MD Settings: Migrate startup URL action menu to settings-action-menu.

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.
  */
 
@@ skipping 18 matching lines @@
    * @param {string} url Location of an image to get a set of icons for.
    * @return {string} A set of icon URLs.
    * @private
    */
   getIconSet_: function(url) {
     return cr.icon.getFavicon(url);
   },
 
   /** @private */
   onRemoveTap_: function() {
-    this.$$('iron-dropdown').close();
+    this.$$('dialog[is=settings-action-menu]').close();
     settings.StartupUrlsPageBrowserProxyImpl.getInstance().removeStartupPage(
         this.model.modelIndex);
   },
 
   /** @private */
   onEditTap_: function() {
-    this.$$('iron-dropdown').close();
+    this.$$('dialog[is=settings-action-menu]').close();
     this.fire(settings.EDIT_STARTUP_URL_EVENT, this.model);
   },
+
+  /** @private */
+  onDotsTap_: function() {
+    var actionMenu = /** @type {!SettingsActionMenuElement} */(
+        this.$.menu.get());
+    actionMenu.showAt(assert(this.$.dots));
+  },
 });