Fix bug in op chaining

I created this problem with my fix to crbug.com/1108475

Bug: 1112259

Change-Id: Ieb001fa61bd9ed68dcae43e7d511b4581f16ef0f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/308638
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
5 files changed