screen share repro

This is an Electron Fiddle to reproduce an issue with screen share in an Electron app.

1. Clone this branch
2. Load in Electron Fiddle
3. Run the Electron test
4. Join the call
5. Start screen share
6. Join the room in Daily Prebuilt and you will not be able to see the shared screen. If I stop the screen share and start it, it works.