--- /dev/null
+<?php
+
+namespace Drupal\Core\Breadcrumb;
+
+/**
+ * Defines an interface a chained service that builds the breadcrumb.
+ */
+interface ChainBreadcrumbBuilderInterface extends BreadcrumbBuilderInterface {
+
+ /**
+ * Adds another breadcrumb builder.
+ *
+ * @param \Drupal\Core\Breadcrumb\BreadcrumbBuilderInterface $builder
+ * The breadcrumb builder to add.
+ * @param int $priority
+ * Priority of the breadcrumb builder.
+ */
+ public function addBuilder(BreadcrumbBuilderInterface $builder, $priority);
+
+}