Simplify GrMixerEffect.

The sample() keyword now allows null fragment processors to be passed
in, substituting the input color when this occurs. The ternary did the
same thing, so it no longer adds value.

Without the ternary, the expression becomes simple enough that it can
fit on a single line, so the temporary variables were removed as well.

Change-Id: I8d0ceb437791a87a4244576a180e8c4eec441f2b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/300644
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed