Move Node/ContainerNode's traverseToChildAt() to NodeTraversal

Source/core/editing/CompositeEditCommand.cpp

 /*
  * Copyright (C) 2005, 2006, 2007, 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 350 matching lines @@
 
 void CompositeEditCommand::appendNode(PassRefPtrWillBeRawPtr<Node> node, PassRefPtrWillBeRawPtr<ContainerNode> parent)
 {
     ASSERT(canHaveChildrenForEditing(parent.get()));
     applyCommandToComposite(AppendNodeCommand::create(parent, node));
 }
 
 void CompositeEditCommand::removeChildrenInRange(PassRefPtrWillBeRawPtr<Node> node, unsigned from, unsigned to)
 {
     WillBeHeapVector<RefPtrWillBeMember<Node> > children;
-    Node* child = node->traverseToChildAt(from);
+    Node* child = NodeTraversal::childAt(*node, from);
     for (unsigned i = from; child && i < to; i++, child = child->nextSibling())
         children.append(child);
 
     size_t size = children.size();
     for (size_t i = 0; i < size; ++i)
         removeNode(children[i].release());
 }
 
 void CompositeEditCommand::removeNode(PassRefPtrWillBeRawPtr<Node> node, ShouldAssumeContentIsAlwaysEditable shouldAssumeContentIsAlwaysEditable)
 {
@@ skipping 1117 matching lines @@
 }
 
 void CompositeEditCommand::trace(Visitor* visitor)
 {
     visitor->trace(m_commands);
     visitor->trace(m_composition);
     EditCommand::trace(visitor);
 }
 
 } // namespace blink