--- a/editor/libeditor/EditorBase.cpp
+++ b/editor/libeditor/EditorBase.cpp
@@ -823,32 +823,16 @@ EditorBase::EnableUndo(bool aEnable)
   }
   DebugOnly<bool> disabledUndoRedo = DisableUndoRedo();
   NS_WARNING_ASSERTION(disabledUndoRedo,
     "Failed to disable undo/redo transactions");
   return NS_OK;
 }
 
 NS_IMETHODIMP
-EditorBase::GetNumberOfUndoItems(int32_t* aNumItems)
-{
-  *aNumItems = static_cast<int32_t>(NumberOfUndoItems());
-  MOZ_ASSERT(*aNumItems >= 0);
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-EditorBase::GetNumberOfRedoItems(int32_t* aNumItems)
-{
-  *aNumItems = static_cast<int32_t>(NumberOfRedoItems());
-  MOZ_ASSERT(*aNumItems >= 0);
-  return NS_OK;
-}
-
-NS_IMETHODIMP
 EditorBase::GetTransactionManager(nsITransactionManager** aTransactionManager)
 {
   if (NS_WARN_IF(!aTransactionManager)) {
     return NS_ERROR_INVALID_ARG;
   }
   if (NS_WARN_IF(!mTransactionManager)) {
     return NS_ERROR_FAILURE;
   }

--- a/editor/nsIEditor.idl
+++ b/editor/nsIEditor.idl
@@ -164,26 +164,16 @@ interface nsIEditor  : nsISupports
     *                 if PR_FALSE the undo system is turned off if it
     *                 was previously on
     * @return         if aEnable is PR_TRUE, returns NS_OK if
     *                 the undo system could be initialized properly
     *                 if aEnable is PR_FALSE, returns NS_OK.
     */
   void enableUndo(in boolean enable);
 
-  /**
-   * The number of items on the undo stack.
-   */
-  readonly attribute long numberOfUndoItems;
-
-  /**
-   * The number of items on the redo stack.
-   */
-  readonly attribute long numberOfRedoItems;
-
   /** undo reverses the effects of the last Do operation,
     * if Undo is enabled in the editor.
     * It is provided here so clients need no knowledge of whether
     * the editor has a transaction manager or not.
     * If a transaction manager is present, it is told to undo,
     * and the result of that undo is returned.
     * Otherwise, the Undo request is ignored and an
     * error NS_ERROR_NOT_AVAILABLE is returned.