xwayland: Do not queue frame callbacks unconditionally
The removed comment is not longer true: XWayland schedules its VSYNC from frame callbacks nowadays. Only sending callbacks when the surface actor is unobscured makes XWayland throttle its VSYNC to 1/sec, reducing repaints in many cases.
Follow up of !918 (merged)
Note: While this is not expected to regress XWayland client behaviour, if it does we should fix that in XWayland. Wayland compositors should not be expected to send frame callbacks if not appropriate.
How to test:
- apply https://gitlab.freedesktop.org/xorg/xserver/merge_requests/356 to XWayland
- open a terminal
- run
glxgears - hide
glxgearsbehind the terminal
Expected result:
- frames should drop to 1/sec
Edited by Robert Mader