Code review comment for lp:~vanvugt/mir/ddouble

Indeed I think I can shorten the new tests more and maintain robustness... They're not "time sensitive" like other tests though. The only timing I introduce is the sleep in throttled_compositor_thread() to ensure that the client loop (which is not throttled at all) runs faster than the compositor. That holds true even under load on a slow system so no false positives are expected (but the probability is never quite zero).

As for a "policy" interface. It's possible but would be messy, requiring more code (more classes) and end up less readable than "q.scaling_delay()" is right now. So I'd rather not.