Making a sample for shadow maps for more intensive development

src/core/SkShadowShader.h

Index: src/core/SkShadowShader.h
diff --git a/src/core/SkShadowShader.h b/src/core/SkShadowShader.h
index 7cbcbca224ceb82a3b9627b45d626d610cc4a78d..163d58acd7638f444d6937e4b2402634b91d50bd 100644
--- a/src/core/SkShadowShader.h
+++ b/src/core/SkShadowShader.h
@@ -25,6 +25,10 @@ public:
                                 sk_sp<SkLights> lights,
                                 int diffuseWidth, int diffuseHeight);
 
+    // The shadow shader supports any number of ambient lights, but only
+    // 4 non-ambient lights (currently just refers to directional lights).
+    static constexpr int kMaxNonAmbientLights = 4;
+
     SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
 };