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

Source/core/dom/Text.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 259 matching lines @@
         if (prev && !prev->isInline())
             return false;
     } else {
         if (parent.isRenderBlock() && !parent.childrenInline() && (!prev || !prev->isInline()))
             return false;
 
         // Avoiding creation of a Renderer for the text node is a non-essential memory optimization.
         // So to avoid blowing up on very wide DOMs, we limit the number of siblings to visit.
         unsigned maxSiblingsToVisit = 50;
 
-        RenderObject* first = parent.firstChild();
+        RenderObject* first = parent.slowFirstChild();
         while (first && first->isFloatingOrOutOfFlowPositioned() && maxSiblingsToVisit--)
             first = first->nextSibling();
         if (!first || NodeRenderingTraversal::nextSiblingRenderer(this) == first)
             // Whitespace at the start of a block just goes away.  Don't even
             // make a render object for this text.
             return false;
     }
     return true;
 }
 
@@ skipping 79 matching lines @@
             result.appendLiteral("; ");
         result.appendLiteral("value=");
         result.append(s);
     }
 
     strncpy(buffer, result.toString().utf8().data(), length - 1);
 }
 #endif
 
 } // namespace WebCore