Add tonal color support for shadows.

Bug: skia:
Change-Id: Ib9bd9083da1d8a9fa90ae7c710386e6903541fd5
Reviewed-on: https://skia-review.googlesource.com/18148
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
diff --git a/gn/samples.gni b/gn/samples.gni
index 4a50313..80e0663 100644
--- a/gn/samples.gni
+++ b/gn/samples.gni
@@ -81,6 +81,7 @@
   "$_samplecode/SampleRepeatTile.cpp",
   "$_samplecode/SampleShaders.cpp",
   "$_samplecode/SampleShaderText.cpp",
+  "$_samplecode/SampleShadowColor.cpp",
   "$_samplecode/SampleShadowReference.cpp",
   "$_samplecode/SampleShadowUtils.cpp",
   "$_samplecode/SampleShip.cpp",