Op_noop is pointless

We were using it as signal to skip a stage,
but a null argument pointer serves just as well.

Change-Id: I0bab2c5468c4fb9cd4dc3968d1ddd0520d84f892
Reviewed-on: https://skia-review.googlesource.com/152680
Auto-Submit: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed