scene_output: record and report timings

Merged Rose Hudson requested to merge rosefromthedead/wlroots:measurement into master

The pre-render time turns out to only be a couple of tens of microseconds on my slow test machine with a few weston-terminals open.

Not sure if it's a problem that the timer stops so early in the direct scanout case - i.e. it stops when wlr_scene_output_build_state returns, not when commit happens.

Edited by Rose Hudson

Merge request reports