Add bench for image encodes

bench/EncoderBench.cpp

+/*
+ * Copyright 2016 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 "Resources.h"
+#include "SkBitmap.h"
+#include "SkData.h"
+#include "SkImageEncoder.h"
+
+class EncodeBench : public Benchmark {
+public:
+    EncodeBench(const char* filename, SkImageEncoder::Type type, int quality)
+        : fFilename(filename)
+        , fType(type)
+        , fQuality(quality)
+    {
+        // Set the name of the bench
+        SkString name("Encode_");
+        name.append(filename);
+        name.append("_");
+        switch (type) {
+            case SkImageEncoder::kJPEG_Type:
+                name.append("JPEG");
+                break;
+            case SkImageEncoder::kPNG_Type:
+                name.append("PNG");
+                break;
+            case SkImageEncoder::kWEBP_Type:
+                name.append("WEBP");
+                break;
+            default:
+                name.append("Unknown");
+                break;
+        }
+        
+        fName = name;
+    }
+
+    bool isSuitableFor(Backend backend) override { return backend == kNonRendering_Backend; }
+    
+    const char* onGetName() override { return fName.c_str(); }
+    
+    void onPreDraw(SkCanvas*) override {
+#ifdef SK_DEBUG
+        bool result =
+#endif
+        GetResourceAsBitmap(fFilename, &fBitmap);
+        SkASSERT(result);
+    }
+
+    void onDraw(int loops, SkCanvas*) override {
+        for (int i = 0; i < loops; i++) {
+            SkAutoTUnref<SkData> data(SkImageEncoder::EncodeData(fBitmap, fType, fQuality));
+            SkASSERT(data);
+        }
+    }
+
+private:
+    const char*                fFilename;
+    const SkImageEncoder::Type fType;
+    const int                  fQuality;
+    SkString                   fName;
+    SkBitmap                   fBitmap;
+};
+
+
+// The Android Photos app uses a quality of 90 on JPEG encodes
+DEF_BENCH(return new EncodeBench("mandrill_512.png", SkImageEncoder::kJPEG_Type, 90));
+DEF_BENCH(return new EncodeBench("color_wheel.jpg", SkImageEncoder::kJPEG_Type, 90));
+
+// PNG encodes are lossless so quality should be ignored
+DEF_BENCH(return new EncodeBench("mandrill_512.png", SkImageEncoder::kPNG_Type, 90));
+DEF_BENCH(return new EncodeBench("color_wheel.jpg", SkImageEncoder::kPNG_Type, 90));
+
+// TODO: What is the appropriate quality to use to benchmark WEBP encodes?
+DEF_BENCH(return new EncodeBench("mandrill_512.png", SkImageEncoder::kWEBP_Type, 90));
+DEF_BENCH(return new EncodeBench("color_wheel.jpg", SkImageEncoder::kWEBP_Type, 90));