Remove -webkit-*-before/after in:

chrome/browser/resources/chromeos/login/screen_gaia_signin.css

 /* 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.
  */
 
 #gaia-signin {
   height: 609px; /* Should be the same as #user-image.loading min-heigth. */
   padding: 70px 17px 69px;    /* Screen has no controls. */
   width: 722px; /* Should be the same as #user-image.loading width. */
 }
 
 #gaia-signin:not(.saml).no-right-panel {
   width: 522px;
 }
 
 #gaia-signin.saml {
   padding: 75px 0 0;
 }
 
 #signin-right {
-  -webkit-margin-before: 80px;
   -webkit-margin-start: 30px;
+  margin-top: 80px;
   top: 60px;
   width: 200px;
 }
 
 #signin-right,
 #enterprise-info-container,
 #saml-info-container {
   font-size: 12px;
 }
 
@@ skipping 119 matching lines @@
   left: 0;
   position: absolute;
   right: 0;
   text-align: center;
   top: 50px;
 }
 
 #saml-notice-message {
   margin: 0 auto;
 }