Implement interfaces in PaintInfo and make it a class.

Source/core/rendering/RenderMediaControls.h

 /*
  * Copyright (C) 2009 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 12 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef RenderMediaControls_h
 #define RenderMediaControls_h
 
 #include "core/html/shadow/MediaControlElements.h"
 
 namespace WebCore {
 
-struct PaintInfo;
+class PaintInfo;
 
 class HTMLMediaElement;
 class IntRect;
 class IntSize;
 class RenderBox;
 class RenderObject;
 class RenderStyle;
 
 class RenderMediaControls {
 public:
 };
 
 } // namespace WebCore
 
 #endif // RenderMediaControls_h