Service Worker: Use ScriptPromise instead of ScriptPromise&.

Source/modules/serviceworkers/FetchEvent.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 "FetchEvent.h"
 
 #include "modules/fetch/Request.h"
 #include "modules/serviceworkers/ServiceWorkerGlobalScope.h"
 #include "wtf/RefPtr.h"
@@ skipping 18 matching lines @@
 Request* FetchEvent::request() const
 {
     return m_request;
 }
 
 bool FetchEvent::isReload() const
 {
     return m_isReload;
 }
 
-void FetchEvent::respondWith(ScriptState* scriptState, ScriptPromise& responsePromise, ExceptionState& exceptionState)
+void FetchEvent::respondWith(ScriptState* scriptState, ScriptPromise responsePromise, ExceptionState& exceptionState)
 {
     stopImmediatePropagation();
     m_observer->respondWith(scriptState, responsePromise, exceptionState);
 }
 
 const AtomicString& FetchEvent::interfaceName() const
 {
     return EventNames::FetchEvent;
 }
 
@@ skipping 12 matching lines @@
 }
 
 DEFINE_TRACE(FetchEvent)
 {
     visitor->trace(m_observer);
     visitor->trace(m_request);
     ExtendableEvent::trace(visitor);
 }
 
 } // namespace blink