Revert of Disable MaterialHistoryBrowserTest.HistoryListTest since

chrome/test/data/webui/md_history/md_history_browsertest.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 Test suite for the Material Design history page.
  */
 
 var ROOT_PATH = '../../../../../';
 
@@ skipping 68 matching lines @@
 TEST_F('MaterialHistoryBrowserTest', 'HistoryGroupedListTest', function() {
   md_history.history_grouped_list_test.registerTests();
   mocha.run();
 });
 
 TEST_F('MaterialHistoryBrowserTest', 'HistoryItemTest', function() {
   md_history.history_item_test.registerTests();
   mocha.run();
 });
 
-// Flaky on chromeos, http://crbug.com/640862
-TEST_F('MaterialHistoryBrowserTest', 'DISABLED_HistoryListTest', function() {
+TEST_F('MaterialHistoryBrowserTest', 'HistoryListTest', function() {
   md_history.history_list_test.registerTests();
   mocha.run();
 });
 
 TEST_F('MaterialHistoryBrowserTest', 'Metrics', function() {
   md_history.history_metrics_test.registerTests();
   mocha.run();
 });
 
 TEST_F('MaterialHistoryBrowserTest', 'HistoryToolbarTest', function() {
@@ skipping 65 matching lines @@
       });
     });
   },
 };
 
 TEST_F('MaterialHistoryWithQueryParamTest', 'RoutingTestWithQueryParam',
   function() {
     md_history.history_routing_test_with_query_param.registerTests();
     mocha.run();
 });