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

chrome/browser/resources/user_manager/user_manager_tutorial.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.
  */
 
 .tutorial-slide {
   -webkit-transition: opacity 200ms ease-in-out;
   background-color: white;
   border-radius: 2px;
   bottom: 0;
   box-shadow: 0 2px 5px rgba(0, 0, 0, 0.25);
   height: 408px;
   left: 0;
   margin: auto;
   position: absolute;
   right: 0;
   top: 0;
   width: 320px;
   z-index: 100;
 }
 
+.tutorial-slide.single-pod {
+  margin-left: 30px;
+}
+
+html[dir=rtl] .tutorial-slide.single-pod {
+  margin-right: 30px;
+}
+
 .hidden {
   opacity: 0;
   pointer-events: none;
 }
 
 #slide-guests {
   bottom: 20px;
   left: 20px;
   margin: 0;
   top: auto;
@@ skipping 130 matching lines @@
   background-color: rgb(179, 229, 252);
   background-image: url(
       'chrome://theme/IDR_ICON_USER_MANAGER_TUTORIAL_FRIENDS');
 }
 
 #slide-complete .slide-image {
   background-color: white;
   background-image: url(
       'chrome://theme/IDR_ICON_USER_MANAGER_TUTORIAL_COMPLETE');
 }