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

Source/core/rendering/RenderObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google 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 152 matching lines @@
     virtual const char* renderName() const = 0;
 
     String debugName() const;
 
     RenderObject* parent() const { return m_parent; }
     bool isDescendantOf(const RenderObject*) const;
 
     RenderObject* previousSibling() const { return m_previous; }
     RenderObject* nextSibling() const { return m_next; }
 
-    // FIXME: These should be renamed slowFirstChild, slowLastChild, etc.
-    // to discourage their use. The virtualChildren() call inside these
-    // can be slow for hot code paths.
-    // Currently, some subclasses like RenderBlock, override these NON-virtual
-    // functions to make these fast when we already have a more specific pointer type.
-    RenderObject* firstChild() const
+    RenderObject* slowFirstChild() const
     {
         if (const RenderObjectChildList* children = virtualChildren())
             return children->firstChild();
         return 0;
     }
-    RenderObject* lastChild() const
+    RenderObject* slowLastChild() const
     {
         if (const RenderObjectChildList* children = virtualChildren())
             return children->lastChild();
         return 0;
     }
 
     virtual RenderObjectChildList* virtualChildren() { return 0; }
     virtual const RenderObjectChildList* virtualChildren() const { return 0; }
 
     RenderObject* nextInPreOrder() const;
@@ skipping 1283 matching lines @@
 void showTree(const WebCore::RenderObject*);
 void showLineTree(const WebCore::RenderObject*);
 void showRenderTree(const WebCore::RenderObject* object1);
 // We don't make object2 an optional parameter so that showRenderTree
 // can be called from gdb easily.
 void showRenderTree(const WebCore::RenderObject* object1, const WebCore::RenderObject* object2);
 
 #endif
 
 #endif // RenderObject_h