switch xfermodes over to sk_sp

gm/xfermodes2.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "gm.h"
 #include "SkBitmap.h"
 #include "SkShader.h"
 #include "SkXfermode.h"
@@ skipping 23 matching lines @@
         SkPaint labelP;
         labelP.setAntiAlias(true);
         sk_tool_utils::set_portable_typeface(&labelP);
         labelP.setTextAlign(SkPaint::kCenter_Align);
 
         const int W = 6;
 
         SkScalar x = 0, y = 0;
         for (size_t m = 0; m <= SkXfermode::kLastMode; m++) {
             SkXfermode::Mode mode = static_cast<SkXfermode::Mode>(m);
-            SkXfermode* xm = SkXfermode::Create(mode);
-            SkAutoUnref aur(xm);
 
             canvas->save();
 
             canvas->translate(x, y);
             SkPaint p;
             p.setAntiAlias(false);
             p.setStyle(SkPaint::kFill_Style);
             p.setShader(fBG);
             SkRect r = SkRect::MakeWH(w, h);
             canvas->drawRect(r, p);
 
             canvas->saveLayer(&r, nullptr);
 
             p.setShader(fDst);
             canvas->drawRect(r, p);
             p.setShader(fSrc);
-            p.setXfermode(xm);
+            p.setXfermode(SkXfermode::Make(mode));
             canvas->drawRect(r, p);
 
             canvas->restore();
 
             r.inset(-SK_ScalarHalf, -SK_ScalarHalf);
             p.setStyle(SkPaint::kStroke_Style);
             p.setShader(nullptr);
             p.setXfermode(nullptr);
             canvas->drawRect(r, p);
 
@@ skipping 67 matching lines @@
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new Xfermodes2GM; }
 static GMRegistry reg(MyFactory);
 
 }