Use mipmapping/protected to lookup scratch textures.

Include protected in scratch key.

Change-Id: I0dfc58c9f54e8279a39adf4bad808b7e0e72cba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/241397
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
7 files changed