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

Source/core/rendering/RenderTableRow.cpp

 /**
  * 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, 2008, 2009, 2010 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 95 matching lines @@
     return style()->borderEnd();
 }
 
 void RenderTableRow::addChild(RenderObject* child, RenderObject* beforeChild)
 {
     if (!child->isTableCell()) {
         RenderObject* last = beforeChild;
         if (!last)
             last = lastChild();
         if (last && last->isAnonymous() && last->isTableCell() && !last->isBeforeOrAfterContent()) {
-            if (beforeChild == last)
-                beforeChild = last->firstChild();
-            last->addChild(child, beforeChild);
+            RenderTableCell* lastCell = toRenderTableCell(last);
+            if (beforeChild == lastCell)
+                beforeChild = lastCell->firstChild();
+            lastCell->addChild(child, beforeChild);
             return;
         }
 
         if (beforeChild && !beforeChild->isAnonymous() && beforeChild->parent() == this) {
             RenderObject* cell = beforeChild->previousSibling();
             if (cell && cell->isTableCell() && cell->isAnonymous()) {
                 cell->addChild(child);
                 return;
             }
         }
@@ skipping 135 matching lines @@
 
 RenderTableRow* RenderTableRow::createAnonymousWithParentRenderer(const RenderObject* parent)
 {
     RenderTableRow* newRow = RenderTableRow::createAnonymous(&parent->document());
     RefPtr<RenderStyle> newStyle = RenderStyle::createAnonymousStyleWithDisplay(parent->style(), TABLE_ROW);
     newRow->setStyle(newStyle.release());
     return newRow;
 }
 
 } // namespace WebCore