add 'slow' prefix to RenderObject's firstChild() / lastChild() methods

Source/core/rendering/RenderTableSection.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, 2009 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 47 matching lines @@
 };
 
 class RenderTableCell;
 class RenderTableRow;
 
 class RenderTableSection FINAL : public RenderBox {
 public:
     RenderTableSection(Element*);
     virtual ~RenderTableSection();
 
+    // FIXME: These methods should return a RenderTableRow.
     RenderObject* firstChild() const { ASSERT(children() == virtualChildren()); return children()->firstChild(); }
     RenderObject* lastChild() const { ASSERT(children() == virtualChildren()); return children()->lastChild(); }
 
     const RenderObjectChildList* children() const { return &m_children; }
     RenderObjectChildList* children() { return &m_children; }
 
     virtual void addChild(RenderObject* child, RenderObject* beforeChild = 0) OVERRIDE;
 
     virtual int firstLineBoxBaseline() const OVERRIDE;
 
@@ skipping 228 matching lines @@
     // This map holds the collapsed border values for cells with collapsed borders.
     // It is held at RenderTableSection level to spare memory consumption by table cells.
     HashMap<pair<const RenderTableCell*, int>, CollapsedBorderValue > m_cellsCollapsedBorders;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderTableSection, isTableSection());
 
 } // namespace WebCore
 
 #endif // RenderTableSection_h