diff --git a/core/lib/Drupal/Core/ProxyClass/File/MimeType/ExtensionMimeTypeGuesser.php b/core/lib/Drupal/Core/ProxyClass/File/MimeType/ExtensionMimeTypeGuesser.php
index a2eda15..b5f6f50 100644
--- a/core/lib/Drupal/Core/ProxyClass/File/MimeType/ExtensionMimeTypeGuesser.php
+++ b/core/lib/Drupal/Core/ProxyClass/File/MimeType/ExtensionMimeTypeGuesser.php
@@ -79,14 +79,6 @@ public function guess($path)
             return $this->lazyLoadItself()->guess($path);
         }
 
-        /**
-         * {@inheritdoc}
-         */
-        public function setMapping(array $mapping = NULL)
-        {
-            return $this->lazyLoadItself()->setMapping($mapping);
-        }
-
     }
 
 }
diff --git a/core/lib/Drupal/Core/ProxyClass/File/MimeType/MimeTypeMapper.php b/core/lib/Drupal/Core/ProxyClass/File/MimeType/MimeTypeMapper.php
new file mode 100644
index 0000000..519cd95
--- /dev/null
+++ b/core/lib/Drupal/Core/ProxyClass/File/MimeType/MimeTypeMapper.php
@@ -0,0 +1,132 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Core\ProxyClass\File\MimeType\MimeTypeMapper.
+ */
+
+/**
+ * This file was generated via php core/scripts/generate-proxy-class.php 'Drupal\Core\File\MimeType\MimeTypeMapper' "core/lib/Drupal/Core".
+ */
+
+namespace Drupal\Core\ProxyClass\File\MimeType {
+
+    /**
+     * Provides a proxy class for \Drupal\Core\File\MimeType\MimeTypeMapper.
+     *
+     * @see \Drupal\Component\ProxyBuilder
+     */
+    class MimeTypeMapper implements \Drupal\Core\File\MimeType\MimeTypeMapperInterface
+    {
+
+        use \Drupal\Core\DependencyInjection\DependencySerializationTrait;
+
+        /**
+         * The id of the original proxied service.
+         *
+         * @var string
+         */
+        protected $drupalProxyOriginalServiceId;
+
+        /**
+         * The real proxied service, after it was lazy loaded.
+         *
+         * @var \Drupal\Core\File\MimeType\MimeTypeMapper
+         */
+        protected $service;
+
+        /**
+         * The service container.
+         *
+         * @var \Symfony\Component\DependencyInjection\ContainerInterface
+         */
+        protected $container;
+
+        /**
+         * Constructs a ProxyClass Drupal proxy object.
+         *
+         * @param \Symfony\Component\DependencyInjection\ContainerInterface $container
+         *   The container.
+         * @param string $drupal_proxy_original_service_id
+         *   The service ID of the original service.
+         */
+        public function __construct(\Symfony\Component\DependencyInjection\ContainerInterface $container, $drupal_proxy_original_service_id)
+        {
+            $this->container = $container;
+            $this->drupalProxyOriginalServiceId = $drupal_proxy_original_service_id;
+        }
+
+        /**
+         * Lazy loads the real service from the container.
+         *
+         * @return object
+         *   Returns the constructed real service.
+         */
+        protected function lazyLoadItself()
+        {
+            if (!isset($this->service)) {
+                $this->service = $this->container->get($this->drupalProxyOriginalServiceId);
+            }
+
+            return $this->service;
+        }
+
+        /**
+         * {@inheritdoc}
+         */
+        public function alterMapping(\Drupal\Core\Extension\ModuleHandlerInterface $module_handler)
+        {
+            return $this->lazyLoadItself()->alterMapping($module_handler);
+        }
+
+        /**
+         * {@inheritdoc}
+         */
+        public function addMapping($mimetype, $extension)
+        {
+            return $this->lazyLoadItself()->addMapping($mimetype, $extension);
+        }
+
+        /**
+         * {@inheritdoc}
+         */
+        public function removeMapping($extension)
+        {
+            return $this->lazyLoadItself()->removeMapping($extension);
+        }
+
+        /**
+         * {@inheritdoc}
+         */
+        public function removeMimeType($mimetype)
+        {
+            return $this->lazyLoadItself()->removeMimeType($mimetype);
+        }
+
+        /**
+         * {@inheritdoc}
+         */
+        public function getMimeTypes()
+        {
+            return $this->lazyLoadItself()->getMimeTypes();
+        }
+
+        /**
+         * {@inheritdoc}
+         */
+        public function getMimeTypeForExtension($extension)
+        {
+            return $this->lazyLoadItself()->getMimeTypeForExtension($extension);
+        }
+
+        /**
+         * {@inheritdoc}
+         */
+        public function getExtensionsForMimeType($mimetype)
+        {
+            return $this->lazyLoadItself()->getExtensionsForMimeType($mimetype);
+        }
+
+    }
+
+}