Bug 199834 Enable access to IContent object in IReportItemPresentation layer
In IReportItemPresentation layer, the extended item may want to access properties from current IContent object, for example, bookmark, content style. So we need expose the content object in this layer.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/data/dte/QueryResultSet.java
public String getGroupId( int groupLevel )
	{
		return String.valueOf( groupLevel ) + "." + getRowId( groupLevel ); 
	}
	private String getRowId( int groupLevel )
	{
		assert rowIdOfGroups.length > 0;
		int level = groupLevel >= rowIdOfGroups.length
				? rowIdOfGroups.length - 1
				: groupLevel;
		level = groupLevel < 0 ? 0 : groupLevel;
		return String.valueOf( rowIdOfGroups[level] );
	}
	String baseRSetID;
	public void setBaseRSetID( String id )
	{
		baseRSetID = id;
	}
	public String getBaseRSetID( )
	{
		if ( baseRSetID == null && parent instanceof QueryResultSet )
		{
			return ( (QueryResultSet) parent ).getBaseRSetID( );
		}
		return baseRSetID;
	}
	public void close( )
	{