See #53330. Built from https://develop.svn.wordpress.org/trunk@52215 git-svn-id: http://core.svn.wordpress.org/trunk@51807 1a063a9b-81f0-0310-95a4-ce76da25c4cd
WP_Customize_Setting::update()
WP_Customize_Custom_CSS_Setting::validate()
WP_Customize_Setting::sanitize()
$this
/