This is a reland of e7153012682ccd3d1eacc18f802cab7820e3bad3
Original change's description:
> Implemented screen enumeration and selection for desktop capture under X11 using the X Resize and Rotate entension version 1.5.
>
> Bug: chromium:396091
> Change-Id: Ia1b36c771632c536bb8d15322461b479fabc409e
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/148768
> Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
> Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#29083}
Bug: chromium:396091
Change-Id: I0d9171ae5f340e0489e4b45ce5d97bc52b0a4904
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/156067
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29655}