Initial CL to create dummy GrShaderDataManager and thread it through

src/effects/gradients/SkTwoPointConicalGradient.h

Index: src/effects/gradients/SkTwoPointConicalGradient.h
diff --git a/src/effects/gradients/SkTwoPointConicalGradient.h b/src/effects/gradients/SkTwoPointConicalGradient.h
index 0a3cd902018b615a5c774d0b2cbd7cbc4aeecf8a..04b4fed5f54c4222f26848412b81292a3943a9e8 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient.h
+++ b/src/effects/gradients/SkTwoPointConicalGradient.h
@@ -63,7 +63,8 @@ public:
                                  TileMode* xy) const override;
     SkShader::GradientType asAGradient(GradientInfo* info) const  override;
     virtual bool asFragmentProcessor(GrContext*, const SkPaint&, const SkMatrix&, const SkMatrix*,
-                                     GrColor*, GrFragmentProcessor**) const override;
+                                     GrColor*, GrShaderDataManager*,
+                                     GrFragmentProcessor**) const override;
     bool isOpaque() const override;
 
     SkScalar getCenterX1() const { return SkPoint::Distance(fCenter1, fCenter2); }