Jetpack_Custom_CSS_Enhancements::preview_skip_stylesheet PHP Method

    public static function preview_skip_stylesheet($skip_value)
    {
        global $wp_customize;
        if (!is_customize_preview()) {
            return $skip_value;
        }
        $setting = $wp_customize->get_setting('jetpack_custom_css[replace]');
        if (!$setting) {
            return $skip_value;
        }
        $customized_replace = $setting->post_value();
        if (null !== $customized_replace) {
            return $customized_replace;
        }
        return $skip_value;
    }