Add support for wrapped GrAttachments.

Bug: skia:10828
Change-Id: Ifab9c2b179fa981a94d03ff96718c3b31f745fee
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/331338
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
2 files changed