[Mac, Win] Show a user manager tutorial once per profile.

chrome/browser/resources/login/screen_container.css

 /* Copyright 2014 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.
  */
 
 #outer-container {
   -webkit-box-align: center;
   -webkit-box-pack: center;
   -webkit-perspective: 600px;
   bottom: 51px;  /* Leave space for the header bar */
   display: -webkit-box;
   left: 0;
   position: absolute;
   right: 0;
   top: 0;
 }
 
 #inner-container {
   border-radius: 2px;
   padding: 0;
   position: relative;
 }
 
 #inner-container.animation {
   overflow: hidden;
 }
 
+#inner-container.disabled {
+  opacity: 0.4;
+  pointer-events: none;
+}
+
 /* Screens that have a border and background. */
 #oobe.autolaunch #inner-container,
 #oobe.connect #inner-container,
 #oobe.enrollment #inner-container,
 #oobe.eula #inner-container,
 #oobe.gaia-signin #inner-container,
 #oobe.kiosk-enable #inner-container,
 #oobe.oauth-enrollment #inner-container,
 #oobe.reset #inner-container,
 #oobe.update #inner-container,
@@ skipping 129 matching lines @@
   line-height: 31px;
   text-transform: lowercase;
   width: 23em;
 }
 
 .header-section::before {
   /* Divider in header between product name and title,
    * like "[Product name] > [step header]". */
   content: '\00A0\203A\00A0\00A0';
 }
-