Fatal error: Uncaught Error: Class "Drupal\Core\Entity\EntityConfirmFormBase" not found in /home/www/drupal8/test/core/modules/image/src/Form/ImageStyleFlushForm.php:13 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/image/src/Form/ImageStyleFlushForm.php on line 13