Remove getNodesInCommand debug method from Editing commands

Source/core/editing/AppendNodeCommand.h

 /*
  * Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 25 matching lines @@
     {
         return adoptRef(new AppendNodeCommand(parent, node));
     }
 
 private:
     AppendNodeCommand(PassRefPtr<ContainerNode> parent, PassRefPtr<Node>);
 
     virtual void doApply() OVERRIDE;
     virtual void doUnapply() OVERRIDE;
 
-#ifndef NDEBUG
-    virtual void getNodesInCommand(HashSet<Node*>&) OVERRIDE;
-#endif
-
     RefPtr<ContainerNode> m_parent;
     RefPtr<Node> m_node;
 };
 
 } // namespace WebCore
 
 #endif // AppendNodeCommand_h