Add nanobench tests for BitmapRegionDecoder

bench/CodecBench.cpp

Index: bench/CodecBench.cpp
diff --git a/bench/CodecBench.cpp b/bench/CodecBench.cpp
index 1e6b5207bfcb1318fd38667aab6763dc4bdc225a..a21aae1f0b909b73d6ab148290fc99895ad6e44d 100644
--- a/bench/CodecBench.cpp
+++ b/bench/CodecBench.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "CodecBench.h"
+#include "CodecBenchPriv.h"
 #include "SkBitmap.h"
 #include "SkCodec.h"
 #include "SkOSFile.h"
@@ -15,21 +16,7 @@ CodecBench::CodecBench(SkString baseName, SkData* encoded, SkColorType colorType
     , fData(SkRef(encoded))
 {
     // Parse filename and the color type to give the benchmark a useful name
-    const char* colorName;
-    switch(colorType) {
-        case kN32_SkColorType:
-            colorName = "N32";
-            break;
-        case kRGB_565_SkColorType:
-            colorName = "565";
-            break;
-        case kAlpha_8_SkColorType:
-            colorName = "Alpha8";
-            break;
-        default:
-            colorName = "Unknown";
-    }
-    fName.printf("Codec_%s_%s", baseName.c_str(), colorName);
+    fName.printf("Codec_%s_%s", baseName.c_str(), color_type_to_str(colorType));
 #ifdef SK_DEBUG
     // Ensure that we can create an SkCodec from this data.
     SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(fData));