Bug 182680 Use feature of new Aggregation framework of Data Engine.
DataEngine will implement new aggregation framework in 2.2.0RC0. After the implementation is finished Engine should go ahead to use new column bindings in definition of map/highlight.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/ResultMetaData.java
String name = (String) entry.getKey( );
			IBaseExpression expr = (IBaseExpression) entry.getValue( );
			int type = expr.getDataType( );
			metaEntries.add( new MetaDataEntry( name, type ) );
		}
	}
	public int getColumnCount( )
	{
		if ( selectedColumns != null )
		{
			return selectedColumns.length;
		}
		if( null != parentMetaData )
		{
			return parentMetaData.getColumnCount( );
		}
		return metaEntries.size( );
	}
	public String getColumnName( int index ) throws BirtException
	{
		index = getColumnIndex( index );
		if( null != parentMetaData )
		{
			return parentMetaData.getColumnName( index );
		}
		else
		{
			MetaDataEntry entry = (MetaDataEntry) metaEntries.get( index );
			return entry.name;
		}