Subset decoding benchmarks

bench/SubsetZoomBench.h

Index: bench/SubsetZoomBench.h
diff --git a/bench/SubsetZoomBench.h b/bench/SubsetZoomBench.h
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+/*
+ * Copyright 2015 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 "SkImageDecoder.h"
+#include "SkImageInfo.h"
+#include "SkStream.h"
+#include "SkString.h"
+
+/*
+ *
+ * This benchmark is designed to test the performance of subset decoding.
+ * Choose subsets to mimic a user zooming in or out on a photo.
+ *
+ */
+class SubsetZoomBench : public Benchmark {
+public:
+
+    SubsetZoomBench(const SkString& path,
+                    SkColorType colorType,
+                    uint32_t subsetWidth,
+                    uint32_t subsetHeight,
+                    bool useCodec);
+
+protected:
+    const char* onGetName() override;
+    bool isSuitableFor(Backend backend) override;
+    void onDraw(const int n, SkCanvas* canvas) override;
+
+private:
+    SkString                      fName;
+    SkColorType                   fColorType;
+    const uint32_t                fSubsetWidth;
+    const uint32_t                fSubsetHeight;
+    const bool                    fUseCodec;
+    SkAutoTDelete<SkMemoryStream> fStream;
+    typedef Benchmark INHERITED;
+};