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

code from pantheon

* code from pantheon

wp/wp-content/plugins/wordpress-seo/src/values/robots/directive.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace Yoast\WP\SEO\Values\Robots;
+
+/**
+ * Class Directive
+ */
+class Directive {
+
+	/**
+	 * Paths list.
+	 *
+	 * @var array All paths affected by this directive.
+	 */
+	private $paths;
+
+	/**
+	 * Sets up the path array
+	 */
+	public function __construct() {
+		$this->paths = [];
+	}
+
+	/**
+	 * Adds a path to the directive path list.
+	 *
+	 * @param string $path A path to add in the path list.
+	 *
+	 * @return void
+	 */
+	public function add_path( $path ) {
+		if ( ! \in_array( $path, $this->paths, true ) ) {
+			$this->paths[] = $path;
+		}
+	}
+
+	/**
+	 * Returns all paths.
+	 *
+	 * @return array
+	 */
+	public function get_paths() {
+		return $this->paths;
+	}
+}