converted ConstColorProcessor to SkSL

Bug: skia:
Change-Id: Ic3b18f82c1ab940637fb26dec1cf376dd859b35d
Reviewed-on: https://skia-review.googlesource.com/73720
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
diff --git a/gn/sksl.gni b/gn/sksl.gni
index 3bc0a1d..e40da5d 100644
--- a/gn/sksl.gni
+++ b/gn/sksl.gni
@@ -33,6 +33,7 @@
   "$_src/gpu/effects/GrBlurredEdgeFragmentProcessor.fp",
   "$_src/gpu/effects/GrCircleEffect.fp",
   "$_src/gpu/effects/GrConfigConversionEffect.fp",
+  "$_src/gpu/effects/GrConstColorProcessor.fp",
   "$_src/gpu/effects/GrDitherEffect.fp",
   "$_src/gpu/effects/GrEllipseEffect.fp",
   "$_src/gpu/effects/GrLumaColorFilterEffect.fp",