Bug 210716 Support switch Text/Chart view in crosstab cell
Need crosstab UI provide support to switch between Text and Chart view in measure/aggregation cell.
xtab/org.eclipse.birt.report.item.crosstab.core/src/org/eclipse/birt/report/item/crosstab/core/de/internal/CrosstabModelUtil.java
* @param elements
	 * @return
	 */
	public static List getReportItems( List elements )
	{
		if ( elements == null || elements.isEmpty( ) )
			return Collections.EMPTY_LIST;
		List values = new ArrayList( );
		for ( int i = 0; i < elements.size( ); i++ )
		{
			if ( elements.get( i ) instanceof DesignElementHandle )
				values.add( CrosstabUtil.getReportItem( (DesignElementHandle) elements.get( i ) ) );
		}
		return values;
	}
	/**
	 * Gets the opposite axis type for the given axis. If axis type is column,
	 * then return row; if axis type is row, then return column; otherwise
	 * return <code>ICrosstabConstants.NO_AXIS_TYPE</code>.
	 * 
	 * @param axisType
	 * @return
	 */
	public static int getOppositeAxisType( int axisType )
	{
		switch ( axisType )
		{
			case COLUMN_AXIS_TYPE :
				return ROW_AXIS_TYPE;
			case ROW_AXIS_TYPE :