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
* @param index
		 *            The projected column index.
		 * @return The label of the specified column.
		 * @throws BirtException
		 *             if given index is invalid.
		 */
		public String getColumnLabel( int index ) throws BirtException
		{
			return null;
		}
		/**
		 * Indicates whether the specified projected column is defined as a
		 * computed column. A computed column is one that is not retrieved from
		 * the underlying data provider. Only those computed columns declared
		 * explicitly in a data set design are considered as "computed" columns.
		 * 
		 * @param index
		 *            The projected column index.
		 * @return true if the given column is a computed column; false
		 *         otherwise.
		 * @throws BirtException
		 *             if given index is invalid.
		 */
		public boolean isComputedColumn( int index ) throws BirtException
		{
			return false;
		}
	}
}