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

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

Index: chrome/test/data/webui/md_history/history_toolbar_test.js
diff --git a/chrome/test/data/webui/md_history/history_toolbar_test.js b/chrome/test/data/webui/md_history/history_toolbar_test.js
index eac05b06afc833635dca7e7c9aea44a8ed37a757..cb0758212114b571e9053fc3306a6b7d85f80bf5 100644
--- a/chrome/test/data/webui/md_history/history_toolbar_test.js
+++ b/chrome/test/data/webui/md_history/history_toolbar_test.js
@@ -10,8 +10,8 @@ cr.define('md_history.history_toolbar_test', function() {
       var TEST_HISTORY_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://google.com')];
       });