MD History: add shortcuts for search

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

 // Copyright 2016 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.
 
 cr.define('md_history.history_toolbar_test', function() {
   function registerTests() {
     suite('history-toolbar', function() {
       var app;
       var element;
       var toolbar;
@@ skipping 34 matching lines @@
       test('search term gathered correctly from toolbar', function(done) {
         app.queryState_.queryingDisabled = false;
         registerMessageCallback('queryHistory', this, function (info) {
           assertEquals(info[0], 'Test');
           done();
         });
 
         toolbar.$$('cr-toolbar').fire('search-changed', 'Test');
       });
 
+      test('shortcuts to open search field', function() {
+        var field = toolbar.$['main-toolbar'].getSearchField();
+        assertFalse(field.showingSearch);
+
+        MockInteractions.pressAndReleaseKeyOn(
+            field.$.searchInput, 191, '', '/');

[tsergeant, 2016/07/08 00:26:05]

In MockInteractions.pressAndReleaseKeyOn, it's probably better to not target
`field.$.searchInput`, since that's kind of like saying that the events will
work if the search input is already focused.

It's better to check that the events can be fired from anywhere on the document
and still work:

MockInteractions.pressAndReleaseKeyOn(document, 191, ...)

[lshang, 2016/07/08 05:37:24]

Done.

+        assertTrue(field.showingSearch);
+        assertEquals(field.$.searchInput, field.root.activeElement);
+
+        MockInteractions.pressAndReleaseKeyOn(
+            field.$.searchInput, 27, '', 'Escape');
+        assertFalse(field.showingSearch, 'Pressing escape closes field.');
+        assertNotEquals(field.$.searchInput, field.root.activeElement);
+
+        MockInteractions.pressAndReleaseKeyOn(

[tsergeant, 2016/07/08 00:26:05]

As above, use document here.

[lshang, 2016/07/08 05:37:24]

Done.

+            field.$.searchInput, 70, 'ctrl', 'f');
+        assertTrue(field.showingSearch);
+        assertEquals(field.$.searchInput, field.root.activeElement);
+     });
+
       teardown(function() {
         element.historyData_ = [];
         element.searchedTerm = '';
         registerMessageCallback('queryHistory', this, undefined);
         toolbar.count = 0;
       });
     });
   }
   return {
     registerTests: registerTests
   };
 });