Issue #2421681 by JeroenT, develCuy, developermitesh: Remove drupal_pre_render_html

core/includes/theme.inc

@@ -1269,15 +1269,6 @@ function _template_preprocess_default_variables() {
   return $variables;
 }
 
-/**
- * #pre_render callback for the html element type.
- *
- * @deprecated Use \Drupal\Core\Render\Element\Html::preRenderHtml().
- */
-function drupal_pre_render_html(array $element) {
-  return Element\Html::preRenderHtml($element);
-}
-
 /**
  * Prepares variables for HTML document templates.
  *