          Polymer.dom.flush();
+
+          // Dropdown menu enables itself and selects the new menu option
+          // correpsonding to the pref value.
+          assertFalse(dropdown.$.dropdownMenu.disabled);
+          assertEquals('200', selectable.selected);
+          done();
+        }, 100);
+      });
     });
   }
 
   return {
     registerTests: registerTests,
   };
 });