[MD History] Make forward/backward work in grouped mode.

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

Index: chrome/test/data/webui/md_history/test_util.js
diff --git a/chrome/test/data/webui/md_history/test_util.js b/chrome/test/data/webui/md_history/test_util.js
index 85eb24d8266801b35fbaa4c63b273417b3318cc3..bded27db2d98a3e45b438a9dfc25b8ec2cad45d2 100644
--- a/chrome/test/data/webui/md_history/test_util.js
+++ b/chrome/test/data/webui/md_history/test_util.js
@@ -9,8 +9,12 @@
  */
 function replaceBody(element) {
   var body = document.body;
-  var currentBody =
-      body.querySelector('history-app') || body.querySelector('.test-body');
+  var app = body.querySelector('history-app');
+  // Clear the query on the app, if it exists. This clears any query in the URL.
+  if (app)
+    app.set('queryState_.searchTerm', '');
+
+  var currentBody = app || body.querySelector('.test-body');
   body.removeChild(currentBody);
 
   element.classList.add('test-body');