Bug 146352 support cancel execution for "view report ..." tool bar and menu actions.
Current "view report as HTML" and "view report as PDF" in the menu tool bar uses RunAndRender task to stream back the report output. As a result, total page count is not available when the report is being streamed back. Please change these two requests to use Run task and then render task to generate HTML or PDF, so that the total page count is calculate. preview tab could continue to use RunAndRender task, since it is for preview.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/service/ReportEngineService.java
*/
	public void clearCache( DataSetHandle dataSet ) throws BirtException
	{
		DataSessionContext context = new DataSessionContext(
				DataSessionContext.MODE_DIRECT_PRESENTATION, dataSet
						.getModuleHandle( ), null );
		DataRequestSession requestSession = DataRequestSession
				.newSession( context );
		IModelAdapter modelAdaptor = requestSession.getModelAdaptor( );
		DataSourceHandle dataSource = dataSet.getDataSource( );
		IBaseDataSourceDesign sourceDesign = modelAdaptor
				.adaptDataSource( dataSource );
		IBaseDataSetDesign dataSetDesign = modelAdaptor.adaptDataSet( dataSet );
		requestSession.clearCache( sourceDesign, dataSetDesign );
	}
	/**
	 * @param maxRows
	 */
	public void setMaxRows( int maxRows )
	{
		if ( config != null )
		{
			config.setMaxRowsPerQuery( maxRows );
		}
	}
	/**
	 * Collects all the distinct values for the given element and
	 * bindColumnName. This method will traverse the design tree for the given
	 * element and get the nearest binding column holder of it. The nearest
	 * binding column holder must be a list or table item, and it defines a