Trace where timers were scheduled in Blink

Source/core/events/EventSender.h

 /*
  * Copyright (C) 2012 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 50 matching lines @@
 template<typename T> EventSender<T>::EventSender(const AtomicString& eventType)
     : m_eventType(eventType)
     , m_timer(this, &EventSender::timerFired)
 {
 }
 
 template<typename T> void EventSender<T>::dispatchEventSoon(T* sender)
 {
     m_dispatchSoonList.append(sender);
     if (!m_timer.isActive())
-        m_timer.startOneShot(0);
+        m_timer.startOneShot(0, FROM_HERE);
 }
 
 template<typename T> void EventSender<T>::cancelEvent(T* sender)
 {
     // Remove instances of this sender from both lists.
     // Use loops because we allow multiple instances to get into the lists.
     size_t size = m_dispatchSoonList.size();
     for (size_t i = 0; i < size; ++i) {
         if (m_dispatchSoonList[i] == sender)
             m_dispatchSoonList[i] = 0;
@@ skipping 22 matching lines @@
             m_dispatchingList[i] = 0;
             sender->dispatchPendingEvent(this);
         }
     }
     m_dispatchingList.clear();
 }
 
 } // namespace WebCore
 
 #endif // EventSender_h