Add GrVkTexelBuffer class

Bug: skia:
Change-Id: I6111902f58df3af92702d974a52d9c7f267634d4
Reviewed-on: https://skia-review.googlesource.com/15628
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
11 files changed