`Occluded` change must be synced with winit

[kchibisov]

State change on Wayland, demands confirmation in form of ack + commit, commit usually done when drawing, however when using Vsync extension drawing will block indefinitely when you'll have Occluded event.

To solve that winit must have a way to commit on-behalf of the users, however doing so unconditionally will break clients and may result in desyncs, but asking them to draw and then send Occluded is also not an option, thus Occluded itself should ask whether the user stopped their rendering/continued their rendering, thus on stop winit can do wl_surface::commit.

This issue is also kind of present with other state changes, and not really specific to occluded, however occluded is the only where it really matters.

Until it's resolved it winit will remove the handling of this event.

[mahkoh]

To solve that winit must have a way to commit on-behalf of the users

Reasonably sure that this is not possible because any WSI takes exclusive ownership of this. Only the WSI may call commit.

[kchibisov]

Reasonably sure that this is not possible because any WSI takes exclusive ownership of this. Only the WSI may call commit.

It's possible if you communicate correctly, wsi can not commit on its own either, you have to call into present function, and if you indicate such a change with a callback you can certainly do so on behalf of the user, because they indicated that they won't commit..