Allow async read back GM to YUV to fail. Skip on DDL.

Currently fails on GrContext's that don't support transfer buffers.
TODO: fallback to synchronous read pixels.

Bug: skia:8962
Change-Id: I464ea00519013a371ba29912a0220fa42b252243
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/220299
Commit-Queue: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
Auto-Submit: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
1 file changed