Remove unnecessary dependency upon ScrollView from the ScrollbarTheme classes.

Source/core/platform/ScrollbarTheme.cpp

 /*
  * Copyright (C) 2011 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 273 matching lines @@
     IntRect constrainedTrackRect = constrainTrackRectToTrackPieces(scrollbar, trackRect(scrollbar));
     return (scrollbar->orientation() == HorizontalScrollbar) ? constrainedTrackRect.x() - scrollbar->x() : constrainedTrackRect.y() - scrollbar->y();
 }
 
 int ScrollbarTheme::trackLength(ScrollbarThemeClient* scrollbar)
 {
     IntRect constrainedTrackRect = constrainTrackRectToTrackPieces(scrollbar, trackRect(scrollbar));
     return (scrollbar->orientation() == HorizontalScrollbar) ? constrainedTrackRect.width() : constrainedTrackRect.height();
 }
 
-void ScrollbarTheme::paintScrollCorner(ScrollView*, GraphicsContext* context, const IntRect& cornerRect)
+void ScrollbarTheme::paintScrollCorner(GraphicsContext* context, const IntRect& cornerRect)
 {
     context->fillRect(cornerRect, Color::white);
 }
 
 IntRect ScrollbarTheme::thumbRect(ScrollbarThemeClient* scrollbar)
 {
     if (!hasThumb(scrollbar))
         return IntRect();
 
     IntRect track = trackRect(scrollbar);
     IntRect startTrackRect;
     IntRect thumbRect;
     IntRect endTrackRect;
     splitTrack(scrollbar, track, startTrackRect, thumbRect, endTrackRect);
 
     return thumbRect;
 }
 
 int ScrollbarTheme::thumbThickness(ScrollbarThemeClient* scrollbar)
 {
     IntRect track = trackRect(scrollbar);
     return scrollbar->orientation() == HorizontalScrollbar ? track.height() : track.width();
 }
 
-void ScrollbarTheme::paintOverhangBackground(ScrollView*, GraphicsContext* context, const IntRect& horizontalOverhangRect, const IntRect& verticalOverhangRect, const IntRect& dirtyRect)
+void ScrollbarTheme::paintOverhangBackground(GraphicsContext* context, const IntRect& horizontalOverhangRect, const IntRect& verticalOverhangRect, const IntRect& dirtyRect)
 {
     context->setFillColor(Color::white);
     if (!horizontalOverhangRect.isEmpty())
         context->fillRect(intersection(horizontalOverhangRect, dirtyRect));
     if (!verticalOverhangRect.isEmpty())
         context->fillRect(intersection(verticalOverhangRect, dirtyRect));
 }
 
 }