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.device.swt/src/org/eclipse/birt/chart/device/swt/SwtTextRenderer.java
{
	private static final PaletteData PALETTE_DATA = new PaletteData( 0xFF0000,
			0xFF00,
			0xFF );
	private static final int TRANSPARENT_COLOR = 0x123456;
	private static final int SHADOW_THICKNESS = 3;
	private SwtDisplayServer _sxs = null;
	/**
	 * The constructor.
	 */
	SwtTextRenderer( SwtDisplayServer sxs )
	{
		_sxs = sxs;
	}
	/**
	 * This method renders the 'shadow' at an offset from the text 'rotated
	 * rectangle' subsequently rendered.
	 * 
	 * @param ipr
	 * @param iLabelPosition
	 *            The position of the label w.r.t. the location specified by
	 *            'lo'
	 * @param lo
	 *            The location (specified as a 2d point) where the text is to be