[MD History] Refactor history.html into a history-app element.

chrome/test/data/webui/md_history/history_list_test.js

Index: chrome/test/data/webui/md_history/history_list_test.js
diff --git a/chrome/test/data/webui/md_history/history_list_test.js b/chrome/test/data/webui/md_history/history_list_test.js
index 005c61923b6827d29f116b3bb4e1a7d8a6f33a26..b6d5b8b2962c782737c7da1a8f882b80bc268473 100644
--- a/chrome/test/data/webui/md_history/history_list_test.js
+++ b/chrome/test/data/webui/md_history/history_list_test.js
@@ -11,8 +11,8 @@ cr.define('md_history.history_list_test', function() {
       var ADDITIONAL_RESULTS;
 
       suiteSetup(function() {
-        element = $('history-list');
-        toolbar = $('toolbar');
+        element = $('history-app').$['history-list'];
+        toolbar = $('history-app').$['toolbar'];
 
         TEST_HISTORY_RESULTS = [
           createHistoryEntry('2016-03-15', 'https://www.google.com'),