MD Settings: show restart button when user toggles metrics reporting

chrome/test/data/webui/settings/metrics_reporting_tests.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.
 
 suite('metrics reporting', function() {
   /** @type {settings.TestPrivacyPageBrowserProxy} */
   var testBrowserProxy;
 
   /** @type {SettingsPrivacyPageElement} */
   var page;
 
   setup(function() {
     testBrowserProxy = new TestPrivacyPageBrowserProxy();
     settings.PrivacyPageBrowserProxyImpl.instance_ = testBrowserProxy;
     PolymerTest.clearBody();
     page = document.createElement('settings-privacy-page');
   });
 
   teardown(function() { page.remove(); });
 
   test('changes to whether metrics reporting is enabled/managed', function() {
     return testBrowserProxy.whenCalled('getMetricsReporting').then(function() {
       Polymer.dom.flush();
+      assertFalse(!!page.$$('#metricsReporting paper-button'));
 
       var checkbox = page.$.metricsReportingCheckbox;
       assertEquals(testBrowserProxy.metricsReporting.enabled, checkbox.checked);
       var indicatorVisible = !!page.$$('#indicator');
       assertEquals(testBrowserProxy.metricsReporting.managed, indicatorVisible);
 
       var changedMetrics = {
         enabled: !testBrowserProxy.metricsReporting.enabled,
         managed: !testBrowserProxy.metricsReporting.managed,
       };
       cr.webUIListenerCallback('metrics-reporting-change', changedMetrics);
       Polymer.dom.flush();
 
+      assertTrue(!!page.$$('#metricsReporting paper-button'));
+
       assertEquals(changedMetrics.enabled, checkbox.checked);
       indicatorVisible = !!page.$$('#indicator');
       assertEquals(changedMetrics.managed, indicatorVisible);
 
       var toggled = !changedMetrics.enabled;
 
       MockInteractions.tap(checkbox);
       return testBrowserProxy.whenCalled('setMetricsReportingEnabled', toggled);
+    }).then(function() {
+      assertTrue(!!page.$$('#metricsReporting paper-button'));
     });
   });
 });