Re: [mediacapture-screen-share] Specify track.label (#128)

Seems clear to me [in context](https://w3c.github.io/mediacapture-screen-share/#dom-mediadevices-getdisplaymedia): *"The provided media MUST include precisely one track of each media type in requestedMediaTypes. The devices chosen MUST be the ones determined by the user. Once selected, the source of a MediaStreamTrack MUST NOT change."*

It says once a user has picked a source, the user agent cannot pick a different source.

E.g. if a user picks "PowerPoint", the user agent is not allowed to change it to "My Calendar" or "Entire Desktop" later. This may seem obvious, but specs need to spell out the obvious.

It doesn't matter what the choices are. This goes to user trust:

If, given tabs A, B, and a well-explained "Follow active tab" device C, a user chooses C, I see no conflict in the model, provided C is always C, even if it sometimes looks like B. 

> letting the application handle device selection logic was a mistake

We're in screen-capture where we didn't! But there are three parties involved:
 1. application
 2. user agent
 3. user

This spec is super clear only the user (3) chooses.

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Received on Monday, 16 December 2019 19:13:10 UTC