cros: Fix Gaia flashing on 2nd show

chrome/browser/resources/chromeos/login/screen_gaia_signin.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.
 
 /**
  * @fileoverview Oobe signin screen implementation.
  */
 
 login.createScreen('GaiaSigninScreen', 'gaia-signin', function() {
   // GAIA animation guard timer. Started when GAIA page is loaded
@@ skipping 315 matching lines @@
       }
     },
 
     /**
      * Shows/hides loading UI.
      * @param {boolean} show True to show loading UI.
      * @private
      */
     showLoadingUI_: function(show) {
       $('gaia-loading').hidden = !show;
-      this.getSigninFrame_().hidden = show;
       this.classList.toggle('loading', show);
+      // Only set hidden for offline-gaia and not set it on the 'sign-frame'
+      // webview element. Setting it on webview not only hides but also affects
+      // its loading events.
+      if (this.isOffline)
+        this.getSigninFrame_().hidden = show;
       $('signin-frame').classList.remove('show');
       this.updateControlsState();
     },
 
     /**
      * Handler for Gaia loading timeout.
      * @private
      */
     onLoadingTimeOut_: function() {
       if (this != Oobe.getInstance().currentScreen)
@@ skipping 568 matching lines @@
       this.classList.toggle('whitelist-error', show);
       this.loading = !show;
 
       if (!show)
         Oobe.showSigninUI();
 
       this.updateControlsState();
     }
   };
 });