Slightly modified ETA computation algorithm. Also modified UI of the

chrome/browser/resources/chromeos/login/oobe.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.
  *
  * This is the stylesheet used by the Out of the box experience (OOBE) flow,
  * sign in and lock screens.
  */
 
 html,
 body {
@@ skipping 906 matching lines @@
   -webkit-margin-start: 74px;
 }
 
 #update progress {
   -webkit-margin-after: 4px;
   -webkit-margin-before: 34px;
   height: 15px;
   width: 300px;
 }
 
-#update #update-estimated-time-left {
+#update .progress-message {
   -webkit-margin-before: 4px;
-}
-
-#update #update-estimated-time-left {
   color: #a3a3a3;
   font-size: 13px;
   text-align: center;
 }
 
 .eula-columns {
   display: -webkit-box;
   width: 630px;
 }
 
@@ skipping 382 matching lines @@
   width: 100%;
 }
 
 .background-initial {
   opacity: 0;
 }
 
 .background-final {
   opacity: 1;
 }