ccpr: Generalize GrCCAtlas to work for cached atlases as well

Converts atlas offsets to SkIVector, adds a GrCCAtlasStack class,
moves the Op that renders the atlases into GrCCPerFlushResources, etc.

Bug: skia:
Change-Id: I5110be8e74da709f3ce84bb6798ead572142d0fa
Reviewed-on: https://skia-review.googlesource.com/134701
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
15 files changed