preload polymer elements in options page

chrome/browser/resources/options/chromeos/quick_unlock_configure_overlay.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.
 
 cr.define('options', function() {
   var Page = cr.ui.pageManager.Page;
   var PageManager = cr.ui.pageManager.PageManager;
 
   /**
    * QuickUnlockConfigureOverlay class
@@ skipping 12 matching lines @@
 
   QuickUnlockConfigureOverlay.prototype = {
     __proto__: Page.prototype,
 
     /** @override */
     initializePage: function() {
       Page.prototype.initializePage.call(this);
       $('screen-lock-done').onclick = function() {
         QuickUnlockConfigureOverlay.dismiss();
       };
+
+      if (loadTimeData.getBoolean('enablePolymerPreload'))
+        requestIdleCallback(this.ensurePolymerIsLoaded_.bind(this));
     },
 
     /** @override */
     didClosePage: function() {
       settings.navigateTo(settings.Route.PEOPLE);
     },
 
     /** @override */
     didShowPage: function() {
       this.ensurePolymerIsLoaded_().then(this.onPolymerLoaded_.bind(this));
@@ skipping 44 matching lines @@
 
   QuickUnlockConfigureOverlay.dismiss = function() {
     PageManager.closeOverlay();
   };
 
   // Export
   return {
     QuickUnlockConfigureOverlay: QuickUnlockConfigureOverlay
   };
 });