Issue #1843844 by Crell: Convert cron to new routing system.

core/modules/system/lib/Drupal/system/CronController.php

+<?php
+
+/**
+ * @file
+ * Definition of Drupal\system\CronController.
+ */
+
+namespace Drupal\system;
+
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+
+/**
+ * Controllers for Cron handling.
+ */
+class CronController {
+
+  /**
+   * Run Cron once.
+   *
+   * @return Symfony\Component\HttpFoundation\Response
+   *   A Symfony response object.
+   */
+  public function run($key) {
+    if (!$this->access($key)) {
+      throw new AccessDeniedHttpException();
+    }
+
+    // @todo Make this an injected object.
+    drupal_cron_run();
+
+    // HTTP 204 is "No content", meaning "I did what you asked and we're done."
+    return new Response('', 204);
+  }
+
+  /**
+   * Determines if the user has access to run cron.
+   *
+   * @todo Eliminate this method in favor of a new-style access checker once
+   * http://drupal.org/node/1793520 gets in.
+   */
+  function access($key) {
+    if ($key != state()->get('system.cron_key')) {
+      watchdog('cron', 'Cron could not run because an invalid key was used.', array(), WATCHDOG_NOTICE);
+      return FALSE;
+    }
+    elseif (config('system.maintenance')->get('enabled')) {
+      watchdog('cron', 'Cron could not run because the site is in maintenance mode.', array(), WATCHDOG_NOTICE);
+      return FALSE;
+    }
+
+    return TRUE;
+  }
+
+}

core/modules/system/system.module

@@ -564,13 +564,6 @@ function system_element_info() {
  * Implements hook_menu().
  */
 function system_menu() {
-  $items['cron/%'] = array(
-    'title' => 'Run cron',
-    'page callback' => 'system_cron_page',
-    'access callback' => 'system_cron_access',
-    'access arguments' => array(1),
-    'type' => MENU_CALLBACK,
-  );
   $items['system/files'] = array(
     'title' => 'File download',
     'page callback' => 'file_download',
@@ -1076,41 +1069,6 @@ function system_menu() {
   return $items;
 }
 
-/**
- * Page callback; Execute cron tasks.
- *
- * @see system_cron_access().
- */
-
-function system_cron_page() {
-  drupal_page_is_cacheable(FALSE);
-  drupal_cron_run();
-
-  // HTTP 204 is "No content", meaning "I did what you asked and we're done."
-  return new Response('', 204);
-}
-
-/**
- * Access callback for system_cron().
- *
- * @param string $key
- *   A hash to validate the page request origin.
- *
- * @see system_cron_page().
- */
-function system_cron_access($key) {
-  if ($key != state()->get('system.cron_key')) {
-    watchdog('cron', 'Cron could not run because an invalid key was used.', array(), WATCHDOG_NOTICE);
-    return FALSE;
-  }
-  elseif (config('system.maintenance')->get('enabled')) {
-    watchdog('cron', 'Cron could not run because the site is in maintenance mode.', array(), WATCHDOG_NOTICE);
-    return FALSE;
-  }
-
-  return TRUE;
-}
-
 /**
  * Theme callback for the default batch page.
  */

core/modules/system/system.routing.yml

+cron:
+  pattern: '/cron/{key}'
+  defaults:
+    _controller: '\Drupal\system\CronController::run'