Bug 89031 [Undo/Redo] IWorkbench#getOperationSupport() marked experimental
IWorkbench#getOperationSupport() marked experimental
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/IOperationApprover.java
IStatus proceedRedoing(IUndoableOperation operation,
			IOperationHistory history, IAdaptable info);
	/**
	 * Return a status indicating whether the specified operation should be
	 * undone. Any status that does not have severity <code>IStatus.OK</code>
	 * will not be approved. Implementers should not assume that the undo will
	 * be performed when the status is <code>OK</code>, since other operation
	 * approvers can veto the undo.
	 * 
	 * @param operation -
	 *            the operation to be undone
	 * @param history -
	 *            the history undoing the operation
	 * @param info -
	 *            the IAdaptable (or <code>null</code>) provided by the caller
	 *            containing additional information.  When this API is called
	 *            from the UI, callers can use this to provide additional info
	 *            for prompting the user.   If an IAdaptable is provided, 
	 *            callers are encourated to provide an adapter for the
	 *            org.eclipse.swt.widgets.Shell.class.
	 * @return the IStatus describing whether the operation is approved. The
	 *         undo will not proceed if the status severity is not
	 *         <code>OK</code>, and the caller requesting the undo will be
	 *         returned the status that caused the rejection. Any other status
	 *         severities will not be interpreted by the history.
	 */
	IStatus proceedUndoing(IUndoableOperation operation,
			IOperationHistory history, IAdaptable info);
}