Add wl shell protocol implementation

[lmaxyz]

Make available using wl shell protocol for windows creation.

Important

This implementation is only for make available to create windows in Sailfish OS by winit.
I don't know what else it is need for, because it's deprecated and xdg uses everywhere.

[i509VCB]

I'm not terribly interested in wl_shell support. But I guess someone needs it.

Although I'd ask if sailfish os already has xdg shell. If it does then I don't see much purpose beyond legacy support (which you did mention).

For winit you'll need to convince @kchibisov, just making a pull request here doesn't guarantee winit will use the wl_shell code here.

[lmaxyz]

As I know there is no xdg support in Sailfosh OS.

The next step is to contribute in winit, if this PR will be merged. Or you mean winit's maintainers may not approve implementation for deprecated protocol?

[kchibisov]

We explicitly dropped wl_shell because no one should really use it, it's dropped in mostly every compositor. I personally don't see a reason in using it at all at this point and rather like things to move to xdg_shell instead.

[lmaxyz]

I see. But compositor in Sailfish OS still uses wl_shell, so i decided to add its support to make available creating application using slint ui for this OS.
This OS also uses qt_extended_surface protocol to correctly close its applications and I'm also going to add implementation of this protocol to winit, despite it's deprecated too.

If it's a big problem to have this code in repository, I'll fork it. But I think it's not a big deal to implement it as feature, that will uses only if needs, and xdg will use by default.

[kchibisov]

I'm not interested in maintaining protocols no one can really test in winit. I'd suggest to update sailfish instead.

[lmaxyz]

And why do you think nobody can test these protocols?

I agree with your suggestion, but I only do what I can do, and Sailfish OS with its c++ code out of my opportunities, so I decided to add support for these protocols to winit until sailfish's maintainers updates compositor.

So, you won't accept PR for these protocols for winit, right?

[kchibisov]

I won't accept them for winit, since all mainline compositors don't support them anymore, meaning that average contributor can not test them, because they require special setups, etc.