Add SkImage_Gpu::MakePromiseYUVATexture

This is pulled out of:

https://skia-review.googlesource.com/c/skia/+/151983 (Test YUV images in DDL)

Bug: skia:7903
Change-Id: Ie6710439d4d922da8d4a41df83d12149c144fc81
Reviewed-on: https://skia-review.googlesource.com/156761
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
3 files changed