Another attempt to fix TSAN

Change-Id: I1d6aebcd679a406a13911f4b91f72f4198fc8dc1
Reviewed-on: https://skia-review.googlesource.com/49461
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
1 file changed