only in patch2:
unchanged:
--- a/core/modules/file/src/FileUsage/DatabaseFileUsageBackend.php
+++ b/core/modules/file/src/FileUsage/DatabaseFileUsageBackend.php
@@ -9,7 +9,7 @@
 
 use Drupal\Core\Database\Connection;
 use Drupal\Core\Database\DatabaseExceptionWrapper;
-use Drupal\file\Entity\File;
+use Drupal\file\FileInterface;
 
 /**
  * Defines the database file usage backend. This is the default Drupal backend.
@@ -48,7 +48,7 @@ public function __construct(Connection $connection, $table = 'file_usage') {
   /**
    * Implements Drupal\file\FileUsage\FileUsageInterface::add().
    */
-  public function add(File $file, $module, $type, $id, $count = 1) {
+  public function add(FileInterface $file, $module, $type, $id, $count = 1) {
     $this->connection->merge($this->tableName)
       ->keys(array(
         'fid' => $file->id(),
@@ -66,7 +66,7 @@ public function add(File $file, $module, $type, $id, $count = 1) {
   /**
    * Implements Drupal\file\FileUsage\FileUsageInterface::delete().
    */
-  public function delete(File $file, $module, $type = NULL, $id = NULL, $count = 1) {
+  public function delete(FileInterface $file, $module, $type = NULL, $id = NULL, $count = 1) {
     // Delete rows that have a exact or less value to prevent empty rows.
     $query = $this->connection->delete($this->tableName)
       ->condition('module', $module)
@@ -101,7 +101,7 @@ public function delete(File $file, $module, $type = NULL, $id = NULL, $count = 1
   /**
    * Implements Drupal\file\FileUsage\FileUsageInterface::listUsage().
    */
-  public function listUsage(File $file) {
+  public function listUsage(FileInterface $file) {
     $result = $this->connection->select($this->tableName, 'f')
       ->fields('f', array('module', 'type', 'id', 'count'))
       ->condition('fid', $file->id())
only in patch2:
unchanged:
--- a/core/modules/file/src/FileUsage/FileUsageBase.php
+++ b/core/modules/file/src/FileUsage/FileUsageBase.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\file\FileUsage;
 
-use Drupal\file\Entity\File;
+use Drupal\file\FileInterface;
 
 /**
  * Defines the base class for database file usage backend.
@@ -17,7 +17,7 @@
   /**
    * Implements Drupal\file\FileUsage\FileUsageInterface::add().
    */
-  public function add(File $file, $module, $type, $id, $count = 1) {
+  public function add(FileInterface $file, $module, $type, $id, $count = 1) {
     // Make sure that a used file is permanent.
     if (!$file->isPermanent()) {
       $file->setPermanent();
@@ -28,7 +28,7 @@ public function add(File $file, $module, $type, $id, $count = 1) {
   /**
    * Implements Drupal\file\FileUsage\FileUsageInterface::delete().
    */
-  public function delete(File $file, $module, $type = NULL, $id = NULL, $count = 1) {
+  public function delete(FileInterface $file, $module, $type = NULL, $id = NULL, $count = 1) {
     // If there are no more remaining usages of this file, mark it as temporary,
     // which result in a delete through system_cron().
     $usage = \Drupal::service('file.usage')->listUsage($file);
only in patch2:
unchanged:
--- a/core/modules/system/tests/modules/service_provider_test/src/TestFileUsage.php
+++ b/core/modules/system/tests/modules/service_provider_test/src/TestFileUsage.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\service_provider_test;
 
-use Drupal\file\Entity\File;
+use Drupal\file\FileInterface;
 use Drupal\file\FileUsage\FileUsageBase;
 
 class TestFileUsage extends FileUsageBase {
@@ -15,18 +15,18 @@ class TestFileUsage extends FileUsageBase {
   /**
    * Implements Drupal\file\FileUsage\FileUsageInterface::add().
    */
-  public function add(File $file, $module, $type, $id, $count = 1) {
+  public function add(FileInterface $file, $module, $type, $id, $count = 1) {
   }
 
   /**
    * Implements Drupal\file\FileUsage\FileUsageInterface::delete().
    */
-  public function delete(File $file, $module, $type = NULL, $id = NULL, $count = 1) {
+  public function delete(FileInterface $file, $module, $type = NULL, $id = NULL, $count = 1) {
   }
 
   /**
    * Implements Drupal\file\FileUsage\FileUsageInterface::listUsage().
    */
-  public function listUsage(File $file) {
+  public function listUsage(FileInterface $file) {
   }
 }