Have ScriptPromiseResolver on the Oilpan heap always.

Source/core/testing/Internals.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 2238 matching lines @@
         ASSERT(v8Value->IsNumber());
         int intValue = v8Value.As<v8::Integer>()->Value();
         return ScriptValue(scriptState(), v8::Integer::New(scriptState()->isolate(), intValue + 1));
     }
 };
 
 } // namespace
 
 ScriptPromise Internals::createResolvedPromise(ScriptState* scriptState, ScriptValue value)
 {
-    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
     resolver->resolve(value);
     return promise;
 }
 
 ScriptPromise Internals::createRejectedPromise(ScriptState* scriptState, ScriptValue value)
 {
-    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
     resolver->reject(value);
     return promise;
 }
 
 ScriptPromise Internals::addOneToPromise(ScriptState* scriptState, ScriptPromise promise)
 {
     return promise.then(AddOneFunction::createFunction(scriptState));
 }
 
@@ skipping 208 matching lines @@
 
     return animator->setScrollbarsVisibleForTesting(visible);
 }
 
 void Internals::forceRestrictIFramePermissions()
 {
     RuntimeEnabledFeatures::setRestrictIFramePermissionsEnabled(true);
 }
 
 } // namespace blink