Resolve #3436146 "Request subscriber"

Closes #3436146

core/lib/Drupal/Core/Cache/EventSubscriber/CacheTagPreloadSubscriber.php

+<?php
+
+namespace Drupal\Core\Cache\EventSubscriber;
+
+use Drupal\Core\Cache\CacheTagsChecksumInterface;
+use Drupal\Core\Cache\CacheTagsChecksumPreloadInterface;
+use Drupal\Core\Site\Settings;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\HttpKernel\Event\RequestEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+
+/**
+ * Preloads frequently used cache tags.
+ */
+class CacheTagPreloadSubscriber implements EventSubscriberInterface {
+
+  public function __construct(protected CacheTagsChecksumInterface $cacheTagsChecksum) {
+  }
+
+  /**
+   * Preloads frequently used cache tags.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\RequestEvent $event
+   *   The request event.
+   */
+  public function onRequest(RequestEvent $event): void {
+    if ($event->isMainRequest() && $this->cacheTagsChecksum instanceof CacheTagsChecksumPreloadInterface) {
+      $default_preload_cache_tags = array_merge([
+        'route_match',
+        'access_policies',
+        'routes',
+        'router',
+        'entity_types',
+        'entity_field_info',
+        'entity_bundles',
+        'local_task',
+        'library_info',
+        'user_values',
+      ], Settings::get('cache_preload_tags', []));
+      $this->cacheTagsChecksum->registerCacheTagsForPreload($default_preload_cache_tags);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents(): array {
+    $events[KernelEvents::REQUEST][] = ['onRequest', 500];
+    return $events;
+  }
+
+}