class ImageStyleStorage

class ImageStyleStorage extends ConfigEntityStorage implements ImageStyleStorageInterface {
  
  /**
   * Image style replacement memory storage.
   *
   * This value is not stored in the backend. It's used during the deletion of
   * an image style to save the replacement image style in the same request. The
   * value is used later, when resolving dependencies.
   *
   * @var string[]
   *
   * @see \Drupal\image\Form\ImageStyleDeleteForm::submitForm()
   */
  protected $replacement = [];
  
  /**
   * {@inheritdoc}
   */
  public function setReplacementId($name, $replacement) {
    $this->replacement[$name] = $replacement;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getReplacementId($name) {
    return $this->replacement[$name] ?? NULL;
  }
  
  /**
   * {@inheritdoc}
   */
  public function clearReplacementId($name) {
    unset($this->replacement[$name]);
  }

}