Add some benches for SkArithmeticMode.

bench/XfermodeBench.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 "Benchmark.h"
+#include "SkArithmeticMode.h"
 #include "SkCanvas.h"
 #include "SkPaint.h"
 #include "SkRandom.h"
 #include "SkString.h"
 #include "SkXfermode.h"
 
 // Benchmark that draws non-AA rects or AA text with an SkXfermode::Mode.
 class XfermodeBench : public Benchmark {
 public:
     XfermodeBench(SkXfermode::Mode mode, bool aa) {
         fXfermode = SkXfermode::Make(mode);
         fAA = aa;
         SkASSERT(fXfermode.get() || SkXfermode::kSrcOver_Mode == mode);
         fName.printf("Xfermode_%s%s", SkXfermode::ModeName(mode), aa ? "_aa" : "");
     }
 
-    XfermodeBench(SkXfermode* xferMode, const char* name, bool aa) {
-        SkASSERT(xferMode);
-        fXfermode.reset(xferMode);
+    XfermodeBench(sk_sp<SkXfermode> xferMode, const char* name, bool aa) {
+        fXfermode = xferMode;
         fAA = aa;
         fName.printf("Xfermode_%s%s", name, aa ? "_aa" : "");
     }
 
 protected:
     const char* onGetName() override { return fName.c_str(); }
 
     void onDraw(int loops, SkCanvas* canvas) override {
         const char* text = "Hamburgefons";
         size_t len = strlen(text);
@@ skipping 90 matching lines @@
 BENCH(SkXfermode::kSoftLight_Mode)
 BENCH(SkXfermode::kDifference_Mode)
 BENCH(SkXfermode::kExclusion_Mode)
 BENCH(SkXfermode::kMultiply_Mode)
 
 BENCH(SkXfermode::kHue_Mode)
 BENCH(SkXfermode::kSaturation_Mode)
 BENCH(SkXfermode::kColor_Mode)
 BENCH(SkXfermode::kLuminosity_Mode)
 
+DEF_BENCH( return new XfermodeBench(SkArithmeticMode::Make(0.2f, -0.3f, 1.5f, -0.7f, false), \
+                                    "arithmetic", false); )
+DEF_BENCH( return new XfermodeBench(SkArithmeticMode::Make(0.2f, -0.3f, 1.5f, -0.7f, true), \
+                                    "arithmetic_enforce_pm", false); )
+DEF_BENCH( return new XfermodeBench(SkArithmeticMode::Make(0.2f, -0.3f, 1.5f, -0.7f, false), \
+                                    "arithmetic", true); )
+DEF_BENCH( return new XfermodeBench(SkArithmeticMode::Make(0.2f, -0.3f, 1.5f, -0.7f, true), \
+                                    "arithmetic_enforce_pm", true); )
+
 DEF_BENCH(return new XferCreateBench;)