MD History: Improve dom-if usage in history-item

chrome/test/data/webui/md_history/history_item_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.
 
 cr.define('md_history.history_item_test', function() {
   function registerTests() {
     suite('history-item', function() {
       var element;
       var TEST_HISTORY_RESULTS;
       var SEARCH_HISTORY_RESULTS;
@@ skipping 63 matching lines @@
           // Checks time gap separator is removed.
           assertFalse(items[2].hasTimeGap);
         });
       });
 
       test('remove bookmarks', function() {
         element.addNewResults(TEST_HISTORY_RESULTS);
         return flush().then(function() {
           element.set('historyData_.1.starred', true);
           element.set('historyData_.5.starred', true);
+          return flush();
+        }).then(function() {
 
           items = Polymer.dom(element.root).querySelectorAll('history-item');
 
-          items[1].$['bookmark-star'].focus();
-          MockInteractions.tap(items[1].$['bookmark-star']);
+          items[1].$$('#bookmark-star').focus();
+          MockInteractions.tap(items[1].$$('#bookmark-star'));
 
           // Check that focus is shifted to overflow menu icon.
           assertEquals(items[1].root.activeElement, items[1].$['menu-button']);
           // Check that all items matching this url are unstarred.
           assertEquals(element.historyData_[1].starred, false);
           assertEquals(element.historyData_[5].starred, false);
-          assertEquals(
-              window.getComputedStyle(items[1].$['bookmark-star']).visibility,
-              'hidden');
-          assertEquals(
-              window.getComputedStyle(items[5].$['bookmark-star']).visibility,
-              'hidden');
         });
       });
 
       test('long titles are trimmed', function() {
         var item = document.createElement('history-item');
         var longtitle = '0123456789'.repeat(100);
         item.item =
             createHistoryEntry('2016-06-30', 'http://example.com/' + longtitle);
 
         var label = item.$$('history-searched-label');
         assertEquals(TITLE_MAX_LENGTH, label.title.length);
       });
 
       teardown(function() {
         element.historyData_ = [];
         element.searchedTerm = '';
       });
     });
   }
   return {
     registerTests: registerTests
   };
 });