Made "more" menu on login screen flexible.

chrome/browser/resources/chromeos/login/header_bar.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.
  */
 
 #login-header-bar {
   -webkit-padding-start: 15px;
   border-bottom: 3px solid black;
   bottom: 0;
   left: 0;
@@ skipping 59 matching lines @@
 }
 
 #more-settings-header-bar-item.active button.add-supervised-user-menu {
   background-color: white;
   border: 1px solid lightgray;
   border-radius: 2px;
   bottom: 15px;
   color: black !important;
   display: block;
   font-size: 13px;
+  height: auto;
   left: 15px;
   margin: 0 0 -10px -10px;
+  min-height: 34px;
   position: absolute;
   text-align: center;
   width: 180px;
 }
 
 html[dir=rtl] .header-bar-item {
   background-position: right center;
 }
 
 #login-header-bar #shutdown-button,
@@ skipping 44 matching lines @@
 #login-header-bar #cancel-multiple-sign-in-button {
   /* TODO(dzhioev): replace with appropriate image when possible. */
   background-image: url(chrome://theme/IDR_PANEL_CLOSE);
 }
 
 .button-restricted {
   border: 1px solid transparent;
   color: white !important;
   opacity: 0.4 !important;
 }