Merged in feature/from-pantheon (pull request #16)

code from pantheon

* code from pantheon

wp/wp-content/plugins/wordpress-seo/src/surfaces/classes-surface.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Yoast\WP\SEO\Surfaces;
+
+use YoastSEO_Vendor\Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Class Classes_Surface.
+ *
+ * Surface for the indexables.
+ */
+class Classes_Surface {
+
+	/**
+	 * The dependency injection container.
+	 *
+	 * @var ContainerInterface
+	 */
+	public $container;
+
+	/**
+	 * Loader constructor.
+	 *
+	 * @param ContainerInterface $container The dependency injection container.
+	 */
+	public function __construct( ContainerInterface $container ) {
+		$this->container = $container;
+	}
+
+	/**
+	 * Returns the instance of a class. Handy for unhooking things.
+	 *
+	 * @param string $class_name The class to get the instance of.
+	 *
+	 * @return mixed The instance of the class.
+	 */
+	public function get( $class_name ) {
+		return $this->container->get( $class_name );
+	}
+}