ccpr: Implement path mask caching

Implement caching as follows:

1) Instead of deleting the mainline ccpr atlas when finished, stash it
   away from flush to flush.

2) On subsequent flushes, check the stashed atlas to see if we can
   reuse any of its cachable paths. Copy reusable paths into 8-bit
   literal coverage atlases and store them in the resource cache.

3) Recycle the stashed atlas texture for the remaining paths in the
   flush.

Bug: skia:
Change-Id: I9b20fbea708646df1df3a5f9c044e2299706b989
Reviewed-on: https://skia-review.googlesource.com/134703
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>

0 files changed, 0 insertions, 0 deletions