service worker: Plumb NavigationPreloadManager.enable/disable to browser-side

content/browser/service_worker/service_worker_registration.h

Index: content/browser/service_worker/service_worker_registration.h
diff --git a/content/browser/service_worker/service_worker_registration.h b/content/browser/service_worker/service_worker_registration.h
index 8a69821a962e97204ebe555b4a357c396c75c41a..12bd008d8c031701502ce2bbfa9a52ac2b9773a6 100644
--- a/content/browser/service_worker/service_worker_registration.h
+++ b/content/browser/service_worker/service_worker_registration.h
@@ -150,6 +150,8 @@ class CONTENT_EXPORT ServiceWorkerRegistration
   void SetTaskRunnerForTest(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner);
 
+  void EnableNavigationPreload(bool enable);
+
  private:
   friend class base::RefCounted<ServiceWorkerRegistration>;
 
@@ -192,6 +194,7 @@ class CONTENT_EXPORT ServiceWorkerRegistration
   bool is_uninstalling_;
   bool is_uninstalled_;
   bool should_activate_when_ready_;
+  bool is_navigation_preload_enabled_;
   base::Time last_update_check_;
   int64_t resources_total_size_bytes_;