MD History: focus REMOVE button by default in multi-delete dialog

chrome/browser/resources/md_history/list_container.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-list-container',
 
   properties: {
     // The path of the currently selected page.
     selectedPage_: String,
@@ skipping 118 matching lines @@
    */
   deleteSelectedWithPrompt: function() {
     if (!loadTimeData.getBoolean('allowDeletingHistory'))
       return;
 
     var browserService = md_history.BrowserService.getInstance();
     browserService.recordAction('RemoveSelected');
     if (this.queryState.searchTerm != '')
       browserService.recordAction('SearchResultRemove');
     this.$.dialog.get().showModal();
+
+    // TODO(dbeam): remove focus flicker caused by showModal() + focus().
+    this.$$('.action-button').focus();
   },
 
   /**
    * @param {HistoryRange} range
    * @private
    */
   groupedRangeChanged_: function(range, oldRange) {
     this.selectedPage_ = range == HistoryRange.ALL_TIME ?
       'infinite-list' : 'grouped-list';
 
@@ skipping 121 matching lines @@
         }.bind(this));
     menu.closeMenu();
   },
 
   /**
    * @return {HTMLElement}
    * @private
    */
   getSelectedList_: function() { return this.$.content.selectedItem; },
 });