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>
diff --git a/gn/sksl.gni b/gn/sksl.gni
index 5eef5b1..ca6abcf 100644
--- a/gn/sksl.gni
+++ b/gn/sksl.gni
@@ -34,6 +34,7 @@
   "$_src/gpu/effects/GrConfigConversionEffect.fp",
   "$_src/gpu/effects/GrDitherEffect.fp",
   "$_src/gpu/effects/GrEllipseEffect.fp",
+  "$_src/gpu/effects/GrLumaColorFilterEffect.fp",
   "$_src/gpu/effects/GrRectBlurEffect.fp",
   "$_src/gpu/effects/GrOverdrawFragmentProcessor.fp",
   "$_src/gpu/effects/GrSimpleTextureEffect.fp",