Bug 148755 Add tthe status to the ActivityStackEvent.
If the the event rollback, the ActivityStackEvent status should be ROLL_BACK.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/activity/ActivityStack.java
*/
	public void setStackLimit( int limit )
	{
		assert limit >= 0;
		stackLimit = limit;
		trimUndoStack( );
	}
	/**
	 * Returns an array of the records in the order they were executed. This
	 * method is useful for debugging only, since the list contains no marker to
	 * note which records have been undone.
	 * 
	 * @return An array containing all records in the order they were executed.
	 */
	public Object[] getRecords( )
	{
		List records = new ArrayList( undoStack );
		for ( int i = redoStack.size( ) - 1; i >= 0; i-- )
		{
			records.add( redoStack.get( i ) );
		}
		return records.toArray( );
	}
	/**
	 * Peeks at the top of the redo stack.
	 * 
	 * @return The record at the top of the redo stack, or null if there is no
	 *         such record.
	 */
	public IActivityRecord getRedoRecord( )