Index: src/wp-includes/admin-bar.php
===================================================================
--- src/wp-includes/admin-bar.php	(revision 26869)
+++ src/wp-includes/admin-bar.php	(working copy)
@@ -714,20 +714,29 @@
 	if ( is_admin() )
 		return;
 
+	$focus    = 'document.getElementById(\'wp-admin-bar-search\').className += \' focus\';';
+	$focusout = 'document.getElementById(\'wp-admin-bar-search\').className = document.getElementById(\'wp-admin-bar-search\').className.replace(/\bfocus\b/,\'\').trim();';
+
 	$form  = '<form action="' . esc_url( home_url( '/' ) ) . '" method="get" id="adminbarsearch">';
-	$form .= '<input class="adminbar-input" name="s" id="adminbar-search" type="text" value="" maxlength="150" />';
+	$form .= '<input class="adminbar-input" name="s" id="adminbar-search" type="text" value="" maxlength="150" placeholder="' . __('Search') . '" onfocus="' . $focus . '" onfocusout="' . $focusout . '" />';
 	$form .= '<input type="submit" class="adminbar-button" value="' . __('Search') . '"/>';
 	$form .= '</form>';
 
 	$wp_admin_bar->add_menu( array(
 		'parent' => 'top-secondary',
 		'id'     => 'search',
-		'title'  => $form,
+		'title'  => '<span class="screen-reader-text">' . __( 'Search' ) . '</span>',
 		'meta'   => array(
 			'class'    => 'admin-bar-search',
 			'tabindex' => -1,
 		)
 	) );
+
+	$wp_admin_bar->add_menu( array(
+		'parent' => 'search',
+		'id'     => 'adminbarsearch',
+		'title'  => $form
+	) );
 }
 
 /**
Index: src/wp-includes/css/admin-bar.css
===================================================================
--- src/wp-includes/css/admin-bar.css	(revision 26869)
+++ src/wp-includes/css/admin-bar.css	(working copy)
@@ -101,7 +101,7 @@
 }
 
 /* Prevent a Chrome bug that inadvertantly activates
-   :hover states on an element that touches the extreme 
+   :hover states on an element that touches the extreme
    top left corner of the viewport. See #18868 */
 #wpadminbar .quicklinks {
 	border-left: 1px solid transparent;
@@ -182,6 +182,7 @@
 #wpadminbar .quicklinks .menupop ul li .ab-item,
 #wpadminbar .quicklinks .menupop ul li a strong,
 #wpadminbar .quicklinks .menupop.hover ul li .ab-item,
+#wpadminbar .quicklinks .menupop.focus ul li .ab-item,
 #wpadminbar.nojs .quicklinks .menupop:hover ul li .ab-item,
 #wpadminbar .shortlink-input {
 	line-height: 26px;
@@ -195,18 +196,21 @@
 }
 
 #wpadminbar.nojs li:hover > .ab-sub-wrapper,
-#wpadminbar li.hover > .ab-sub-wrapper {
+#wpadminbar li.hover > .ab-sub-wrapper,
+#wpadminbar li.focus > .ab-sub-wrapper {
 	display: block;
 }
 
 #wpadminbar .menupop li:hover > .ab-sub-wrapper,
-#wpadminbar .menupop li.hover > .ab-sub-wrapper {
+#wpadminbar .menupop li.hover > .ab-sub-wrapper,
+#wpadminbar .menupop li.focus > .ab-sub-wrapper {
 	margin-left: 100%;
 	margin-top: -32px;
 }
 
 #wpadminbar .ab-top-secondary .menupop li:hover > .ab-sub-wrapper,
-#wpadminbar .ab-top-secondary .menupop li.hover > .ab-sub-wrapper {
+#wpadminbar .ab-top-secondary .menupop li.hover > .ab-sub-wrapper,
+#wpadminbar .ab-top-secondary .menupop li.focus > .ab-sub-wrapper {
 	margin-left: 0;
 	left: inherit;
 	right: 100%;
@@ -215,13 +219,15 @@
 #wpadminbar .ab-top-menu > li > .ab-item:focus,
 #wpadminbar.nojq .quicklinks .ab-top-menu > li > .ab-item:focus,
 #wpadminbar .ab-top-menu > li:hover > .ab-item,
-#wpadminbar .ab-top-menu > li.hover > .ab-item {
+#wpadminbar .ab-top-menu > li.hover > .ab-item,
+#wpadminbar .ab-top-menu > li.focus > .ab-item {
 	background: #333;
 	color: #2ea2cc;
 }
 
 #wpadminbar > #wp-toolbar li:hover span.ab-label,
 #wpadminbar > #wp-toolbar li.hover span.ab-label,
+#wpadminbar > #wp-toolbar li.focus span.ab-label,
 #wpadminbar > #wp-toolbar a:focus span.ab-label {
 	color: #2ea2cc;
 }
@@ -285,6 +291,7 @@
 #wpadminbar li .ab-item:focus:before,
 #wpadminbar li.hover .ab-icon:before,
 #wpadminbar li.hover .ab-item:before,
+#wpadminbar li.focus .ab-item:before,
 #wpadminbar li:hover #adminbarsearch:before {
 	color: #2ea2cc;
 }
@@ -551,99 +558,29 @@
 /**
  * Search
  */
-#wpadminbar #wp-admin-bar-search .ab-item {
-	padding: 0;
-	background: transparent;
+#wpadminbar #wp-admin-bar-search > .ab-item {
+	padding: 0 5px;
 }
 
-#wpadminbar #adminbarsearch {
-	position: relative;
-	height: 32px;
-	padding: 0 2px;
-}
-
-#wpadminbar #adminbarsearch:before {
-	position: absolute;
-	top: 6px;
-	left: 5px;
-	z-index: 20;
-	font: normal 20px/1 'dashicons' !important;
+#wpadminbar #wp-admin-bar-search > .ab-item:before {
 	content: '\f179';
-	speak: none;
-	-webkit-font-smoothing: antialiased;
-	-moz-osx-font-smoothing: grayscale;
+	font-size: 24px;
+	margin-right: 0;
 }
 
-#wpadminbar > #wp-toolbar > #wp-admin-bar-top-secondary > #wp-admin-bar-search #adminbarsearch input.adminbar-input {
-	position: relative;
-	z-index: 30;
-	font: 13px/24px "Open Sans", sans-serif;
-	height: 24px;
-	width: 24px;
-	padding: 0 3px 0 24px;
-	margin: 0;
-	color: #ccc;
-	background-color: rgba( 255, 255, 255, 0 );
-	border: none;
-	outline: none;
-	cursor: pointer;
-
-	-webkit-box-shadow: none;
-	box-shadow: none;
-
-	-moz-box-sizing: border-box;
-	-webkit-box-sizing: border-box;
-	-ms-box-sizing: border-box;
-	box-sizing: border-box;
-
-	-webkit-transition-duration: 400ms;
-	-webkit-transition-property: width, background;
-	-webkit-transition-timing-function: ease;
-	-moz-transition-duration: 400ms;
-	-moz-transition-property: width, background;
-	-moz-transition-timing-function: ease;
-	-o-transition-duration: 400ms;
-	-o-transition-property: width, background;
-	-o-transition-timing-function: ease;
+#wpadminbar #wp-admin-bar-search .ab-submenu {
+	padding-bottom: 10px;
 }
 
-#wpadminbar > #wp-toolbar > #wp-admin-bar-top-secondary > #wp-admin-bar-search #adminbarsearch input.adminbar-input:focus {
-	z-index: 10;
-	color: #000;
-	width: 200px;
-	background-color: rgba( 255, 255, 255, 0.9 );
-	cursor: text;
+#wpadminbar #wp-admin-bar-search .adminbar-input {
+	height: 14px;
+	padding: 4px;
 	border: 0;
+	line-height: normal;
+	font-size: 14px;
 }
 
-#wpadminbar.ie7 > #wp-toolbar > #wp-admin-bar-top-secondary > #wp-admin-bar-search #adminbarsearch input.adminbar-input {
-	margin-top: 3px;
-	width: 120px;
-}
-
-#wpadminbar.ie8 > #wp-toolbar > #wp-admin-bar-top-secondary > #wp-admin-bar-search #adminbarsearch input.adminbar-input {
-	margin-top: 4px;
-	background-color: #464646;
-}
-
-#wpadminbar.ie8 > #wp-toolbar > #wp-admin-bar-top-secondary > #wp-admin-bar-search #adminbarsearch input.adminbar-input:focus {
-	background-color: #fff;
-}
-
-#wpadminbar #adminbarsearch .adminbar-input::-webkit-input-placeholder {
-	color: #999;
-}
-#wpadminbar #adminbarsearch .adminbar-input:-moz-placeholder {
-	color: #999;
-}
-#wpadminbar #adminbarsearch .adminbar-input::-moz-placeholder {
-	color: #999;
-}
-#wpadminbar #adminbarsearch .adminbar-input:-ms-input-placeholder {
-	color: #999;
-}
-
-#wpadminbar #adminbarsearch .adminbar-button {
+#wpadminbar #wp-admin-bar-search .adminbar-button {
 	display: none;
 }
 
@@ -809,7 +746,8 @@
 	}
 
 	#wpadminbar .menupop li:hover > .ab-sub-wrapper,
-	#wpadminbar .menupop li.hover > .ab-sub-wrapper {
+	#wpadminbar .menupop li.hover > .ab-sub-wrapper,
+	#wpadminbar .menupop li.focus > .ab-sub-wrapper {
 		margin-top: -46px;
 	}
 
@@ -1002,6 +940,7 @@
 	/* Allow dropdown list items to appear normally */
 	#wpadminbar li:hover ul li,
 	#wpadminbar li.hover ul li,
+	#wpadminbar li.focus ul li,
 	#wpadminbar li:hover ul li:hover ul li {
 		display: list-item;
 	}