Remove unnecessary dependency upon ScrollView from the ScrollbarTheme classes.

Source/core/rendering/RenderScrollbarTheme.cpp

 /*
  * Copyright (C) 2008 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 89 matching lines @@
     if (scrollbar->orientation() == HorizontalScrollbar) {
         result.setX(backRect.x());
         result.setWidth(forwardRect.maxX() - backRect.x());
     } else {
         result.setY(backRect.y());
         result.setHeight(forwardRect.maxY() - backRect.y());
     }
     return result;
 }
 
-void RenderScrollbarTheme::paintScrollCorner(ScrollView*, GraphicsContext* context, const IntRect& cornerRect)
+void RenderScrollbarTheme::paintScrollCorner(GraphicsContext* context, const IntRect& cornerRect)
 {
     // FIXME: Implement.
     context->fillRect(cornerRect, Color::white);
 }
 
 void RenderScrollbarTheme::paintScrollbarBackground(GraphicsContext* context, ScrollbarThemeClient* scrollbar)
 {
     toRenderScrollbar(scrollbar)->paintPart(context, ScrollbarBGPart, scrollbar->frameRect());
 }
 
@@ skipping 16 matching lines @@
 {
     toRenderScrollbar(scrollbar)->paintPart(context, ThumbPart, rect);
 }
 
 void RenderScrollbarTheme::paintTickmarks(GraphicsContext* context, ScrollbarThemeClient* scrollbar, const IntRect& rect)
 {
     ScrollbarTheme::theme()->paintTickmarks(context, scrollbar, rect);
 }
 
 }