[graphite] Add basic Texture files.

Bug: skia:12466
Change-Id: If708d8a4bd00802e60a860215edcb64db179e573
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/454616
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
4 files changed