Code review comment for lp:~dandrader/unity8/drag-crash-1228336

This looks really good. The crashes are definitely gone.

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can we const & all occurances of "SharedTimeSource timeSource" in method arguments?

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715 + // Estimate of the maximum number of active touches we might reach.
716 + // Not a problem if it ends up being an underestimate as this is just
717 + // an optimization.
718 + reserve(10);

If it's just an optimization, shouldn't we rather go for 3 or something that is more realistic? I think it happens max once a year that I touch the screen with all 10 fingers.