[MD History] Focus the search bar on load.

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: {
     showSidebarFooter: Boolean,
 
@@ skipping 124 matching lines @@
   historyResult: function(info, results) {
     this.set('queryState_.querying', false);
     this.set('queryResult_.info', info);
     this.set('queryResult_.results', results);
     var listContainer =
         /** @type {HistoryListContainerElement} */ (this.$['history']);
     listContainer.historyResult(info, results);
   },
 
   /**
+   * Focuses the search bar in the toolbar.
+   */
+  focusToolbarSearchField: function() {
+    this.$.toolbar.showSearchField();
+  },
+
+  /**
    * Fired when the user presses 'More from this site'.
    * @param {{detail: {domain: string}}} e
    */
   searchDomain_: function(e) { this.$.toolbar.setSearchTerm(e.detail.domain); },
 
   /**
    * @param {Event} e
    * @private
    */
   onCanExecute_: function(e) {
@@ skipping 27 matching lines @@
   searchQueryParamChanged_: function(searchQuery) {
     this.$.toolbar.setSearchTerm(searchQuery || '');
   },
 
   /**
    * @param {Event} e
    * @private
    */
   onCommand_: function(e) {
     if (e.command.id == 'find-command' || e.command.id == 'slash-command')
-      this.$.toolbar.showSearchField();
+      this.focusToolbarSearchField();
     if (e.command.id == 'delete-command')
       this.deleteSelected();
   },
 
   /**
    * @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) {
@@ skipping 61 matching lines @@
   /**
    * This computed binding is needed to make the iron-pages selector update when
    * the synced-device-manager is instantiated for the first time. Otherwise the
    * fallback selection will continue to be used after the corresponding item is
    * added as a child of iron-pages.
    * @param {string} selectedPage
    * @param {Array} items
    * @return {string}
    * @private
    */
-  getSelectedPage_(selectedPage, items) {
+  getSelectedPage_: function(selectedPage, items) {
     return selectedPage;
   },
 
   /** @private */
   closeDrawer_: function() {
     var drawer = this.$$('#drawer');
     if (drawer)
       drawer.close();
   },
 });