Bug 1700151 - Detach subsurfaces on hide, r=gw
Bug 1700151 - Detach subsurfaces on hide, r=gw

Detach subsurfaces when hiding by removing the subsurface object.
This allows us to reattach the subsurface to another parent surface,
i.e. another window, and/or recycle the subsurface within a surface pool.

Recycling subsurfaces is until now a quite rare thing in the Wayland
world. Thus adding it to the example-compositor allows to stress-
test Wayland compositors.

Depends on D110745

Differential Revision: https://phabricator.services.mozilla.com/D110863

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/932d064c47d67c92aec553fe4e2f48f69fdd295d

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender