Screensharing with PipeWire via XDG Desktop Portal requires explicit
user permission via permission dialogs. Chromium has separate tabs for
screens and windows and thus its portal implementation requests
permissions separately for each. However, the screencast portal has no
such limitation and supports both screens and windows in a single
request.
WebRTC now supports this type of capture in a new method called
called `CreateGenericCapturer`. The `desktopCapturer` implementation has
been modified to use it. Additionally, Chromium has been patched to use
same generic capturer to ensure that the source IDs remain valid for
`getUserMedia`.
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