[graphite] Add Caps getters for default TextureInfos

Bug: skia:12466
Change-Id: I9165e5f49e4b897f4b315662221b944e362b7b41
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/456456
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
7 files changed