Make DisplayItemClient an interface

third_party/WebKit/Source/core/layout/LayoutScrollbarTheme.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 93 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 LayoutScrollbarTheme::paintScrollCorner(GraphicsContext* context, const DisplayItemClientWrapper& displayItemClient, const IntRect& cornerRect)
+void LayoutScrollbarTheme::paintScrollCorner(GraphicsContext* context, const DisplayItemClient& displayItemClient, const IntRect& cornerRect)
 {
     if (DrawingRecorder::useCachedDrawingIfPossible(*context, displayItemClient, DisplayItem::ScrollbarCorner))
         return;
 
     DrawingRecorder recorder(*context, displayItemClient, DisplayItem::ScrollbarCorner, cornerRect);
     // FIXME: Implement.
     context->fillRect(cornerRect, Color::white);
 }
 
 void LayoutScrollbarTheme::paintScrollbarBackground(GraphicsContext* context, const ScrollbarThemeClient* scrollbar)
@@ skipping 20 matching lines @@
 {
     ScrollbarPainter(*toLayoutScrollbar(scrollbar)).paintPart(context, ThumbPart, rect);
 }
 
 void LayoutScrollbarTheme::paintTickmarks(GraphicsContext* context, const ScrollbarThemeClient* scrollbar, const IntRect& rect)
 {
     ScrollbarTheme::theme()->paintTickmarks(context, scrollbar, rect);
 }
 
 }