Add a blocking version of the sync promo dialog

chrome/browser/resources/sync_promo/sync_promo.js

 // Copyright (c) 2012 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.
 
 // TODO(sail): Refactor options_page and remove this include.
 <include src="../options/options_page.js"/>
 <include src="../sync_setup_overlay.js"/>
 
 cr.define('sync_promo', function() {
   /**
@@ skipping 127 matching lines @@
       $('confirm-everything-cancel').addEventListener('click', cancelFunc);
       $('choose-datatypes-cancel').addEventListener('click', cancelFunc);
 
       this.infographic_ = $('promo-infographic');
       this.learnMore_ = $('promo-information');
 
       this.infographic_.addEventListener('webkitTransitionEnd',
                                          this.toggleHidden_.bind(this));
       this.learnMore_.addEventListener('webkitTransitionEnd',
                                        this.toggleHidden_.bind(this));
+
+      document.body.classList.add('loaded');
     },
 
     /**
      * Called when the page is unloading to record number of times a user tried
      * to sign in and if they left while a throbber was running.
      * @private
      */
     recordPageViewActions_: function() {
       chrome.send('SyncPromo:RecordSignInAttempts', [this.signInAttempts_]);
       if (this.throbberStart_)
@@ skipping 124 matching lines @@
   return {
     SyncPromo: SyncPromo
   };
 });
 
 var OptionsPage = options.OptionsPage;
 var SyncSetupOverlay = sync_promo.SyncPromo;
 window.addEventListener('DOMContentLoaded', sync_promo.SyncPromo.initialize);
 window.addEventListener('beforeunload',
     sync_promo.SyncPromo.recordPageViewActions.bind(sync_promo.SyncPromo));