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
ResultSetColumnHandle resultSetColumn = (ResultSetColumnHandle) iter.next( );
				ComputedColumn column = StructureFactory.newComputedColumn( handle,
						resultSetColumn.getColumnName( ) );
				column.setDataType( resultSetColumn.getDataType( ) );
				column.setExpression( DEUtil.getExpression( resultSetColumn ) );
				columnList.add( column );
			}
			return columnList;
		}
		return Collections.EMPTY_LIST;
	}
	/**
	 * Gets dataset from ReportItemHandle at first. If null, get dataset from
	 * its container.
	 * 
	 * @return direct dataset
	 */
	protected DataSetHandle getDataSetFromHandle( )
	{
		if ( itemHandle.getDataSet( ) != null )
		{
			return itemHandle.getDataSet( );
		}
		List datasetList = DEUtil.getDataSetList( itemHandle.getContainer( ) );
		if ( datasetList.size( ) > 0 )
		{
			return (DataSetHandle) datasetList.get( 0 );
		}
		return null;
	}