Most of the time, compositors just display the surface's current buffer
on an output. Add an helper to make it easy to support presentation-time
in this case.
The wlr_presentation_feedback struct now tracks presentation feedback
for multiple resources (but still a single surface content update). This
allows the compositor to properly send presentation events even when
there is more than one frame of latency or when it references a
surface's buffer.
Simon Ser
Ivan Molodetskikh