diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 319fb2f..96eb451 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2440,32 +2440,28 @@ function theme_feed_icon($variables) {
  *
  * @param array $variables
  *   An associative array containing:
- *   - element: An associative array describing the tag:
- *     - #tag: The tag name to output. Typical tags added to the HTML HEAD:
- *       - meta: Used to provide meta information, such as a page refresh.
- *       - link: Used to refer to stylesheets and other contextual information.
- *       - script: Used for loading JavaScript.
- *     - #attributes: (optional) An array of HTML attributes to apply to the
- *       tag.
- *     - #value: (optional) A string containing tag content, such as inline CSS.
- *     - #value_prefix: (optional) A string to prepend to #value, e.g. a CDATA
- *       wrapper prefix.
- *     - #value_suffix: (optional) A string to append to #value, e.g. a CDATA
- *       wrapper suffix.
+ *   - tag: The tag name to output. Typical tags added to the HTML HEAD:
+ *     - meta: Used to provide meta information, such as a page refresh.
+ *     - link: Used to refer to stylesheets and other contextual information.
+ *     - script: Used for loading JavaScript.
+ *   - attributes: (optional) An array of HTML attributes to apply to the
+ *     tag.
+ *   - value: (optional) A string containing tag content, such as inline CSS.
+ *   - value_prefix: (optional) A string to prepend to #value, e.g. a CDATA
+ *     wrapper prefix.
+ *   - value_suffix: (optional) A string to append to #value, e.g. a CDATA
+ *     wrapper suffix.
  */
 function template_preprocess_html_tag(&$variables) {
-  $element = $variables['element'];
-  $variables['attributes'] = isset($element['#attributes']) ? new Attribute($element['#attributes']) : new Attribute(array());
-  $variables['tag'] = $element['#tag'];
-  if (isset($element['#value'])) {
-    $variables['value'] = $element['#value'];
-  }
-  if (isset($element['#value_prefix'])) {
-    $variables['value_prefix'] = $element['#value_prefix'];
-  }
-  if (isset($element['#value_prefix'])) {
-    $variables['value_suffix'] = $element['#value_suffix'];
+  // Remove default 'html-tag' class from attributes, but leave other classes.
+  // @todo: Remove this hack once http://drupal.org/node/1938430 lands.
+  if (!empty($variables['attributes']['class'])) {
+    $variables['attributes']['class'] = array_diff($variables['attributes']['class'], array('html-tag'));
+    if (empty($variables['attributes']['class'])) {
+      unset($variables['attributes']['class']);
+    }
   }
+  $variables['attributes'] = new Attribute($variables['attributes']);
 }
 
 /**
@@ -3204,7 +3200,7 @@ function drupal_common_theme() {
       'variables' => array('size' => 1),
     ),
     'html_tag' => array(
-      'render element' => 'element',
+      'variables' => array('tag' => NULL, 'value' => NULL, 'attributes' => array(), 'value_prefix' => NULL, 'value_suffix' => NULL),
       'template' => 'html-tag',
     ),
     // From theme.maintenance.inc.
diff --git a/core/modules/system/templates/html-tag.html.twig b/core/modules/system/templates/html-tag.html.twig
index a917cc3..83a876c 100644
--- a/core/modules/system/templates/html-tag.html.twig
+++ b/core/modules/system/templates/html-tag.html.twig
@@ -22,10 +22,10 @@
  @todo Delete this file once http://drupal.org/node/1825090 is resolved.
 #}
 {#
-  We use 'is defined' here because <script> always needs a closing tag, and
+  We use 'is not null' here because <script> always needs a closing tag, and
   'value' is set to an empty string for <script> tags with only a src value.
 #}
-{% if value is defined -%}
+{% if value is not null -%}
   <{{ tag }}{{ attributes }}>
     {%- if value_prefix -%}
       {{- value_prefix -}}