use Make instead of Create to return a shared shader

samplecode/SampleVertices.cpp

Index: samplecode/SampleVertices.cpp
diff --git a/samplecode/SampleVertices.cpp b/samplecode/SampleVertices.cpp
index 2f2dc024d0eea04e74467203ca4c15f9dc4358e6..a8dcd22bb3c06a9d6648abba6cf8cd5748a5c29b 100644
--- a/samplecode/SampleVertices.cpp
+++ b/samplecode/SampleVertices.cpp
@@ -25,7 +25,7 @@
 #include "SkOSFile.h"
 #include "SkStream.h"
 
-static SkShader* make_shader0(SkIPoint* size) {
+static sk_sp<SkShader> make_shader0(SkIPoint* size) {
     SkBitmap    bm;
     size->set(2, 2);
     SkPMColor color0 = SkPreMultiplyARGB(0x80, 0x80, 0xff, 0x80);
@@ -38,21 +38,20 @@ static SkShader* make_shader0(SkIPoint* size) {
     pixels[1] = pixels[3] = color1;
     bm.unlockPixels();
 
-    return SkShader::CreateBitmapShader(bm, SkShader::kRepeat_TileMode,
-                                            SkShader::kRepeat_TileMode);
+    return SkShader::MakeBitmapShader(bm, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);
 }
 
-static SkShader* make_shader1(const SkIPoint& size) {
+static sk_sp<SkShader> make_shader1(const SkIPoint& size) {
     SkPoint pts[] = { { 0, 0 },
                       { SkIntToScalar(size.fX), SkIntToScalar(size.fY) } };
     SkColor colors[] = { SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorRED };
-    return SkGradientShader::CreateLinear(pts, colors, nullptr,
+    return SkGradientShader::MakeLinear(pts, colors, nullptr,
                     SK_ARRAY_COUNT(colors), SkShader::kMirror_TileMode);
 }
 
 class VerticesView : public SampleView {
-    SkShader*   fShader0;
-    SkShader*   fShader1;
+    sk_sp<SkShader> fShader0;
+    sk_sp<SkShader> fShader1;
 
 public:
     VerticesView() {
@@ -70,11 +69,6 @@ public:
         this->setBGColor(SK_ColorGRAY);
     }
 
-    virtual ~VerticesView() {
-        SkSafeUnref(fShader0);
-        SkSafeUnref(fShader1);
-    }
-
 protected:
     // overrides from SkEventSink
     bool onQuery(SkEvent* evt) override {