Have ScriptPromiseResolver on the Oilpan heap always.

Source/modules/serviceworkers/ServiceWorkerRegistration.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "ServiceWorkerRegistration.h"
 
 #include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
@@ skipping 79 matching lines @@
 {
     if (!m_provider) {
         exceptionState.throwDOMException(InvalidStateError, "Failed to update a ServiceWorkerRegistration: No associated provider is available.");
         return;
     }
     m_outerRegistration->update(m_provider);
 }
 
 ScriptPromise ServiceWorkerRegistration::unregister(ScriptState* scriptState)
 {
-    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
 
     if (!m_provider) {
         resolver->reject(DOMException::create(InvalidStateError, "Failed to unregister a ServiceWorkerRegistration: No associated provider is available."));
         return promise;
     }
 
     m_outerRegistration->unregister(m_provider, new CallbackPromiseAdapter<bool, ServiceWorkerError>(resolver));
     return promise;
 }
@@ skipping 50 matching lines @@
 
 void ServiceWorkerRegistration::stop()
 {
     if (m_stopped)
         return;
     m_stopped = true;
     m_outerRegistration->proxyStopped();
 }
 
 } // namespace blink