If you are looking for a native option use [0] or [1] and you can send anything from ffmpeg to webrtc. ffmpeg itself doesn't support WebRTC so need to use something for the last part.
[0] https://github.com/rviscarra/webrtc-remote-screen
[1] https://github.com/pion/webrtc/tree/master/examples/rtp-to-w...