Bug 194549 Memory leak in chart device renderers
After memory analysis for Chart code, it indicates java.awt.Font objects are not garbage collected. Investigating the renderer code, Graphics2D objects in IDisplayServer and IDeviceRenderer are not disposed after chart rendering finished. Need to invoke IDeviceRenderer.dispose() after ChartReportItemPresentationImpl being finished, and dispose all required resources in that method, including IDisplayServer and anything else.
chart/org.eclipse.birt.chart.reportitem/src/org/eclipse/birt/chart/reportitem/ChartReportItemPresentationImpl.java
ReportItemPresentationBase
{
	private InputStream fis = null;
	private String imageMap = null;
	private String sExtension = null;
	private String sSupportedFormats = null;
	private String outputFormat = null;
	private Chart cm = null;
	private IDeviceRenderer idr = null;
	private ExtendedItemHandle handle;
	private RunTimeContext rtc = null;
	private List registeredDevices = null;
	private static ILogger logger = Logger.getLogger( "org.eclipse.birt.chart.reportitem/trace" ); 
	/**
	 * The constructor.
	 */
	public ChartReportItemPresentationImpl( )
	{
		registeredDevices = new ArrayList( );
		try
		{
			String[][] formats = PluginSettings.instance( )
					.getRegisteredOutputFormats( );
			for ( int i = 0; i < formats.length; i++ )