diff --git a/core/lib/Drupal/Component/Utility/Xss.php b/core/lib/Drupal/Component/Utility/Xss.php
index be81948..75b90b5 100644
--- a/core/lib/Drupal/Component/Utility/Xss.php
+++ b/core/lib/Drupal/Component/Utility/Xss.php
@@ -85,9 +85,8 @@ public static function filter($string, $html_tags = array('a', 'em', 'strong', '
     // Named entities.
     $string = preg_replace('/&([A-Za-z][A-Za-z0-9]*;)/', '&\1', $string);
     $html_tags = array_flip($html_tags);
-    $class = get_called_class();
-    $splitter = function ($matches) use ($html_tags, $class, $mode) {
-      return $class::split($matches, $html_tags, $mode);
+    $splitter = function ($matches) use ($html_tags, $mode) {
+      return static::split($matches[1], $html_tags, $mode);
     };
     return preg_replace_callback('%
       (
@@ -125,13 +124,8 @@ public static function filterAdmin($string) {
   /**
    * Processes an HTML tag.
    *
-   * Call \Drupal\Component\Xss\filter() instead of this helper.
-   *
-   * @param array $matches
-   *   An array with various meaning depending on the value of $store.
-   *   If $store is TRUE then the array contains the allowed tags.
-   *   If $store is FALSE then the array has one element, the HTML tag to
-   *   process.
+   * @param string $string
+   *   The HTML tag to process.
    * @param array $html_tags
    *   An array where the keys are the allowed tags and the values are not
    *   used.
@@ -143,9 +137,7 @@ public static function filterAdmin($string) {
    *   If the element isn't allowed, an empty string. Otherwise, the cleaned up
    *   version of the HTML element.
    */
-  public static function split($matches, $html_tags, $split_mode = Xss::FILTER_MODE_WHITELIST) {
-    $string = $matches[1];
-
+  protected static function split($string, $html_tags, $split_mode) {
     if (substr($string, 0, 1) != '<') {
       // We matched a lone ">" character.
       return '&gt;';