Note relationship to requirements of Screen Capture

[foolip]

https://w3c.github.io/mediacapture-screen-share/#dom-mediadevices-getdisplaymedia says:

The user agent MUST let the end-user choose which display surface to share out of all available choices every time, and MUST NOT use constraints to limit that choice. Instead, constraints MUST be applied to the media chosen by the user, only after they have made their selection. This prevents an application from influencing the selection of sources, see § 5.3 Unconstrained Display Surface Selection for details.

While preferCurrentTab won't limit which display surfaces are possible to chose, it will influence which surface is easiest to chose.

In a literal reading I don't think there's a willful violation (which would be OK but not great) but it is still worth a note explaining how this fits together. Maybe link back to that spec and affirm that the requirement to not use constraints still applied, but that an influence of UI order is happening.

[alvestrand]

A relevant open issue on w3c/mediacapture-screen-share#184

There's not consensus among participants that the absolute ban on influencing user choice was a rational and defensible decision.

[foolip]

Thanks for linking! If the WG / editors can't agree on a change for https://w3c.github.io/mediacapture-screen-share/ and it seems like preferCurrentTab requires ignoring some of its normative requirements, then a willful violation in https://wicg.github.io/prefer-current-tab/ would be the clearest way to deal with it I think.