[cros] Button focus polishing on the login screen.

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 {
   height: 100%;
   width: 100%;
 }
 
 body {
   background: #fefefe;
   font-size: 14px;
   margin: 0;
   overflow: hidden;
   padding: 0;
 }
 
 button {
   font-family: inherit;
+  outline: none;
+}
+
+/* Follow same focus coloring as in widgets.css */
+button.custom-appearance:enabled {
+  -webkit-transition: border-color 200ms;
+  border: 1px solid transparent;
+}
+
+button.custom-appearance:enabled:focus {
+  border-color: rgb(77, 144, 254);
 }
 
 #outer-container {
   -webkit-box-align: center;
   -webkit-box-pack: center;
   bottom: 41px;  /* Leave space for the header bar */
   display: -webkit-box;
   left: 0;
   position: absolute;
   right: 0;
@@ skipping 723 matching lines @@
 }
 
 #notification-area a {
   color: rgb(37, 79, 155);
 }
 
 #notification-area .butter-bar {
   margin: 0 auto;
   max-width: 850px;
 }