[ChromeOS] Add an extra stage to remove a user in WebUI login.

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

 /* Copyright (c) 2011 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 user pods row of account picker UI.
  */
 
 podrow {
   -webkit-box-align: center;
   -webkit-box-pack: center;
@@ skipping 117 matching lines @@
   top: 193px;
   visibility: hidden;
 }
 
 .pod.focused .enter-guest-button {
   opacity: 1;
   visibility: visible;
 }
 
 .remove-user-button {
+  -webkit-transition: width .1s ease-in-out, background .2s ease-in-out;
   -webkit-box-shadow: none;
   background: url('chrome://theme/IDR_CLOSE_BAR') center center no-repeat;
   border: 0;
   height: 16px;
   margin: 0;
   min-width: 16px;
   padding: 0;
   position: absolute;
   right: 14px;
   top: 14px;
   width: 16px;
 }
 
 .remove-user-button:hover {
   -webkit-box-shadow: none;
   background: url('chrome://theme/IDR_CLOSE_BAR_H') center center no-repeat;
 }
+
+.remove-user-button.active {
+  background-color: #e94949;
+  background-image: none;
+  border-radius: 4px;
+  color: white;
+  font-size: 10px;
+  height: initial;
+  padding: 2px 4px;
+  width: initial;
+}