MD Settings: Restore focus after closing dialogs, for startup page.

chrome/browser/resources/settings/on_startup_page/startup_urls_page.js

 // Copyright 2015 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-urls-page' is the settings page
  * containing the urls that will be opened when chrome is started.
  */
 
 Polymer({
@@ skipping 16 matching lines @@
     /** @private */
     showStartupUrlDialog_: Boolean,
 
     /** @private {?StartupPageInfo} */
     startupUrlDialogModel_: Object,
 
     /** @private {Object}*/
     lastFocused_: Object,
   },
 
+  /**
+   * The element to return focus to, when the startup-url-dialog is closed.
+   * @private {?HTMLElement}
+   */
+  startupUrlDialogAnchor_: null,
+
   /** @override */
   attached: function() {
     this.browserProxy_ = settings.StartupUrlsPageBrowserProxyImpl.getInstance();
     this.addWebUIListener('update-startup-pages', function(startupPages) {
       // If an "edit" URL dialog was open, close it, because the underlying page
       // might have just been removed (and model indices have changed anyway).
       if (this.startupUrlDialogModel_)
         this.destroyUrlDialog_();
       this.startupPages_ = startupPages;
       this.updateScrollableContents();
     }.bind(this));
     this.browserProxy_.loadStartupPages();
 
     this.addEventListener(settings.EDIT_STARTUP_URL_EVENT, function(event) {
-      this.startupUrlDialogModel_ = event.detail;
+      this.startupUrlDialogModel_ = event.detail.model;
+      this.startupUrlDialogAnchor_ = event.detail.anchor;
       this.showStartupUrlDialog_ = true;
       event.stopPropagation();
     }.bind(this));
   },
 
   /**
    * @param {!Event} e
    * @private
    */
   onAddPageTap_: function(e) {
     e.preventDefault();
     this.showStartupUrlDialog_ = true;
+    this.startupUrlDialogAnchor_ = /** @type {!HTMLElement} */ (
+        this.$$('#addPage a[is=action-link]'));
   },
 
   /** @private */
   destroyUrlDialog_: function() {
     this.showStartupUrlDialog_ = false;
     this.startupUrlDialogModel_ = null;
+    if (this.startupUrlDialogAnchor_) {
+      this.startupUrlDialogAnchor_.focus();
+      this.startupUrlDialogAnchor_ = null;
+    }
   },
 
   /** @private */
   onUseCurrentPagesTap_: function() {
     this.browserProxy_.useCurrentPages();
   },
 });