[MD History] Focus the search bar on load.

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

Index: chrome/test/data/webui/md_history/md_history_browsertest.js
diff --git a/chrome/test/data/webui/md_history/md_history_browsertest.js b/chrome/test/data/webui/md_history/md_history_browsertest.js
index ee4614022f86e048a937e64502cdf62f10f4612e..e3caca0eb185f845eb31cba2b742fcf18cdd3c9f 100644
--- a/chrome/test/data/webui/md_history/md_history_browsertest.js
+++ b/chrome/test/data/webui/md_history/md_history_browsertest.js
@@ -48,6 +48,13 @@ MaterialHistoryBrowserTest.prototype = {
       // Wait for the top-level app element to be upgraded.
       return waitForAppUpgrade().then(function() {
         $('history-app').queryState_.queryingDisabled = true;
+
+        // Ensure the search bar is focused on load.
+        assertTrue(
+            $('history-app')
+                .$.toolbar.$['main-toolbar']
+                .getSearchField()
+                .isSearchFocused());
       });
     });
   },