Bug 123316 [Undo] - API BEHAVIOR - should always place a successfully undone/redone op on the redo/undo history
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/IOperationHistory.java
/**
	 * <p>
	 * Remove the specified operation approver from the list of operation
	 * approvers that are consulted before an operation is undone or redone.
	 * </p>
	 * 
	 * @param approver
	 *            the IOperationApprover to be removed. Must not be
	 *            <code>null</code>. If an attempt is made to remove an
	 *            instance which is not already registered with this instance,
	 *            this method has no effect.
	 */
	void removeOperationApprover(IOperationApprover approver);
	/**
	 * <p>
	 * Remove the specified listener from the list of operation history
	 * listeners.
	 * </p>
	 * 
	 * @param listener
	 *            The IOperationHistoryListener to be removed. Must not be
	 *            <code>null</code>. If an attempt is made to remove an
	 *            instance which is not already registered with this instance,
	 *            this method has no effect.
	 */
	void removeOperationHistoryListener(IOperationHistoryListener listener);
	/**
	 * <p>
	 * Replace the specified operation in the undo or redo history with the
	 * provided list of replacements. This protocol is typically used when a