Bug 190207 Integrate Aggregation builder with charts
Charts should be able to use aggregates in their databinding definition. The UI is missing the "Add Aggregation..." button in the chart databinding dialog.
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/ReportDataServiceProvider.java
for ( int i = 0; i < names.length; i++ )
		{
			names[i] = ( (DataSetHandle) list.get( i ) ).getQualifiedName( );
		}
		return names;
	}
	public final String[] getPreviewHeader( ) throws ChartException
	{
		Iterator iterator = getColumnDataBindings( itemHandle );
		ArrayList list = new ArrayList( );
		while ( iterator.hasNext( ) )
		{
			list.add( ( (ComputedColumnHandle) iterator.next( ) ).getName( ) );
		}
		return (String[]) list.toArray( new String[list.size( )] );
	}
	public final List getPreviewData( ) throws ChartException
	{
		return getPreviewRowData( getPreviewHeader( true ), -1, true );
	}
	private String[] getPreviewHeader( boolean isExpression )
			throws ChartException
	{
		String[] exps = getPreviewHeader( );
		if ( isExpression )
		{
			for ( int i = 0; i < exps.length; i++ )
			{
				exps[i] = ChartUIUtil.getExpressionString( exps[i] );
			}