converted GrMagnifierEffect to SkSL

Bug: skia:
Change-Id: I6dc14ac66d5b911117e71fa23fef49a897082781
Reviewed-on: https://skia-review.googlesource.com/71342
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/gn/gpu.gni b/gn/gpu.gni
index ca5a919..87e3d9b 100644
--- a/gn/gpu.gni
+++ b/gn/gpu.gni
@@ -349,10 +349,12 @@
   "$_src/gpu/effects/GrEllipseEffect.h",
   "$_src/gpu/effects/GrGaussianConvolutionFragmentProcessor.cpp",
   "$_src/gpu/effects/GrGaussianConvolutionFragmentProcessor.h",
-  "$_src/gpu/effects/GrMatrixConvolutionEffect.cpp",
-  "$_src/gpu/effects/GrMatrixConvolutionEffect.h",
   "$_src/gpu/effects/GrLumaColorFilterEffect.cpp",
   "$_src/gpu/effects/GrLumaColorFilterEffect.h",
+  "$_src/gpu/effects/GrMagnifierEffect.cpp",
+  "$_src/gpu/effects/GrMagnifierEffect.h",
+  "$_src/gpu/effects/GrMatrixConvolutionEffect.cpp",
+  "$_src/gpu/effects/GrMatrixConvolutionEffect.h",
   "$_src/gpu/effects/GrNonlinearColorSpaceXformEffect.cpp",
   "$_src/gpu/effects/GrNonlinearColorSpaceXformEffect.h",
   "$_src/gpu/effects/GrOverdrawFragmentProcessor.cpp",