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

code from pantheon

* code from pantheon

wp/wp-content/plugins/wordpress-seo/src/helpers/schema/id-helper.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace Yoast\WP\SEO\Helpers\Schema;
+
+use Yoast\WP\SEO\Config\Schema_IDs;
+use Yoast\WP\SEO\Context\Meta_Tags_Context;
+
+/**
+ * Schema utility functions.
+ */
+class ID_Helper {
+
+	/**
+	 * Retrieve a users Schema ID.
+	 *
+	 * @param int               $user_id The ID of the User you need a Schema ID for.
+	 * @param Meta_Tags_Context $context A value object with context variables.
+	 *
+	 * @return string The user's schema ID.
+	 */
+	public function get_user_schema_id( $user_id, $context ) {
+		$user = \get_userdata( $user_id );
+		if ( \is_a( $user, 'WP_User' ) ) {
+			return $context->site_url . Schema_IDs::PERSON_HASH . \wp_hash( $user->user_login . $user_id );
+		}
+
+		return '';
+	}
+}