Prevent signin frame size update at first login

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 680 matching lines @@
      * Displays correct screen container for given mode and APi version.
      */
     updateSigninFrameContainers_: function() {
       let old_state = this.classList.contains('v2');
       this.classList.toggle('v2', false);
       if ((this.screenMode_ == ScreenMode.DEFAULT ||
            this.screenMode_ == ScreenMode.OFFLINE) &&
           this.chromeOSApiVersion_ == 2) {
         this.classList.toggle('v2', true);
       }
+      if (this != Oobe.getInstance().currentScreen)
+        return;
       // Switching between signin-frame-dialog and gaia-step-contents
       // updates screen size.
       if (old_state != this.classList.contains('v2'))
         Oobe.getInstance().updateScreenSize(this);
     },
 
     /**
      * Whether the current auth flow is SAML.
      */
     isSAML: function() {
@@ skipping 463 matching lines @@
       if (this.screenMode_ != ScreenMode.AD_AUTH)
         return;
       var adAuthUI = this.getSigninFrame_();
       adAuthUI.setUser(username);
       adAuthUI.setInvalid(errorState);
       this.loading = false;
       Oobe.getInstance().headerHidden = false;
     }
   };
 });