only in patch2:
unchanged:
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -668,8 +668,6 @@ function _url($path = NULL, array $options = array()) {
  * @return
  *   A ; separated string ready for insertion in a HTTP header. No escaping is
  *   performed for HTML entities, so this string is not safe to be printed.
- *
- * @see drupal_add_http_header()
  */
 function drupal_http_header_attributes(array $attributes = array()) {
   foreach ($attributes as $attribute => &$data) {
only in patch2:
unchanged:
--- a/core/modules/system/tests/modules/system_test/system_test.module
+++ b/core/modules/system/tests/modules/system_test/system_test.module
@@ -2,6 +2,7 @@
 
 use Drupal\Core\Extension\Extension;
 use Symfony\Component\HttpFoundation\RedirectResponse;
+use Symfony\Component\HttpFoundation\Response;
 
 /**
  * Sets a header.
@@ -10,7 +11,8 @@
  */
 function system_test_set_header() {
   $query = \Drupal::request()->query->all();
-  drupal_add_http_header($query['name'], $query['value']);
+  $response = new Response();
+  $response->headers->set($query['name'], $query['value']);
   return t('The following header was set: %name: %value', array('%name' => $query['name'], '%value' => $query['value']));
 }