Fix image_from_yuv_textures with --preAbandonContext

Change-Id: Ibb2dfdf6eccb48fbd2c4a503e473170389e2ec2a
Reviewed-on: https://skia-review.googlesource.com/155169
Auto-Submit: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
1 file changed