Constructs a new ViewPreviewFormController object.
string $operation: The name of the current operation.
\Drupal\user\TempStoreFactory $temp_store_factory: The factory for the temp store object.
Overrides EntityFormController::__construct
public function __construct($operation, TempStoreFactory $temp_store_factory) {
parent::__construct($operation);
$this->tempStore = $temp_store_factory
->get('views');
}