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

Source/core/html/shadow/MediaControls.h

 /*
  * Copyright (C) 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011, 2012 Google 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
@@ skipping 48 matching lines @@
 
     void changedClosedCaptionsVisibility();
     void refreshClosedCaptionsButtonVisibility();
     void closedCaptionTracksChanged();
 
     void enteredFullscreen();
     void exitedFullscreen();
 
     void updateTextTrackDisplay();
 
+    void mediaElementFocused();
+
     virtual void trace(Visitor*) OVERRIDE;
 
 private:
     explicit MediaControls(HTMLMediaElement&);
 
     bool initializeControls();
 
     void makeOpaque();
     void makeTransparent();
 
     void updatePlayState();
 
-    bool shouldHideMediaControls();
+    enum HideBehaviorFlags {
+        IgnoreVideoHover = 1 << 0,
+        IgnoreFocus = 1 << 1
+    };
+
+    bool shouldHideMediaControls(unsigned behaviorFlags = 0) const;
     void hideMediaControlsTimerFired(Timer<MediaControls>*);
     void startHideMediaControlsTimer();
     void stopHideMediaControlsTimer();
 
     void createTextTrackDisplay();
     void showTextTrackDisplay();
     void hideTextTrackDisplay();
 
     // Node
     virtual bool isMediaControls() const OVERRIDE { return true; }
@@ skipping 28 matching lines @@
     Timer<MediaControls> m_hideMediaControlsTimer;
     bool m_isMouseOverControls : 1;
     bool m_isPausedForScrubbing : 1;
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(MediaControls, isMediaControls());
 
 }
 
 #endif