Remove getNodesInCommand debug method from Editing commands

Source/core/editing/SetNodeAttributeCommand.cpp

 /*
  * Copyright (C) 2005, 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 36 matching lines @@
     m_element->setAttribute(m_attribute, m_value);
 }
 
 void SetNodeAttributeCommand::doUnapply()
 {
     m_element->setAttribute(m_attribute, m_oldValue);
     StringImpl* nullString = 0;
     m_oldValue = nullString;
 }
 
-#ifndef NDEBUG
-void SetNodeAttributeCommand::getNodesInCommand(HashSet<Node*>& nodes)
-{
-    addNodeAndDescendants(m_element.get(), nodes);
-}
-#endif
-
 } // namespace WebCore