diff --git a/core/modules/field_ui/field_ui.admin.inc b/core/modules/field_ui/field_ui.admin.inc
index 3ee1eaa..29c2392 100644
--- a/core/modules/field_ui/field_ui.admin.inc
+++ b/core/modules/field_ui/field_ui.admin.inc
@@ -451,9 +451,13 @@ function field_ui_get_destinations($destinations) {
  * Returns the next redirect path in a multipage sequence.
  */
 function field_ui_next_destination($entity_type, $bundle) {
-  $destinations = !empty($_REQUEST['destinations']) ? $_REQUEST['destinations'] : array();
+  $request_destination = \Drupal::request()->get('destinations');
+  $destinations = !empty($request_destination) ? $request_destination : array();
   if (!empty($destinations)) {
-    unset($_REQUEST['destinations']);
+    // This is closest to unset() I could think of.
+    // unset($_REQUEST['destinations']);
+    \Drupal::request()->query->remove('destinations');
+    \Drupal::request()->request->remove('destinations');
     return field_ui_get_destinations($destinations);
   }
   $admin_path = Drupal::entityManager()->getAdminPath($entity_type, $bundle);
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/FieldOverview.php b/core/modules/field_ui/lib/Drupal/field_ui/FieldOverview.php
index 44e4be7..18827df 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/FieldOverview.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/FieldOverview.php
@@ -644,7 +644,7 @@ public function submitForm(array &$form, array &$form_state) {
     if ($destinations) {
       $destination = drupal_get_destination();
       $destinations[] = $destination['destination'];
-      unset($_GET['destination']);
+      \Drupal::request()->query->remove('destination');
       $form_state['redirect'] = field_ui_get_destinations($destinations);
     }
     else {
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php
index d8788a7..fb09d5e 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php
@@ -248,9 +248,10 @@ public function submitForm(array &$form, array &$form_state) {
    */
   public function delete(array &$form, array &$form_state) {
     $destination = array();
-    if (isset($_GET['destination'])) {
+    $query_destination = \Drupal::request()->query->get('destination');
+    if (isset($query_destination)) {
       $destination = drupal_get_destination();
-      unset($_GET['destination']);
+      \Drupal::request()->query->remove('destination');
     }
     $form_state['redirect'] = array('admin/structure/types/manage/' . $this->instance['bundle'] . '/fields/' . $this->instance->id() . '/delete', array('query' => $destination));
   }
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index ce1b39b..cbf9f44 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -1243,7 +1243,6 @@ function system_library_info() {
       array('system', 'jquery'),
       array('system', 'drupal'),
       array('system', 'drupalSettings'),
-      array('system', 'drupal.ajax'),
       array('system', 'drupal.progress'),
       array('system', 'jquery.once'),
     ),