diff --git a/core/modules/system/lib/Drupal/system/Controller/SystemController.php b/core/modules/system/lib/Drupal/system/Controller/SystemController.php
new file mode 100644
index 0000000..7054e95
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Controller/SystemController.php
@@ -0,0 +1,40 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Controller\SystemController.
+ */
+
+namespace Drupal\system\Controller;
+
+use Drupal\Core\Controller\ControllerInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpFoundation\RedirectResponse;
+
+
+/**
+ * Returns responses for System routes.
+ */
+class SystemController implements ControllerInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static();
+  }
+
+  /**
+   * Sets whether the admin menu is in compact mode or not.
+   *
+   * @param string $mode
+   *   Valid values are 'on' and 'off'.
+   *
+   * @return \Symfony\Component\HttpFoundation\RedirectResponse
+   */
+  function compactPage($mode) {
+    user_cookie_save(array('admin_compact_mode' => ($mode == 'on')));
+    return new RedirectResponse(url('<front>', array('absolute' => TRUE)));
+  }
+
+}