Factor painting code out of RenderBox into a new class called BoxPainter.

Source/core/rendering/RenderTableCell.h

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2009, 2013 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 272 matching lines @@
     void nextSibling() const WTF_DELETED_FUNCTION;
     void previousSibling() const WTF_DELETED_FUNCTION;
 
     // Note MSVC will only pack members if they have identical types, hence we use unsigned instead of bool here.
     unsigned m_column : 29;
     unsigned m_cellWidthChanged : 1;
     unsigned m_hasColSpan: 1;
     unsigned m_hasRowSpan: 1;
     int m_intrinsicPaddingBefore;
     int m_intrinsicPaddingAfter;
+
+    BoxPainter m_boxPainter;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderTableCell, isTableCell());
 
 inline RenderTableCell* RenderTableCell::previousCell() const
 {
     return toRenderTableCell(RenderObject::previousSibling());
 }
 
 inline RenderTableCell* RenderTableCell::nextCell() const
 {
     return toRenderTableCell(RenderObject::nextSibling());
 }
 
 inline RenderTableCell* RenderTableRow::firstCell() const
 {
     ASSERT(children() == virtualChildren());
     return toRenderTableCell(children()->firstChild());
 }
 
 inline RenderTableCell* RenderTableRow::lastCell() const
 {
     ASSERT(children() == virtualChildren());
     return toRenderTableCell(children()->lastChild());
 }
 
 } // namespace blink
 
 #endif // RenderTableCell_h