ccpr: Set atlas proxy size to draw bounds rather than backing size

Bug: skia:
Change-Id: I6605754ecc5377b1c25847fdda478f8246979a2f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209808
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
8 files changed