MD History: Fix forward slash key not working in search field

chrome/browser/resources/md_history/app.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.
 
 Polymer({
   is: 'history-app',
 
   properties: {
     // The id of the currently selected page.
     selectedPage_: {type: String, value: 'history', observer: 'unselectAll'},
@@ skipping 100 matching lines @@
    * Fired when the user presses 'More from this site'.
    * @param {{detail: {domain: string}}} e
    */
   searchDomain_: function(e) { this.$.toolbar.setSearchTerm(e.detail.domain); },
 
   /**
    * @param {Event} e
    * @private
    */
   onCanExecute_: function(e) {
-    e.canExecute = true;
+    e = /** @type {cr.ui.CanExecuteEvent} */(e);
+    switch (e.command.id) {
+      case 'find-command':
+        e.canExecute = true;
+        break;
+      case 'slash-command':
+        e.canExecute =
+            !(this.$.toolbar.searchBar.showingSearch &&
+              this.$.toolbar.searchBar.isSearchFocused());
+        break;
+    }
   },
 
   /**
    * @param {Event} e
    * @private
    */
   onCommand_: function(e) {
-    if (e.command.id == 'find-command')
+    if (e.command.id == 'find-command' || e.command.id == 'slash-command')
       this.$.toolbar.showSearchField();
   },
 
   /**
    * @param {!Array<!ForeignSession>} sessionList Array of objects describing
    *     the sessions from other devices.
    * @param {boolean} isTabSyncEnabled Is tab sync enabled for this profile?
    */
   setForeignSessions: function(sessionList, isTabSyncEnabled) {
     if (!isTabSyncEnabled)
@@ skipping 27 matching lines @@
    * @param {boolean} incremental
    * @param {string} searchTerm
    * @return {boolean} Whether a loading spinner should be shown (implies the
    *     backend is querying a new search term).
    * @private
    */
   shouldShowSpinner_: function(querying, incremental, searchTerm) {
     return querying && !incremental && searchTerm != '';
   },
 });