ccpr: Cache paths with >=50% visibility

Adds a hit count to cache entries. Paths now don't get stashed until
their second hit (and cached on their third). Mostly-visible, cachable
paths render their entire mask on the second hit, in hopes that we
will be able to cache them alongside the fully visible ones.

Bug: skia:
Change-Id: Idd18f5dc3090f13531f630d229f4808198695fea
Reviewed-on: https://skia-review.googlesource.com/136541
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
5 files changed