MD History: Update timestamp hover text when item changes

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.
 
 var TEST_HISTORY_RESULTS = [
   createHistoryEntry('2016-03-16 10:00', 'http://www.google.com'),
   createHistoryEntry('2016-03-16 9:00', 'http://www.example.com'),
   createHistoryEntry('2016-03-16 7:01', 'http://www.badssl.com'),
   createHistoryEntry('2016-03-16 7:00', 'http://www.website.com'),
   createHistoryEntry('2016-03-16 4:00', 'http://www.website.com'),
@@ skipping 36 matching lines @@
 
   test('refocus checkbox on click', function() {
     return PolymerTest.flushTasks().then(function() {
       item.$['menu-button'].focus();
       assertEquals(item.$['menu-button'], item.root.activeElement);
 
       MockInteractions.tap(item.$['time-accessed']);
       assertEquals(item.$['checkbox'], item.root.activeElement);
     });
   });
+
+  test('title changes with item', function() {
+    var time = item.$['time-accessed'];
+    assertEquals('', time.title);
+
+    time.dispatchEvent(new CustomEvent('mouseover'));
+    var initialTitle = time.title;
+    item.item = TEST_HISTORY_RESULTS[5];
+    time.dispatchEvent(new CustomEvent('mouseover'));
+    assertNotEquals(initialTitle, time.title);
+  });
 });
 
 suite('<history-item> integration test', function() {
   var element;
 
   setup(function() {
     element = replaceApp().$.history;
   });
 
   test('basic separator insertion', function() {
@@ skipping 56 matching lines @@
       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);
     });
   });
 });