Something

        case "print":          var aWindow = getMostRecentBrowserWindow();          var printerName = remoteParams[0];          var printService = Components.classes["@mozilla.org/gfx/printsettings-service;1"].getService(Components.interfaces.nsIPrintSettingsService);           var webBrowserPrint = aWindow.QueryInterface(Components.interfaces.nsIInterfaceRequestor).getInterface(Components.interfaces.nsIWebBrowserPrint);           var printSettings = printService.newPrintSettings;          printSettings.printSilent = true;          if (printerName && printerName != '') {            printSettings.printerName = printerName;          } else {            printSettings.printerName = printService.defaultPrinterName;          }          printService.initPrintSettingsFromPrinter(printSettings.printerName, printSettings);          try {            webBrowserPrint.print(printSettings, null);          }          catch (e) {            throw NS_ERROR_ABORT;          }          break;