MD History: Add lazy-render element for simple lazy initialization.

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 19 matching lines @@
     'test_util.js',
     'browser_service_test.js',
     'history_drawer_test.js',
     'history_grouped_list_test.js',
     'history_item_test.js',
     'history_list_test.js',
     'history_overflow_menu_test.js',
     'history_routing_test.js',
     'history_supervised_user_test.js',
     'history_synced_tabs_test.js',
-    'history_toolbar_test.js'
+    'history_toolbar_test.js',
+    'lazy_render_test.js'
   ]),
 
   /** @override */
   setUp: function() {
     PolymerTest.prototype.setUp.call(this);
 
     suiteSetup(function() {
       // Wait for the top-level app element to be upgraded.
       return waitForAppUpgrade().then(function() {
         $('history-app').queryState_.queryingDisabled = true;
@@ skipping 30 matching lines @@
 TEST_F('MaterialHistoryBrowserTest', 'HistoryToolbarTest', function() {
   md_history.history_toolbar_test.registerTests();
   mocha.run();
 });
 
 TEST_F('MaterialHistoryBrowserTest', 'HistoryOverflowMenuTest', function() {
   md_history.history_overflow_menu_test.registerTests();
   mocha.run();
 });
 
+TEST_F('MaterialHistoryBrowserTest', 'LazyRenderTest', function() {
+  md_history.lazy_render_test.registerTests();
+  mocha.run();
+});
+
 TEST_F('MaterialHistoryBrowserTest', 'RoutingTest', function() {
   md_history.history_routing_test.registerTests();
   mocha.run();
 });
 
 TEST_F('MaterialHistoryBrowserTest', 'SyncedTabsTest', function() {
   md_history.history_synced_tabs_test.registerTests();
   mocha.run();
 });
 
@@ skipping 40 matching lines @@
       return waitForAppUpgrade();
     });
   },
 };
 
 TEST_F('MaterialHistoryWithQueryParamTest', 'RoutingTestWithQueryParam',
   function() {
     md_history.history_routing_test_with_query_param.registerTests();
     mocha.run();
 });