Implement heuristic for showing media controls during playback w/o a mouse

Source/core/html/HTMLMediaElement.h

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 296 matching lines @@
     virtual bool rendererIsNeeded(const RenderStyle&) OVERRIDE;
     virtual RenderObject* createRenderer(RenderStyle*) OVERRIDE;
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE FINAL;
     virtual void didNotifySubtreeInsertionsToDocument() OVERRIDE;
     virtual void removedFrom(ContainerNode*) OVERRIDE FINAL;
     virtual void didRecalcStyle(StyleRecalcChange) OVERRIDE FINAL;
 
     virtual void didBecomeFullscreenElement() OVERRIDE FINAL;
     virtual void willStopBeingFullscreenElement() OVERRIDE FINAL;
     virtual bool isInteractiveContent() const OVERRIDE FINAL;
+    virtual void defaultEventHandler(Event*) OVERRIDE FINAL;
 
     // ActiveDOMObject functions.
     virtual void stop() OVERRIDE FINAL;
 
     virtual void updateDisplayState() { }
 
     void setReadyState(MediaPlayer::ReadyState);
     void setNetworkState(MediaPlayer::NetworkState);
 
     virtual void mediaPlayerNetworkStateChanged() OVERRIDE FINAL;
@@ skipping 226 matching lines @@
 inline bool isHTMLMediaElement(const HTMLElement& element)
 {
     return isHTMLAudioElement(element) || isHTMLVideoElement(element);
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLMediaElement);
 
 } //namespace
 
 #endif