use Make instead of Create to return a shared shader

samplecode/SampleDitherBitmap.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SampleCode.h"
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
 #include "SkGradientShader.h"
 #include "SkPath.h"
 #include "SkUtils.h"
 #include "SkView.h"
 
 static void draw_rect(SkCanvas* canvas, const SkRect& r, const SkPaint& p) {
     canvas->drawRect(r, p);
 
     SkPaint frame(p);
     frame.setShader(nullptr);
     frame.setStyle(SkPaint::kStroke_Style);
     canvas->drawRect(r, frame);
 }
 
 static void draw_gradient(SkCanvas* canvas) {
     SkRect r = { 0, 0, SkIntToScalar(256), SkIntToScalar(32) };
     SkPoint pts[] = { { r.fLeft, r.fTop }, { r.fRight, r.fTop } };
     SkColor colors[] = { 0xFF000000, 0xFFFF0000 };
-    SkShader* s = SkGradientShader::CreateLinear(pts, colors, nullptr, 2,
-                                                 SkShader::kClamp_TileMode);
-
     SkPaint p;
-    p.setShader(s)->unref();
+    p.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2, SkShader::kClamp_TileMode));
     draw_rect(canvas, r, p);
 
     canvas->translate(0, SkIntToScalar(40));
     p.setDither(true);
     draw_rect(canvas, r, p);
 }
 
 static bool test_pathregion() {
     SkPath path;
     SkRegion region;
@@ skipping 98 matching lines @@
     }
 
 private:
     typedef SampleView INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static SkView* MyFactory() { return new DitherBitmapView; }
 static SkViewRegister reg(MyFactory);