Remove the no longer used Headerless_Upgrader_Skin class, it's been replaced by Language_Pack_Upgrader_Skin.

See #18200, [25806]

Built from https://develop.svn.wordpress.org/trunk@25807


git-svn-id: http://core.svn.wordpress.org/trunk@25719 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/class-wp-upgrader-skins.php

@@ -661,17 +661,3 @@ class Automatic_Upgrader_Skin extends WP_Upgrader_Skin {
 	function before() {}
 	function after() {}
 }
-
-/**
- * A basic Upgrader skin which doesn't have any headers or footers.
- *
- * @package WordPress
- * @subpackage Upgrader
- * @since 3.7.0
- */
-class Headerless_Upgrader_Skin extends WP_Upgrader_Skin {
-	function before() {}
-	function after() {}
-	function header() {}
-	function footer() {}
-}