Filter transformed atlas images correctly on GPU.

The GPU backend was not considering the SkRSXform when optimizing the
filter mode. This would cause rotated or scaled atlas images to look
pixelated, regardless of the paint filter.

Change-Id: I65f4bee6351e10349114869b823b2114bbcf70be
Bug: skia:10662
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/313081
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
7 files changed