Bug 209119 Need WebViewer provide cancel function
Need WebViewer provide a cancel function, this will be used to cancel current report execution during designer preview.
viewer/org.eclipse.birt.report.viewer/src/org/eclipse/birt/report/viewer/utilities/WebViewer.java
*            report report
	 * @param format
	 *            report format
	 * @param browser
	 *            SWT browser instance
	 * @deprecated
	 */
	public static void display( String report, String format, Browser browser )
	{
		startWebApp( );
		browser
				.setUrl( createURL(
						"run", report, format, true, null, null, null ) + "&" + new Random( ).nextInt( ) ); 
	}
	/**
	 * Displays the specified url using eclipse SWT browser.
	 * 
	 * @param report
	 *            report report
	 * @param format
	 *            report format
	 * @param browser
	 *            SWT browser instance
	 * @param servletName
	 *            servlet name to viewer report
	 */
	public static void display( String report, String format, Browser browser,
			String servletName )
	{
		startWebApp( );