Bug 143890 [Smoke]Chart cann't preview as web view
Details: [Smoke]Chart cann't preview as web view Setp: 1.Add a chart on report design. 2.Preview as web view. Actual result: The chart can't be preview on web view.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/service/ReportEngineService.java
String[] columnNames = new String[columns.size( )];
		Iterator iSelectedColumns = columns.iterator( );
		for ( int i = 0; iSelectedColumns.hasNext( ); i++ )
		{
			columnNames[i] = (String) iSelectedColumns.next( );
		}
		IDataExtractionTask dataTask = null;
		IExtractionResults result = null;
		IDataIterator iData = null;
		try
		{
			synchronized ( this.getClass( ) )
			{
				dataTask = engine.createDataExtractionTask( document );
			}
			dataTask.selectResultSet( resultSetName );
			dataTask.selectColumns( columnNames );
			dataTask.setLocale( locale );
			result = dataTask.extract( );
			if ( result != null )
			{
				iData = result.nextResultIterator( );
				if ( iData != null && columnNames.length > 0 )
				{
					StringBuffer buf = new StringBuffer( );
					
					buf.append( columnNames[0] );
					for ( int i = 1; i < columnNames.length; i++ )
					{
						buf.append( ',' );