This is a small change to show that ffmpeg is a supported browser parameter
value in the script usage. Although, the whole file should probably be
refactored now to something more generic like roll_download.js since ffmpeg
is just reusing the logic and isn't a browser.
We now commit protocol.ts files during the roll.
New utils/roll_browser.js helps with that.
This makes our installation very shallow:
- build installer;
- download browsers.