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/adapter/ExpressionUtil.java
{
	private String columnName;
	private IBaseExpression expression;
	ColumnBinding( String name, IBaseExpression expression )
	{
		this.columnName = name;
		this.expression = expression;
	}
	ColumnBinding( String name, String expression, String groupName )
	{
		this.columnName = name;
		this.expression = new ScriptExpression( expression );
		if( groupName != null )
			this.expression.setGroupName( groupName );
	}
	
	public String getResultSetColumnName( )
	{
		return this.columnName;
	}
	public IBaseExpression getBoundExpression( )
	{
		return this.expression;
	}
}