1701044 - Auto-select first item in WebRTC screen/window sharing menulist, and remove "Select screen or window" default item

Status: NEW

(Firefox :: Site Permissions, task, P2)

Comment 1

[Mike Conley (:mconley) (:⚙️)]

The separator below the "Select screen or window" item should also be removed, naturally.

Comment 2

[Paul Zühlcke [:pbz]]

Attachment: Bug 1701044 - Auto-select first item in WebRTC screen and window sharing menulist. r=jib,johannh

Comment 3

[Paul Zühlcke [:pbz]]

Not as simple as I initially thought. I'm running into some tests failures. For example: https://treeherder.mozilla.org/logviewer?job_id=335714009&repo=try&lineNumber=4627
I believe we run into a race condition after the async getUserMedia call for the screen share preview. This is more apparent now that we directly show the preview whenever the screen sharing permission prompt is shown. I'm looking into it.

Comment 4

[Paul Zühlcke [:pbz]]

In the review for the patch :jib brought up some concerns:
https://phabricator.services.mozilla.com/D110977#inline-633853

// "Select a Window or Screen" is the default because we can't and don't
// want to pick a 'default' window to share (Full screen is "scary").

This comment still seems true to me. We can't reasonably guess which source the user wishes to share, and presharing one risks miscommunicating that this is the source the web page is asking for.

There really is no good candidate for "default choice" for screen capture, since we don't know which window the user intends to share.

The only candidate that might have made sense as a default would be "Full screen", except it security issues, and the spec is admonishing us to steer users away from sharing their full screen for security reasons. See https://crbug.com/920752

What's driving this change?

I agree that we need to be careful about which screen or window we select by default here.

Tyler, could you explain what we want to achieve with this change?
Since we don't know which screen or window the user wants to share, is there even a benefit in pre-selecting the first one?

Comment 5

[Paul Zühlcke [:pbz]]

I'm assigning for now. Let me know if you still want to pursue this / feel free to pick it up.