Allow assertions to be enabled in Blink Release builds.

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 24 matching lines @@
 template<typename T> class EventSender {
     WTF_MAKE_NONCOPYABLE(EventSender); WTF_MAKE_FAST_ALLOCATED;
 public:
     explicit EventSender(const AtomicString& eventType);
 
     const AtomicString& eventType() const { return m_eventType; }
     void dispatchEventSoon(T*);
     void cancelEvent(T*);
     void dispatchPendingEvents();
 
-#ifndef NDEBUG
+#if ENABLE(ASSERT)
     bool hasPendingEvents(T* sender) const
     {
         return m_dispatchSoonList.find(sender) != kNotFound || m_dispatchingList.find(sender) != kNotFound;
     }
 #endif
 
 private:
     void timerFired(Timer<EventSender<T> >*) { dispatchPendingEvents(); }
 
     AtomicString m_eventType;
@@ skipping 48 matching lines @@
             m_dispatchingList[i] = nullptr;
             sender->dispatchPendingEvent(this);
         }
     }
     m_dispatchingList.clear();
 }
 
 } // namespace WebCore
 
 #endif // EventSender_h