Allow passing in an existing MediaStream

[atav32]

Feature Request:

Re-rendering <ReactWebcam/> on Firefox will prompt the user for video permission several times. This is intentional behavior according to Mozilla, i.e. "keep the user in charge", mozilla/standards-positions#19 (comment).

To avoid annoying the user and to keep the media permission user experience in-line with other browsers, I'd like to manually make a getUserMedia() call, hold on to that MediaStream and then pass it into <ReactWebcam/>.

The alternative would be to contort the app to keep <ReactWebcam/>'s video element from being re-rendered (maybe putting it in a portal; hiding & unhiding it; etc).

[mozmorris]

@atav32 could you provide an example of this?

I have created a simple demo that updates a component at a 1 second interval. Tested in Firefox and I don't get asked for permission on each render. Perhaps I'm misunderstanding the problem so an example would be useful.

https://codepen.io/mozmorris/pen/KKgwZmo?editors=0010