EventSender<T> singletons are better off on the Oilpan heap.

third_party/WebKit/Source/core/html/HTMLSourceElement.h

 /*
  * Copyright (C) 2007, 2008, 2010 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 15 matching lines @@
 #ifndef HTMLSourceElement_h
 #define HTMLSourceElement_h
 
 #include "core/css/MediaQueryListListener.h"
 #include "core/html/HTMLElement.h"
 #include "platform/Timer.h"
 
 namespace blink {
 
 template<typename T> class EventSender;
-typedef EventSender<HTMLSourceElement> SourceEventSender;
+using SourceEventSender = EventSender<HTMLSourceElement>;
 
 class HTMLSourceElement final : public HTMLElement {
     DEFINE_WRAPPERTYPEINFO();
 public:
     class Listener;
 
     DECLARE_NODE_FACTORY(HTMLSourceElement);
     ~HTMLSourceElement() override;
 
     const AtomicString& type() const;
@@ skipping 22 matching lines @@
     void notifyMediaQueryChanged();
     void createMediaQueryList(const AtomicString& media);
 
     RefPtrWillBeMember<MediaQueryList> m_mediaQueryList;
     RefPtrWillBeMember<Listener> m_listener;
 };
 
 } // namespace blink
 
 #endif // HTMLSourceElement_h