service worker: Add NavigationPreload runtime flag and skeleton interface

third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerRegistration.h

Index: third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerRegistration.h
diff --git a/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerRegistration.h b/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerRegistration.h
index 0929fb99334ca56de75f6bb99bdb1ec0b57f819f..17494e691577e9e03a2493646d98b10b4d13738a 100644
--- a/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerRegistration.h
+++ b/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerRegistration.h
@@ -9,6 +9,7 @@
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/ActiveDOMObject.h"
 #include "core/events/EventTarget.h"
+#include "modules/serviceworkers/NavigationPreloadManager.h"
 #include "modules/serviceworkers/ServiceWorker.h"
 #include "modules/serviceworkers/ServiceWorkerRegistration.h"
 #include "platform/Supplementable.h"
@@ -61,6 +62,7 @@ class ServiceWorkerRegistration final
   ServiceWorker* installing() { return m_installing; }
   ServiceWorker* waiting() { return m_waiting; }
   ServiceWorker* active() { return m_active; }
+  NavigationPreloadManager* navigationPreload();
 
   String scope() const;
 
@@ -92,6 +94,7 @@ class ServiceWorkerRegistration final
   Member<ServiceWorker> m_installing;
   Member<ServiceWorker> m_waiting;
   Member<ServiceWorker> m_active;
+  Member<NavigationPreloadManager> m_navigationPreload;
 
   bool m_stopped;
 };