ChromeOS GAIA: Fixed size for close and back buttons on signin and enrollment screens

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

 /* Copyright 2015 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.
  */
 
 #oauth-enrollment {
   height: 609px;
   padding: 0;
   width: 522px;
 }
@@ skipping 119 matching lines @@
   display: none;
 }
 
 #oauth-saml-notice-message {
   color: rgb(106, 106, 106);
   font-size: 13px;
   margin: 0 auto;
 }
 
 #oauth-enroll-cancel-button {
-  background: transparent none;
   background-image: url(chrome://theme/IDR_LOGIN_CLOSE_BUTTTON);
-  background-position: center;
-  background-repeat: no-repeat;
-  height: 14px;
-  position: absolute;
-  right: 15px;
-  top: 15px;
-  width: 14px;
-  z-index: 1;
+  right: 0;
 }
 
 html[dir=rtl] #oauth-enroll-cancel-button {
-  left: 15px;
+  left: 0;
   right: auto;
 }
 
 #oauth-enrollment.saml #oauth-enroll-cancel-button {
   background-image: url(chrome://theme/IDR_LOGIN_CLOSE_BUTTTON_ON_WHITE);
 }
 
 #oauth-enroll-cancel-button:hover {
   cursor: pointer;
 }
 
 #oauth-enroll-back-button {
-  background: transparent none;
   background-image: url(chrome://theme/IDR_LOGIN_BACK_BUTTTON);
-  background-position: center;
-  background-repeat: no-repeat;
-  height: 18px;
-  left: 14px;
-  position: absolute;
-  top: 14px;
-  width: 18px;
-  z-index: 1;
+  left: 0;
 }
 
 html[dir=rtl] #oauth-enroll-back-button {
   -webkit-transform: scaleX(-1);
   left: auto;
-  right: 14px;
+  right: 0;
 }
 
 #oauth-enrollment.saml #oauth-enroll-back-button {
   display: none;
 }
 
 #oauth-enroll-back-button:hover {
   cursor: pointer;
 }
 
 .oauth-enroll-textbox {
   display: inline-block;
   position: relative;
   top: 10px;
   vertical-align: top;
 }
 
 .oauth-enroll-textbox.oauth-enroll-attribute-field[type='text'] {
   border-color: black;
   font-size: 16px;
   position: relative;
   width: 250px;
 }
 
 .oauth-enroll-textbox.auth-enroll-attribute-label {
   display: inline;
   position: relative;
 }