Fix ducky_yuv_blend in preabandoned context mode

TBR:robertphillips@google.com

Change-Id: I605cff35d5559597aab9129ebc83b9df81cb62ee
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/306952
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
1 file changed