Implement media cast buttons

Source/core/html/shadow/MediaControlElementTypes.h

 /*
  * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 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.
@@ skipping 45 matching lines @@
     MediaControlsPanel,
     MediaVolumeSliderContainer,
     MediaVolumeSlider,
     MediaVolumeSliderThumb,
     MediaFullScreenVolumeSlider,
     MediaFullScreenVolumeSliderThumb,
     MediaTextTrackDisplayContainer,
     MediaTextTrackDisplay,
     MediaExitFullscreenButton,
     MediaOverlayPlayButton,
+    MediaCastOffButton,
+    MediaCastOnButton,
+    MediaOverlayCastOffButton,
+    MediaOverlayCastOnButton,
 };
 
 HTMLMediaElement* toParentMediaElement(Node*);
 inline HTMLMediaElement* toParentMediaElement(RenderObject* renderer) { return toParentMediaElement(renderer->node()); }
 
 MediaControlElementType mediaControlElementType(Node*);
 
 // ----------------------------
 
 class MediaControlElement : public WillBeGarbageCollectedMixin {
@@ skipping 57 matching lines @@
 protected:
     MediaControlTimeDisplayElement(MediaControls&, MediaControlElementType);
 
 private:
     double m_currentValue;
 };
 
 } // namespace blink
 
 #endif // MediaControlElementTypes_h