converted LumaColorFilterEffect to sksl

Bug: skia:
Change-Id: I208984ec9ad357249ee1b2fe28477f1450b4b69d
Reviewed-on: https://skia-review.googlesource.com/67848
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
9 files changed