>> The xdg-shell thing has been integrated upstream, and the demos seem to
>> no longer exist.

Actually, is this true?  Looking through the sommelier git log[1] I see
32050c0ea6c00c16999915856b40a6a6b8b41bb9:

> Revert "vm_tools: sommelier: Switch to the stable version of xdg-shell"
>
> This reverts commit be4e16feb380360cabbb5d6199a09592ecaf4a42.
>
> Reason for revert: Breaks the version of gtk3 shipped with stretch

[1]: https://chromium.googlesource.com/chromiumos/platform2/+log/refs/heads/main/vm_tools/sommelier

The relevant Chromium bugs[2][3] are:

Issue 1022716: Sommelier does not support the stable xdg-shell
Issue 1120277: GTK3 broken on stretch in M86

[2]: https://bugs.chromium.org/p/chromium/issues/detail?id=1022716
[3]: https://bugs.chromium.org/p/chromium/issues/detail?id=1120277

It doesn't look like it's been reintroduced since, and there's no
further activity on the bug, so I think current Sommelier doesn't
support stable xdg-shell after all.

From what I can tell, they backed out stable xdg-shell because their
Debian version is too old to support it.  So we probably still need this
patch.  It doesn't still apply cleanly, though.  It would probably be
better to just revert their revert than to keep carrying around Puck's
version so that we're closer to upstream while still supporting stable
xdg-shell.

Also CCing Thomas, with whom I've previously talked about stable
xdg-shell in Sommelier, in case he hasn't seen that it was reverted
upstream.