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

Source/core/html/HTMLMediaElement.cpp

 /*
  * 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 3627 matching lines @@
 void HTMLMediaElement::mediaPlayerMediaSourceOpened(blink::WebMediaSource* webMediaSource)
 {
     m_mediaSource->setWebMediaSourceAndOpen(adoptPtr(webMediaSource));
 }
 
 bool HTMLMediaElement::isInteractiveContent() const
 {
     return fastHasAttribute(controlsAttr);
 }
 
+void HTMLMediaElement::defaultEventHandler(Event* event)
+{
+    if (event->type() == EventTypeNames::focusin) {
+        if (hasMediaControls())
+            mediaControls()->mediaElementFocused();
+    }
+    HTMLElement::defaultEventHandler(event);
+}
+
 void HTMLMediaElement::trace(Visitor* visitor)
 {
     visitor->trace(m_error);
     visitor->trace(m_currentSourceNode);
     visitor->trace(m_nextChildNodeToConsider);
     visitor->trace(m_textTracks);
     visitor->trace(m_textTracksWhenResourceSelectionBegan);
     WillBeHeapSupplementable<HTMLMediaElement>::trace(visitor);
     HTMLElement::trace(visitor);
 }
 
 }