Signin screen polish in response to UI review

chrome/browser/resources/chromeos/login/md_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;
   bottom: 0;
   left: 0;
   min-height: 34px;  /* Should be consistent with .header-bar-item's height. */
   padding-bottom: 6px;
@@ skipping 42 matching lines @@
 #login-header-bar button:not(.button-restricted),
 #login-header-bar button:active:not(.button-restricted),
 #login-header-bar button:focus:not(.button-restricted),
 #login-header-bar button:hover:not(.button-restricted) {
   color: white !important;
   opacity: 1 !important;
 }
 
 .header-bar-item {
   height: 34px;
+  z-index: 3; /* Stays above the scrollable container. */
 }
 
 .add-supervised-user-menu {
   display: none;
 }
 
 #more-settings-header-bar-item.active button.add-supervised-user-menu {
   background-color: white;
   border: 1px solid lightgray;
   border-radius: 2px;
   bottom: 0;
   color: black !important;
   display: block;
   font-size: 13px;
   height: auto;
   min-height: 34px;
   padding: 0 16px;
   position: absolute;
   text-align: center;
   white-space: nowrap;
   z-index: 3;
 }
 
 #more-settings-header-bar-item.active button.add-supervised-user-menu:focus {
-  border: 2px solid var(--google-blue-500);
-  border-radius: 2px;
-  padding: 0 15px;
+  font-weight: bold;
 }
 
 html[dir=rtl] .header-bar-item {
   background-position: right center;
 }
 
 #login-header-bar #shutdown-button-text,
 #login-header-bar #restart-button-text,
+#login-header-bar #show-apps-button-text,
 #login-header-bar #add-user-button-text,
 #login-header-bar #guest-user-button-text,
 #login-header-bar #more-settings-button-text,
 #login-header-bar #cancel-multiple-sign-in-button-text,
 #login-header-bar #sign-out-user-button-text,
 #login-header-bar #unlock-user-button-text {
   -webkit-padding-start: 28px;
   background-position: left center;
   background-repeat: no-repeat;
   background-size: 20px;
 }
 
 html[dir=rtl] #login-header-bar #shutdown-button-text,
 html[dir=rtl] #login-header-bar #restart-button-text,
+html[dir=rtl] #login-header-bar #show-apps-button-text,
 html[dir=rtl] #login-header-bar #add-user-button-text,
 html[dir=rtl] #login-header-bar #more-settings-button-text,
 html[dir=rtl] #login-header-bar #guest-user-button-text,
 html[dir=rtl] #login-header-bar #cancel-multiple-sign-in-button-text,
 html[dir=rtl] #login-header-bar #sign-out-user-button-text,
 html[dir=rtl] #login-header-bar #unlock-user-button-text {
   background-position: right center;
 }
 
 #login-header-bar #shutdown-button,
@@ skipping 12 matching lines @@
   position: relative;
 }
 
 #login-header-bar #shutdown-button-text,
 #login-header-bar #restart-button-text {
   background-image: -webkit-image-set(
       url(images/1x/shutdown.svg) 1x,
       url(images/2x/shutdown.svg) 2x );
 }
 
+#login-header-bar #show-apps-button-text {
+  background-image: -webkit-image-set(
+      url(images/1x/show-apps.svg) 1x,
+      url(images/2x/show-apps.svg) 2x );
+}
+
 #login-header-bar #add-user-button-text {
   background-image: -webkit-image-set(
       url(images/1x/add-person.svg) 1x,
       url(images/2x/add-person.svg) 2x );
 }
 
 #login-header-bar #more-settings-button-text {
   background-image: -webkit-image-set(
       url(images/1x/more-settings.svg) 1x,
       url(images/2x/more-settings.svg) 2x );
@@ skipping 21 matching lines @@
   background-image: -webkit-image-set(
       url(images/1x/unlock.svg) 1x,
       url(images/2x/unlock.svg) 2x );
 }
 
 .button-restricted {
   border: 1px solid transparent;
   color: white !important;
   opacity: 0.4 !important;
 }