Have ScriptPromiseResolver on the Oilpan heap always.

Source/modules/permissions/PermissionCallback.h

 // Copyright 2015 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.
 
 #ifndef PermissionCallback_h
 #define PermissionCallback_h
 
 #include "platform/heap/Handle.h"
 #include "public/platform/WebCallbacks.h"
 #include "public/platform/modules/permissions/WebPermissionStatus.h"
 #include "public/platform/modules/permissions/WebPermissionType.h"
 #include "wtf/Noncopyable.h"
-#include "wtf/PassRefPtr.h"
-#include "wtf/RefPtr.h"
 
 namespace blink {
 
 class ScriptPromiseResolver;
 
 // PermissionQueryCallback is an implementation of WebPermissionCallbacks
 // that will resolve the underlying promise depending on the result passed to
 // the callback. It takes a WebPermissionType in its constructor and will pass
 // it to the PermissionStatus.
 class PermissionCallback final
     : public WebCallbacks<WebPermissionStatus*, void> {
 public:
-    PermissionCallback(PassRefPtr<ScriptPromiseResolver>, WebPermissionType);
+    PermissionCallback(ScriptPromiseResolver*, WebPermissionType);
     ~PermissionCallback() override;
 
     void onSuccess(WebPermissionStatus*) override;
     void onError() override;
 
 private:
-    RefPtr<ScriptPromiseResolver> m_resolver;
+    Persistent<ScriptPromiseResolver> m_resolver;
     WebPermissionType m_permissionType;
 
     WTF_MAKE_NONCOPYABLE(PermissionCallback);
 };
 
 } // namespace blink
 
 #endif // PermissionCallback_h