ServiceWorker: Make "ready" fetches registration from browser process(1/3).

Source/modules/serviceworkers/ServiceWorkerContainer.h

Index: Source/modules/serviceworkers/ServiceWorkerContainer.h
diff --git a/Source/modules/serviceworkers/ServiceWorkerContainer.h b/Source/modules/serviceworkers/ServiceWorkerContainer.h
index ea50f78a21daaa1b78981884b5fd958865cd14cc..ef27f2350b4ed95ad69b25da6aaf22933eaa1bd1 100644
--- a/Source/modules/serviceworkers/ServiceWorkerContainer.h
+++ b/Source/modules/serviceworkers/ServiceWorkerContainer.h
@@ -89,6 +89,7 @@ public:
 private:
     explicit ServiceWorkerContainer(ExecutionContext*);
 
+    class GetRegistrationForReadyCallback;
     typedef ScriptPromiseProperty<Member<ServiceWorkerContainer>, Member<ServiceWorkerRegistration>, Member<ServiceWorkerRegistration>> ReadyProperty;
     ReadyProperty* createReadyProperty();