Accessibility: the Thickbox "Close" control should always be a button.

Fix the last case where the "Close" control was still a link. All the other ones
were already changed in buttons.

Fixes #36267.
Built from https://develop.svn.wordpress.org/trunk@37531


git-svn-id: http://core.svn.wordpress.org/trunk@37499 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/thickbox/thickbox.css

@@ -145,3 +145,12 @@
 #TB_closeWindowButton:focus .tb-close-icon {
 	color: #00a0d2;
 }
+
+#TB_closeWindowButton:focus .tb-close-icon {
+	-webkit-box-shadow:
+		0 0 0 1px #5b9dd9,
+		0 0 2px 1px rgba(30, 140, 190, .8);
+	box-shadow:
+		0 0 0 1px #5b9dd9,
+		0 0 2px 1px rgba(30, 140, 190, .8);
+}

wp-includes/js/thickbox/thickbox.js

@@ -212,7 +212,7 @@ function tb_show(caption, url, imageGroup) {//function called when the user clic
 			}else{// not an iframe, ajax
 					if(jQuery("#TB_window").css("visibility") != "visible"){
 						if(params['modal'] != "true"){//ajax no modal
-						jQuery("#TB_window").append("<div id='TB_title'><div id='TB_ajaxWindowTitle'>"+caption+"</div><div id='TB_closeAjaxWindow'><a href='#' id='TB_closeWindowButton'><div class='tb-close-icon'></div></a></div></div><div id='TB_ajaxContent' style='width:"+ajaxContentW+"px;height:"+ajaxContentH+"px'></div>");
+						jQuery("#TB_window").append("<div id='TB_title'><div id='TB_ajaxWindowTitle'>"+caption+"</div><div id='TB_closeAjaxWindow'><button type='button' id='TB_closeWindowButton'><span class='screen-reader-text'>"+thickboxL10n.close+"</span><span class='tb-close-icon'></span></button></div></div><div id='TB_ajaxContent' style='width:"+ajaxContentW+"px;height:"+ajaxContentH+"px'></div>");
 						}else{//ajax modal
 						jQuery("#TB_overlay").unbind();
 						jQuery("#TB_window").append("<div id='TB_ajaxContent' class='TB_modal' style='width:"+ajaxContentW+"px;height:"+ajaxContentH+"px;'></div>");

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37530';
+$wp_version = '4.6-alpha-37531';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.