converted EllipseEffect to sksl

Bug: skia:
Change-Id: Id089b9ead7a21e903b001006dffff2381efd4ba3
Reviewed-on: https://skia-review.googlesource.com/23582
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
diff --git a/gn/sksl.gni b/gn/sksl.gni
index c447a7b..a349d9b 100644
--- a/gn/sksl.gni
+++ b/gn/sksl.gni
@@ -28,5 +28,6 @@
   "$_src/effects/GrCircleBlurFragmentProcessor.fp",
   "$_src/gpu/effects/GrCircleEffect.fp",
   "$_src/gpu/effects/GrDitherEffect.fp",
+  "$_src/gpu/effects/GrEllipseEffect.fp",
   "$_src/gpu/effects/GrSimpleTextureEffect.fp",
 ]