Overlay scrollbars flush with window edge

third_party/WebKit/Source/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 180 matching lines @@
   // Otherwise, the ScrollableArea may redraw using cached renderings of
   // individual parts. For instance, if the scrollbar is composited, the thumb
   // may be cached in a GPU texture (and is only guaranteed to be repainted if
   // ThumbPart is invalidated).
   //
   // Even if no parts are invalidated, the scrollbar may need to be redrawn
   // if, for instance, the thumb moves without changing the appearance of any
   // part.
   void setNeedsPaintInvalidation(ScrollbarPart invalidParts);
 
+  bool hasScrollCorner() const;
+
   // Promptly unregister from the theme manager + run finalizers of derived
   // Scrollbars.
   EAGERLY_FINALIZE();
   DECLARE_EAGER_FINALIZATION_OPERATOR_NEW();
   DECLARE_VIRTUAL_TRACE();
 
  protected:
   Scrollbar(ScrollableArea*,
             ScrollbarOrientation,
             ScrollbarControlSize,
@@ skipping 40 matching lines @@
   }
 
   float scrollableAreaCurrentPos() const;
   float scrollableAreaTargetPos() const;
   bool thumbWillBeUnderMouse() const;
 
   int m_themeScrollbarThickness;
   bool m_trackNeedsRepaint;
   bool m_thumbNeedsRepaint;
   LayoutRect m_visualRect;
+  bool m_hitBeginOrEnd;
 };
 
 DEFINE_TYPE_CASTS(Scrollbar,
                   FrameViewBase,
                   frameViewBase,
                   frameViewBase->isScrollbar(),
                   frameViewBase.isScrollbar());
 
 }  // namespace blink
 
 #endif  // Scrollbar_h