diff --git a/core/modules/system/src/Form/ThemeSettingsForm.php b/core/modules/system/src/Form/ThemeSettingsForm.php
index 6d9a143..38fa098 100644
--- a/core/modules/system/src/Form/ThemeSettingsForm.php
+++ b/core/modules/system/src/Form/ThemeSettingsForm.php
@@ -17,6 +17,7 @@
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Form\ConfigFormBase;
+use Drupal\Core\File\FileSystemInterface;
 
 /**
  * Displays theme configuration for entire site and individual themes.
@@ -38,6 +39,12 @@ class ThemeSettingsForm extends ConfigFormBase {
   protected $themeHandler;
 
   /**
+   * File System instance.
+   * @var \Drupal\Core\File\FileSystemInterface
+   */
+  protected $fileSystem;
+
+  /**
    * The MIME type guesser.
    *
    * @var \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface
@@ -62,13 +69,16 @@ class ThemeSettingsForm extends ConfigFormBase {
    *   The theme handler.
    * @param \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface $mime_type_guesser
    *   The MIME type guesser instance to use.
+   * @param \Drupal\Core\File\FileSystemInterface $file_system
+   *   The FileSytem instance to use.
    */
-  public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, ThemeHandlerInterface $theme_handler, MimeTypeGuesserInterface $mime_type_guesser) {
+  public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, ThemeHandlerInterface $theme_handler, MimeTypeGuesserInterface $mime_type_guesser, FileSystemInterface $file_system) {
     parent::__construct($config_factory);
 
     $this->moduleHandler = $module_handler;
     $this->themeHandler = $theme_handler;
     $this->mimeTypeGuesser = $mime_type_guesser;
+    $this->fileSystem = $file_system;
   }
 
   /**
@@ -79,7 +89,8 @@ public static function create(ContainerInterface $container) {
       $container->get('config.factory'),
       $container->get('module_handler'),
       $container->get('theme_handler'),
-      $container->get('file.mime_type.guesser')
+      $container->get('file.mime_type.guesser'),
+      $container->get('file_system')
     );
   }
 
@@ -466,7 +477,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
    */
   protected function validatePath($path) {
     // Absolute local file paths are invalid.
-    if (\Drupal::service('file_system')->realpath($path) == $path) {
+    if ($this->fileSystem->realpath($path) == $path) {
       return FALSE;
     }
     // A path relative to the Drupal root or a fully qualified URI is valid.
diff --git a/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php b/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
index d68fe03..08b2f5b 100644
--- a/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
+++ b/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
@@ -10,6 +10,7 @@
 use Drupal\Component\Utility\Color;
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\File\FileSystemInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\ImageToolkit\ImageToolkitBase;
 use Drupal\Core\ImageToolkit\ImageToolkitOperationManagerInterface;
@@ -65,6 +66,13 @@ class GDToolkit extends ImageToolkitBase {
   protected $streamWrapperManager;
 
   /**
+   * File System instance.
+   *
+   * @var \Drupal\Core\File\FileSystemInterface
+   */
+  protected $fileSystem;
+
+  /**
    * Constructs a GDToolkit object.
    *
    * @param array $configuration
@@ -81,10 +89,13 @@ class GDToolkit extends ImageToolkitBase {
    *   The config factory.
    * @param \Drupal\Core\StreamWrapper\StreamWrapperManagerInterface $stream_wrapper_manager
    *   The StreamWrapper manager.
+   * @param \Drupal\Core\File\FileSystemInterface $file_system
+   *   The FileSytem instance to use.
    */
-  public function __construct(array $configuration, $plugin_id, array $plugin_definition, ImageToolkitOperationManagerInterface $operation_manager, LoggerInterface $logger, ConfigFactoryInterface $config_factory, StreamWrapperManagerInterface $stream_wrapper_manager) {
+  public function __construct(array $configuration, $plugin_id, array $plugin_definition, ImageToolkitOperationManagerInterface $operation_manager, LoggerInterface $logger, ConfigFactoryInterface $config_factory, StreamWrapperManagerInterface $stream_wrapper_manager, FileSystemInterface $file_system) {
     parent::__construct($configuration, $plugin_id, $plugin_definition, $operation_manager, $logger, $config_factory);
     $this->streamWrapperManager = $stream_wrapper_manager;
+    $this->fileSystem = $file_system;
   }
 
   /**
@@ -109,7 +120,8 @@ public static function create(ContainerInterface $container, array $configuratio
       $container->get('image.toolkit.operation.manager'),
       $container->get('logger.channel.image'),
       $container->get('config.factory'),
-      $container->get('stream_wrapper_manager')
+      $container->get('stream_wrapper_manager'),
+      $container->get('file_system')
     );
   }
 
@@ -229,7 +241,7 @@ public function save($destination) {
         $destination = drupal_tempnam('temporary://', 'gd_');
       }
       // Convert stream wrapper URI to normal path.
-      $destination = \Drupal::service('file_system')->realpath($destination);
+      $destination = $this->fileSystem->realpath($destination);
     }
 
     $function = 'image' . image_type_to_extension($this->getType(), FALSE);
diff --git a/core/modules/system/src/Tests/File/DirectoryTest.php b/core/modules/system/src/Tests/File/DirectoryTest.php
index 4c15a8e..c5913df 100644
--- a/core/modules/system/src/Tests/File/DirectoryTest.php
+++ b/core/modules/system/src/Tests/File/DirectoryTest.php
@@ -49,7 +49,7 @@ function testFileCheckLocalDirectoryHandling() {
     $this->assertDirectoryPermissions($directory, $old_mode);
 
     // Check creating a directory using an absolute path.
-    $absolute_path = drupal_realpath($directory) . DIRECTORY_SEPARATOR . $this->randomMachineName() . DIRECTORY_SEPARATOR . $this->randomMachineName();
+    $absolute_path = $this->container->get('file_system')->realpath($directory) . DIRECTORY_SEPARATOR . $this->randomMachineName() . DIRECTORY_SEPARATOR . $this->randomMachineName();
     $this->assertTrue(drupal_mkdir($absolute_path, 0775, TRUE), 'No error reported when creating new absolute directories.', 'File');
     $this->assertDirectoryPermissions($absolute_path, 0775);
   }
diff --git a/core/modules/update/src/Form/UpdateReady.php b/core/modules/update/src/Form/UpdateReady.php
index 0beafd1..fa31149 100644
--- a/core/modules/update/src/Form/UpdateReady.php
+++ b/core/modules/update/src/Form/UpdateReady.php
@@ -8,6 +8,7 @@
 namespace Drupal\update\Form;
 
 use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\File\FileSystemInterface;
 use Drupal\Core\FileTransfer\Local;
 use Drupal\Core\Form\FormBase;
 use Drupal\Core\Form\FormStateInterface;
@@ -50,6 +51,13 @@ class UpdateReady extends FormBase {
    protected $sitePath;
 
   /**
+   * File System instance.
+   *
+   * @var \Drupal\Core\File\FileSystemInterface
+   */
+  protected $fileSystem;
+
+  /**
    * Constructs a new UpdateReady object.
    *
    * @param string $root
@@ -60,12 +68,15 @@ class UpdateReady extends FormBase {
    *   The state key value store.
    * @param string $site_path
    *   The site path.
+   * @param \Drupal\Core\File\FileSystemInterface $file_system
+   *   The FileSytem instance to use.
    */
-  public function __construct($root, ModuleHandlerInterface $module_handler, StateInterface $state, $site_path) {
+  public function __construct($root, ModuleHandlerInterface $module_handler, StateInterface $state, $site_path, FileSystemInterface $file_system) {
     $this->root = $root;
     $this->moduleHandler = $module_handler;
     $this->state = $state;
     $this->sitePath = $site_path;
+    $this->fileSystem = $file_system;
   }
 
   /**
@@ -83,7 +94,8 @@ public static function create(ContainerInterface $container) {
       $container->get('update.root'),
       $container->get('module_handler'),
       $container->get('state'),
-      $container->get('site.path')
+      $container->get('site.path'),
+      $container->get('file_system')
     );
   }
 
@@ -141,7 +153,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
       foreach ($projects as $project => $url) {
         $project_location = $directory . '/' . $project;
         $updater = Updater::factory($project_location, $this->root);
-        $project_real_location = \Drupal::service('file_system')->realpath($project_location);
+        $project_real_location = $this->fileSystem->realpath($project_location);
         $updates[] = array(
           'project' => $project,
           'updater_name' => get_class($updater),