Remove WebScroll*

sky/engine/platform/scroll/Scrollbar.h

 /*
  * Copyright (C) 2004, 2006 Apple Computer, 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 100 matching lines @@
 
     void invalidateParts()
     {
         invalidatePart(BackTrackPart);
         invalidatePart(ThumbPart);
         invalidatePart(ForwardTrackPart);
     }
 
     void invalidatePart(ScrollbarPart);
 
-    bool shouldCenterOnThumb(const PlatformMouseEvent&);
-    bool shouldSnapBackToDragOrigin(const PlatformMouseEvent&);
-
     // The position of the thumb relative to the track.
     int thumbPosition();
     // The length of the thumb along the axis of the scrollbar.
     int thumbLength();
     // The position of the track relative to the scrollbar.
     int trackPosition();
     // The length of the track along the axis of the scrollbar.
     int trackLength();
 
     IntRect trackRect();
@@ skipping 44 matching lines @@
     virtual bool isScrollbar() const override { return true; }
 
     float scrollableAreaCurrentPos() const;
 };
 
 DEFINE_TYPE_CASTS(Scrollbar, Widget, widget, widget->isScrollbar(), widget.isScrollbar());
 
 } // namespace blink
 
 #endif // Scrollbar_h