Have ScriptPromiseResolver on the Oilpan heap always.

Source/modules/presentation/Presentation.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 "modules/presentation/Presentation.h"
 
 #include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
@@ skipping 69 matching lines @@
     DOMWindowProperty::trace(visitor);
 }
 
 PresentationSession* Presentation::session() const
 {
     return m_session.get();
 }
 
 ScriptPromise Presentation::startSession(ScriptState* state, const String& presentationUrl)
 {
-    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(state);
+    ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(state);
     ScriptPromise promise = resolver->promise();
 
     WebPresentationClient* client = presentationClient(executionContext());
     if (!client) {
         resolver->reject(DOMException::create(InvalidStateError, "The object is no longer attached to the frame."));
         return promise;
     }
     client->startSession(presentationUrl, new PresentationSessionClientCallbacks(resolver, this));
 
     return promise;
 }
 
 ScriptPromise Presentation::joinSession(ScriptState* state, const String& presentationUrl, const String& presentationId)
 {
-    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(state);
+    ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(state);
     ScriptPromise promise = resolver->promise();
 
     WebPresentationClient* client = presentationClient(executionContext());
     if (!client) {
         resolver->reject(DOMException::create(InvalidStateError, "The object is no longer attached to the frame."));
         return promise;
     }
     client->joinSession(presentationUrl, presentationId, new PresentationSessionClientCallbacks(resolver, this));
 
     return promise;
 }
 
 ScriptPromise Presentation::getAvailability(ScriptState* state, const String& presentationUrl)
 {
-    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(state);
+    ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(state);
     ScriptPromise promise = resolver->promise();
 
     WebPresentationClient* client = presentationClient(executionContext());
     if (!client) {
         resolver->reject(DOMException::create(InvalidStateError, "The object is no longer attached to the frame."));
         return promise;
     }
     client->getAvailability(presentationUrl, new PresentationAvailabilityCallback(resolver));
 
     return promise;
@@ skipping 59 matching lines @@
 PresentationSession* Presentation::findSession(WebPresentationSessionClient* sessionClient)
 {
     for (const auto& session : m_openSessions) {
         if (session->matches(sessionClient))
             return session.get();
     }
     return nullptr;
 }
 
 } // namespace blink