MD Settings: adjust iron-list focus row behaviors.

chrome/browser/resources/settings/on_startup_page/startup_url_entry.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.
 
 /**
  * @fileoverview settings-startup-url-entry represents a UI component that
  * displayes a URL that is loaded during startup. It includes a menu that allows
  * the user to edit/remove the entry.
  */
 
 cr.exportPath('settings');
 
 /**
  * The name of the event fired from this element when the "Edit" option is
  * tapped.
  * @const {string}
  */
 settings.EDIT_STARTUP_URL_EVENT = 'edit-startup-url';
 
 Polymer({
   is: 'settings-startup-url-entry',
 
+  behaviors: [FocusRowBehavior],
+
   properties: {
     editable: {
       type: Boolean,
       reflectToAttribute: true,
     },
 
     /** @type {!StartupPageInfo} */
     model: Object,
   },
 
@@ skipping 23 matching lines @@
     this.fire(settings.EDIT_STARTUP_URL_EVENT, this.model);
   },
 
   /** @private */
   onDotsTap_: function() {
     var actionMenu = /** @type {!CrActionMenuElement} */(
         this.$$('#menu').get());
     actionMenu.showAt(assert(this.$$('#dots')));
   },
 });