Oilpan: dispose ServiceWorker (and registration) objects earlier.

Source/modules/serviceworkers/ServiceWorker.h

Index: Source/modules/serviceworkers/ServiceWorker.h
diff --git a/Source/modules/serviceworkers/ServiceWorker.h b/Source/modules/serviceworkers/ServiceWorker.h
index b236482cbafe8beb81e43ad9f11ffe157f3004c1..fb4f9a8e5ef57db15ca49b295ee78529effe758d 100644
--- a/Source/modules/serviceworkers/ServiceWorker.h
+++ b/Source/modules/serviceworkers/ServiceWorker.h
@@ -47,12 +47,15 @@ class ScriptPromiseResolver;
 
 class ServiceWorker final : public AbstractWorker, public WebServiceWorkerProxy {
     DEFINE_WRAPPERTYPEINFO();
+    WILL_BE_USING_PRE_FINALIZER(ServiceWorker, dispose);
 public:
     // For CallbackPromiseAdapter
     typedef WebServiceWorker WebType;
     static PassRefPtrWillBeRawPtr<ServiceWorker> take(ScriptPromiseResolver*, WebType* worker);
 
     static PassRefPtrWillBeRawPtr<ServiceWorker> from(ExecutionContext*, WebType*);
+
+    ~ServiceWorker() override;
     static void dispose(WebType*);
 
     void postMessage(ExecutionContext*, PassRefPtr<SerializedScriptValue> message, const MessagePortArray*, ExceptionState&);
@@ -90,6 +93,8 @@ private:
     virtual bool hasPendingActivity() const override;
     virtual void stop() override;
 
+    void dispose();
+
     OwnPtr<WebServiceWorker> m_outerWorker;
     ProxyState m_proxyState;
 };