diff --git a/editor/libeditor/base/nsIEditorSupport.h b/editor/libeditor/base/nsIEditorSupport.h
deleted file mode 100644
index ada2b0b872a..00000000000
--- a/editor/libeditor/base/nsIEditorSupport.h
+++ /dev/null
@@ -1,62 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef nsIEditorSupport_h__
-#define nsIEditorSupport_h__
-#include "nsISupports.h"
-
-class nsIDOMNode;
-
-/*
-Private Editor interface for a class that can provide helper functions
-*/
-
-#define NS_IEDITORSUPPORT_IID \
-{/* c4cbcda8-58ec-4f03-9c99-5e46b6828b7a*/ \
-0xc4cbcda8, 0x58ec, 0x4f03, \
-{0x0c, 0x99, 0x5e, 0x46, 0xb6, 0x82, 0x8b, 0x7a} }
-
-
-/**
- */
-class nsIEditorSupport  : public nsISupports {
-
-public:
-
-  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IEDITORSUPPORT_IID)
-
-  /** 
-   * SplitNode() creates a new node identical to an existing node, and split the contents between the two nodes
-   * @param aExistingRightNode   the node to split.  It will become the new node's next sibling.
-   * @param aOffset              the offset of aExistingRightNode's content|children to do the split at
-   * @param aNewLeftNode         [OUT] the new node resulting from the split, becomes aExistingRightNode's previous sibling.
-   * @param aParent              the parent of aExistingRightNode
-   */
-  NS_IMETHOD SplitNodeImpl(nsIDOMNode * aExistingRightNode,
-                           PRInt32      aOffset,
-                           nsIDOMNode * aNewLeftNode,
-                           nsIDOMNode * aParent)=0;
-
-  /** 
-   * JoinNodes() takes 2 nodes and merge their content|children.
-   * @param aNodeToKeep   The node that will remain after the join.
-   * @param aNodeToJoin   The node that will be joined with aNodeToKeep.
-   *                      There is no requirement that the two nodes be of the same type.
-   * @param aParent       The parent of aExistingRightNode
-   * @param aNodeToKeepIsFirst  if true, the contents|children of aNodeToKeep come before the
-   *                            contents|children of aNodeToJoin, otherwise their positions are switched.
-   */
-  NS_IMETHOD JoinNodesImpl(nsIDOMNode *aNodeToKeep,
-                           nsIDOMNode  *aNodeToJoin,
-                           nsIDOMNode  *aParent,
-                           bool         aNodeToKeepIsFirst)=0;
-
-  static PRInt32 GetChildOffset(nsIDOMNode* aChild, nsIDOMNode* aParent);
-};
-
-NS_DEFINE_STATIC_IID_ACCESSOR(nsIEditorSupport, NS_IEDITORSUPPORT_IID)
-
-#endif //nsIEditorSupport_h__
-