Bug 121687 Exception throws when export data in table which inside a grid cell.
Description: Exception throws when export data in table which inside a grid cell. Steps to reproduce: 1. insert a grid. 2. insert one table to one grid cell. 3. insert another table to the other grid cell. 4. export data in two tables. Expected result: Data are exported. Actual result: Exception in: ReportEngineService.getMetaData( )
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/parser/EngineIRVisitor.java
{
			textItem.setTextType( contentType );
		}
		textItem.setText( handle.getContentKey( ), handle.getContent( ) );
		currentElement = textItem;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.api.DesignVisitor#visitExtendedItem(org.eclipse.birt.report.model.api.ExtendedItemHandle)
	 */
	protected void visitExtendedItem( ExtendedItemHandle obj )
	{
		ExtendedItemDesign extendedItem = new ExtendedItemDesign( );
		setupReportItem( extendedItem, obj );
		currentElement = extendedItem;
	}
	protected void setupGroup( GroupDesign group, GroupHandle handle )
	{
		
		group.setName( handle.getName( ) );
		
		group.setOnStart( handle.getOnFinish( ) );
		
		group.setOnRow( handle.getOnRow( ) );
		
		group.setOnFinish( handle.getOnFinish( ) );
	}
	/**
	 * create a table band using the items in slot.