diff --git a/core/modules/book/book.services.yml b/core/modules/book/book.services.yml
index 06affbb..0928d4a 100644
--- a/core/modules/book/book.services.yml
+++ b/core/modules/book/book.services.yml
@@ -26,8 +26,8 @@ services:
   cache_context.route.book_navigation:
     class: Drupal\book\Cache\BookNavigationCacheContext
     arguments: ['@request_stack']
-    calls:
-      - [setContainer, ['@service_container']]
+    # @todo Remove in https://www.drupal.org/node/2550447.
+    parent: container.trait
     tags:
       - { name: cache.context}
 
diff --git a/core/modules/book/src/Cache/BookNavigationCacheContext.php b/core/modules/book/src/Cache/BookNavigationCacheContext.php
index d165b95..f720484 100644
--- a/core/modules/book/src/Cache/BookNavigationCacheContext.php
+++ b/core/modules/book/src/Cache/BookNavigationCacheContext.php
@@ -65,6 +65,7 @@ public function getContext() {
       return 'book.none';
     }
 
+    // @todo Inject the book.manager in https://www.drupal.org/node/2550447.
     // If we're looking at a book node, get the trail for that node.
     $active_trail = $this->container->get('book.manager')
       ->getActiveTrailIds($node->book['bid'], $node->book);