Code review comment for lp:~kdub/mir/nested-passthrough

(3) I wonder if there ever might be some future platform which can't pass-through non-bypassable buffers (abgr). Doesn't seem to be important yet but it wouldn't hurt us to remove all doubt and probe using xbgr only.

Cemil:
You won't get more accurate (or encouraging) performance numbers than my above measurements. Although sadly mirvanity only runs on desktop (no Video4Linux support on Android!?).