Makes the network dropdown keyboard accessible (focus friendly).

chrome/browser/resources/chromeos/login/oobe.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 the Out of the box experience (OOBE) flow.
  */
 
 body {
   background: -webkit-gradient(radial, center center, 0, center center, 400,
               from(#fefefe), to(#efefef));
@@ skipping 139 matching lines @@
 
 .progdot-active {
   opacity: 0.5;
 }
 
 .control-with-label {
   margin: 10px 0 10px 0;
   display: -webkit-box;
 }
 
-.label {
-  margin: 5px 5px 5px 0;
-  padding: 5px 5px 5px 0;
-  width: 170px;
-}
-
 .menu-area {
   margin: 5px 5px 5px 5px;
 }
 
 .menu-control {
   width: 250px;
 }
 
+.label {
+  margin: 5px 5px 5px 0;
+  padding: 5px 5px 5px 0;
+  width: 170px;
+}
+
 #connect {
   box-sizing: border-box;
   padding: 60px 0 0 145px;
 }
 
 #logging {
   clear: both;
   font-size: small;
   margin-top: 20px;
 }
@@ skipping 361 matching lines @@
   height: 24px;
   margin: 0;
   overflow: hidden;
   padding-top: 2px;
   padding-bottom: 2px;
   text-overflow: ellipsis;
   text-align: left;  
   text-indent: 4px;
   white-space: nowrap;
   width: 250px;
+  z-index: 10;
 }
 
 .dropdown-title:hover {
   -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
   background-image: url('../../shared/images/select.png'),
                     -webkit-linear-gradient(#fefefe, #f8f8f8 40%, #e9e9e9);
   color: #333;  
   background-position: center right;
   background-repeat: no-repeat;
 }
 
 .dropdown-title:active {
   -webkit-box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.2);
   background-image: url('../../shared/images/select.png'),
                     -webkit-linear-gradient(#f4f4f4, #efefef 40%, #dcdcdc);
   color: #444;
 }
 
 .dropdown-container {
   background: #f7f7f7;
   border: 1px solid #7c91bf;
   padding-bottom: 2px;
   padding-top: 2px;
   position: relative;
   top: 100%;
   width: 248px;
-  z-index: 1;
+  z-index: 10;
 }
 
 .dropdown-item-container {
   display: -webkit-box;
   height: 24px;
   padding-left: 5px;
 }
 
-.dropdown-item-container:hover {
+.dropdown-item-container.hover {
   background: #dce4fa;
 }
 
 .dropdown-image {
   width: 24px;
 }
 
 .dropdown-item {
   cursor: default;
   color: #555;
@@ skipping 39 matching lines @@
 #version-labels {
   -webkit-transition: all .5s linear;
   bottom: 10px;
   color: #999;
   font-size: 11px;
   left: 10px;
   opacity: 1.0;
   position: absolute;
   text-shadow: 0 1px 1px #fff;
 }
+
+.dropdown-overlay {
+  position: fixed;
+  top: 0;
+  bottom: 0;
+  right: 0;
+  left: 0;
+  z-index: 5;
+}