3454516: Replace FileSystem injection with FileSystemInterface to allow for decorators.

Closes #3454516

src/Plugin/Field/FieldFormatter/CSVFileFormatter.php

@@ -4,6 +4,7 @@ namespace Drupal\csvfile_formatter\Plugin\Field\FieldFormatter;
 
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\File\FileSystemInterface;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\file\Plugin\Field\FieldFormatter\FileFormatterBase;
 use Drupal\Core\Link;
@@ -29,7 +30,7 @@ class CSVFileFormatter extends FileFormatterBase {
   /**
    * Inject file_system service.
    *
-   * @var \Drupal\Core\File\FileSystem
+   * @var \Drupal\Core\File\FileSystemInterface
    */
   protected $fileSystem;
 
@@ -92,7 +93,7 @@ class CSVFileFormatter extends FileFormatterBase {
   /**
    * {@inheritdoc}
    */
-  public function __construct($plugin_id, $plugin_definition, $field_definition, array $settings, $label, $view_mode, array $third_party_settings, FileSystem $file_system, ConfigFactoryInterface $config_factory, RequestStack $request_stack) {
+  public function __construct($plugin_id, $plugin_definition, $field_definition, array $settings, $label, $view_mode, array $third_party_settings, FileSystemInterface $file_system, ConfigFactoryInterface $config_factory, RequestStack $request_stack) {
     parent::__construct($plugin_id, $plugin_definition, $field_definition, $settings, $label, $view_mode, $third_party_settings);
     $this->setFileSystem($file_system);
     $this->setConfigFactory($config_factory);