Add nanobench tests for BitmapRegionDecoder

bench/BitmapRegionDecoderBench.cpp

Index: bench/BitmapRegionDecoderBench.cpp
diff --git a/bench/BitmapRegionDecoderBench.cpp b/bench/BitmapRegionDecoderBench.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..77d342331d90ef0b6246069de27ccf096565a63f
--- /dev/null
+++ b/bench/BitmapRegionDecoderBench.cpp
@@ -0,0 +1,68 @@
+/*
+ * 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 "BitmapRegionDecoderBench.h"
+#include "CodecBenchPriv.h"
+#include "SkBitmap.h"
+#include "SkCodecTools.h"
+#include "SkOSFile.h"
+
+BitmapRegionDecoderBench::BitmapRegionDecoderBench(const char* baseName, SkData* encoded,
+        SkBitmapRegionDecoderInterface::Strategy strategy, SkColorType colorType,
+        uint32_t sampleSize, const SkIRect& subset)
+    : fBRD(nullptr)
+    , fData(SkRef(encoded))
+    , fStrategy(strategy)
+    , fColorType(colorType)
+    , fSampleSize(sampleSize)
+    , fSubset(subset)
+{
+    // Choose a useful name for the region decoding strategy
+    const char* strategyName;
+    switch (strategy) {
+        case SkBitmapRegionDecoderInterface::kOriginal_Strategy:
+            strategyName = "Original";
+            break;
+        case SkBitmapRegionDecoderInterface::kCanvas_Strategy:
+            strategyName = "Canvas";
+            break;
+        default:
+            SkASSERT(false);
+            strategyName = "";
+            break;
+    }
+
+    // Choose a useful name for the color type
+    const char* colorName = color_type_to_str(colorType);
+
+    fName.printf("BRD_%s_%s_%s", baseName, strategyName, colorName);
+    if (1 != sampleSize) {
+        fName.appendf("_%.3f", get_scale_from_sample_size(sampleSize));
+    }
+}
+
+const char* BitmapRegionDecoderBench::onGetName() {
+    return fName.c_str();
+}
+
+bool BitmapRegionDecoderBench::isSuitableFor(Backend backend) {
+    return kNonRendering_Backend == backend;
+}
+
+void BitmapRegionDecoderBench::onPreDraw() {
+    SkStreamRewindable* stream = new SkMemoryStream(fData);
+    fBRD.reset(SkBitmapRegionDecoderInterface::CreateBitmapRegionDecoder(stream, fStrategy));
+}
+
+void BitmapRegionDecoderBench::onDraw(const int n, SkCanvas* canvas) {
+    SkAutoTDelete<SkBitmap> bitmap;
+    for (int i = 0; i < n; i++) {
+        bitmap.reset(fBRD->decodeRegion(fSubset.left(), fSubset.top(), fSubset.width(),
+                fSubset.height(), fSampleSize, fColorType));
+        SkASSERT(nullptr != bitmap.get());
+    }
+}