use Make instead of Create to return a shared shader

Partially updated call sites. Undefine the flag in SkSHader.h to convert the remaining sites.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1772463002

Review URL: https://codereview.chromium.org/1772463002
diff --git a/samplecode/SampleGradients.cpp b/samplecode/SampleGradients.cpp
index 2d6f7d4..5e9450e 100644
--- a/samplecode/SampleGradients.cpp
+++ b/samplecode/SampleGradients.cpp
@@ -10,10 +10,10 @@
 #include "SkCanvas.h"
 #include "SkGradientShader.h"
 
-static SkShader* setgrad(const SkRect& r, SkColor c0, SkColor c1) {
+static sk_sp<SkShader> setgrad(const SkRect& r, SkColor c0, SkColor c1) {
     SkColor colors[] = { c0, c1 };
     SkPoint pts[] = { { r.fLeft, r.fTop }, { r.fRight, r.fTop } };
-    return SkGradientShader::CreateLinear(pts, colors, nullptr, 2, SkShader::kClamp_TileMode);
+    return SkGradientShader::MakeLinear(pts, colors, nullptr, 2, SkShader::kClamp_TileMode);
 }
 
 static void test_alphagradients(SkCanvas* canvas) {
@@ -23,17 +23,17 @@
     SkPaint p, p2;
     p2.setStyle(SkPaint::kStroke_Style);
 
-    p.setShader(setgrad(r, 0xFF00FF00, 0x0000FF00))->unref();
+    p.setShader(setgrad(r, 0xFF00FF00, 0x0000FF00));
     canvas->drawRect(r, p);
     canvas->drawRect(r, p2);
 
     r.offset(0, r.height() + SkIntToScalar(4));
-    p.setShader(setgrad(r, 0xFF00FF00, 0x00000000))->unref();
+    p.setShader(setgrad(r, 0xFF00FF00, 0x00000000));
     canvas->drawRect(r, p);
     canvas->drawRect(r, p2);
 
     r.offset(0, r.height() + SkIntToScalar(4));
-    p.setShader(setgrad(r, 0xFF00FF00, 0x00FF0000))->unref();
+    p.setShader(setgrad(r, 0xFF00FF00, 0x00FF0000));
     canvas->drawRect(r, p);
     canvas->drawRect(r, p2);
 }
@@ -63,49 +63,49 @@
     { 5, gColors, gPos2 }
 };
 
-static SkShader* MakeLinear(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm) {
-    return SkGradientShader::CreateLinear(pts, data.fColors, data.fPos, data.fCount, tm);
+static sk_sp<SkShader> MakeLinear(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm) {
+    return SkGradientShader::MakeLinear(pts, data.fColors, data.fPos, data.fCount, tm);
 }
 
-static SkShader* MakeRadial(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm) {
+static sk_sp<SkShader> MakeRadial(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm) {
     SkPoint center;
     center.set(SkScalarAve(pts[0].fX, pts[1].fX),
                SkScalarAve(pts[0].fY, pts[1].fY));
-    return SkGradientShader::CreateRadial(center, center.fX, data.fColors,
-                                          data.fPos, data.fCount, tm);
+    return SkGradientShader::MakeRadial(center, center.fX, data.fColors,
+                                        data.fPos, data.fCount, tm);
 }
 
-static SkShader* MakeSweep(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm) {
+static sk_sp<SkShader> MakeSweep(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm) {
     SkPoint center;
     center.set(SkScalarAve(pts[0].fX, pts[1].fX),
                SkScalarAve(pts[0].fY, pts[1].fY));
-    return SkGradientShader::CreateSweep(center.fX, center.fY, data.fColors, data.fPos, data.fCount);
+    return SkGradientShader::MakeSweep(center.fX, center.fY, data.fColors, data.fPos, data.fCount);
 }
 
-static SkShader* Make2Conical(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm) {
+static sk_sp<SkShader> Make2Conical(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm) {
     SkPoint center0, center1;
     center0.set(SkScalarAve(pts[0].fX, pts[1].fX),
                 SkScalarAve(pts[0].fY, pts[1].fY));
     center1.set(SkScalarInterp(pts[0].fX, pts[1].fX, SkIntToScalar(3)/5),
                 SkScalarInterp(pts[0].fY, pts[1].fY, SkIntToScalar(1)/4));
-    return SkGradientShader::CreateTwoPointConical(
+    return SkGradientShader::MakeTwoPointConical(
                             center1, (pts[1].fX - pts[0].fX) / 7,
                             center0, (pts[1].fX - pts[0].fX) / 2,
                             data.fColors, data.fPos, data.fCount, tm);
 }
 
-static SkShader* Make2ConicalConcentric(const SkPoint pts[2], const GradData& data,
+static sk_sp<SkShader> Make2ConicalConcentric(const SkPoint pts[2], const GradData& data,
                                        SkShader::TileMode tm) {
     SkPoint center;
     center.set(SkScalarAve(pts[0].fX, pts[1].fX),
                SkScalarAve(pts[0].fY, pts[1].fY));
-    return SkGradientShader::CreateTwoPointConical(
+    return SkGradientShader::MakeTwoPointConical(
                             center, (pts[1].fX - pts[0].fX) / 7,
                             center, (pts[1].fX - pts[0].fX) / 2,
                             data.fColors, data.fPos, data.fCount, tm);
 }
 
-typedef SkShader* (*GradMaker)(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm);
+typedef sk_sp<SkShader> (*GradMaker)(const SkPoint pts[2], const GradData& data, SkShader::TileMode tm);
 
 static const GradMaker gGradMakers[] = {
     MakeLinear, MakeRadial, MakeSweep, Make2Conical, Make2ConicalConcentric
@@ -120,8 +120,7 @@
     }
 
 protected:
-    // overrides from SkEventSink
-    virtual bool onQuery(SkEvent* evt) {
+    bool onQuery(SkEvent* evt) override {
         if (SampleCode::TitleQ(*evt)) {
             SampleCode::TitleR(evt, "Gradients");
             return true;
@@ -129,7 +128,7 @@
         return this->INHERITED::onQuery(evt);
     }
 
-    virtual void onDrawContent(SkCanvas* canvas) {
+    void onDrawContent(SkCanvas* canvas) override {
         SkPoint pts[2] = {
             { 0, 0 },
             { SkIntToScalar(100), SkIntToScalar(100) }
@@ -146,9 +145,7 @@
             for (size_t i = 0; i < SK_ARRAY_COUNT(gGradData); i++) {
                 canvas->save();
                 for (size_t j = 0; j < SK_ARRAY_COUNT(gGradMakers); j++) {
-                    SkShader* shader;
-                    shader = gGradMakers[j](pts, gGradData[i], (SkShader::TileMode)tm);
-                    paint.setShader(shader)->unref();
+                    paint.setShader(gGradMakers[j](pts, gGradData[i], (SkShader::TileMode)tm));
                     canvas->drawRect(r, paint);
                     canvas->translate(0, SkIntToScalar(120));
                 }