use Make instead of Create to return a shared shader

samplecode/Sample2PtRadial.cpp

Index: samplecode/Sample2PtRadial.cpp
diff --git a/samplecode/Sample2PtRadial.cpp b/samplecode/Sample2PtRadial.cpp
index 07efd0a41c78a3d88500d26ed972a159a973f50f..c32025e9cbd94b47ca6f60515fd4f82b2c241781 100644
--- a/samplecode/Sample2PtRadial.cpp
+++ b/samplecode/Sample2PtRadial.cpp
@@ -33,12 +33,10 @@ protected:
         SkScalar r0 = 100;
         SkPoint c1 = { 100, 100 };
         SkScalar r1 = 100;
-        SkShader* s = SkGradientShader::CreateTwoPointConical(c0, r0, c1, r1, colors,
-                                                             nullptr, 2,
-                                                             SkShader::kClamp_TileMode);
-
         SkPaint paint;
-        paint.setShader(s)->unref();
+        paint.setShader(SkGradientShader::MakeTwoPointConical(c0, r0, c1, r1, colors,
+                                                             nullptr, 2,
+                                                             SkShader::kClamp_TileMode));
         canvas->drawPaint(paint);
     }