switch xfermodes over to sk_sp

samplecode/SampleAARectModes.cpp

Index: samplecode/SampleAARectModes.cpp
diff --git a/samplecode/SampleAARectModes.cpp b/samplecode/SampleAARectModes.cpp
index 43392235c9fed3a0fee0e1dfb9aad45176ca299c..8066e682b18b2cb17a2528a2fa6594c9aa2d4e87 100644
--- a/samplecode/SampleAARectModes.cpp
+++ b/samplecode/SampleAARectModes.cpp
@@ -35,9 +35,7 @@ const int gHeight = 64;
 const SkScalar W = SkIntToScalar(gWidth);
 const SkScalar H = SkIntToScalar(gHeight);
 
-static SkScalar drawCell(SkCanvas* canvas, SkXfermode* mode,
-                         SkAlpha a0, SkAlpha a1) {
-
+static SkScalar drawCell(SkCanvas* canvas, const sk_sp<SkXfermode>& mode, SkAlpha a0, SkAlpha a1) {
     SkPaint paint;
     paint.setAntiAlias(true);
 
@@ -109,17 +107,15 @@ protected:
                     canvas->translate(W * 5, 0);
                     canvas->save();
                 }
-                SkXfermode* mode = SkXfermode::Create(gModes[i].fMode);
+                sk_sp<SkXfermode> mode = SkXfermode::Make(gModes[i].fMode);
 
                 canvas->drawRect(bounds, fBGPaint);
                 canvas->saveLayer(&bounds, nullptr);
-                SkScalar dy = drawCell(canvas, mode,
-                                       gAlphaValue[alpha & 1],
+                SkScalar dy = drawCell(canvas, mode, gAlphaValue[alpha & 1],
                                        gAlphaValue[alpha & 2]);
                 canvas->restore();
 
                 canvas->translate(0, dy * 5 / 4);
-                SkSafeUnref(mode);
             }
             canvas->restore();
             canvas->restore();