firefox: add option to use fx_cast_bridge

pkgs/applications/networking/browsers/firefox/wrapper.nix

@@ -8,6 +8,7 @@
 , google_talk_plugin, fribid, gnome3/*.gnome-shell*/
 , browserpass, chrome-gnome-shell, uget-integrator, plasma-browser-integration, bukubrow
 , tridactyl-native
+, fx_cast_bridge
 , udev
 , kerberos
 }:
@@ -70,6 +71,7 @@ let
           ++ lib.optional (cfg.enableGnomeExtensions or false) chrome-gnome-shell
           ++ lib.optional (cfg.enableUgetIntegrator or false) uget-integrator
           ++ lib.optional (cfg.enablePlasmaBrowserIntegration or false) plasma-browser-integration
+          ++ lib.optional (cfg.enableFXCastBridge or false) fx_cast_bridge
           ++ extraNativeMessagingHosts
         );
       libs =   lib.optional stdenv.isLinux udev