Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/symfony/http-kernel/DependencyInjection/Extension.php

@@ -0,0 +1,44 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpKernel\DependencyInjection;
+
+use Symfony\Component\DependencyInjection\Extension\Extension as BaseExtension;
+
+/**
+ * Allow adding classes to the class cache.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+abstract class Extension extends BaseExtension
+{
+    private $classes = array();
+
+    /**
+     * Gets the classes to cache.
+     *
+     * @return array An array of classes
+     */
+    public function getClassesToCompile()
+    {
+        return $this->classes;
+    }
+
+    /**
+     * Adds classes to the class cache.
+     *
+     * @param array $classes An array of classes
+     */
+    public function addClassesToCompile(array $classes)
+    {
+        $this->classes = array_merge($this->classes, $classes);
+    }
+}