Add timing SkCodec to nanobench.

bench/CodecBench.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
+#ifndef CodecBench_DEFINED
+#define CodecBench_DEFINED
+
 #include "Benchmark.h"
-#include "SkImageDecoder.h"
 #include "SkImageInfo.h"
 #include "SkStream.h"
 #include "SkString.h"
 
-/*
- *
- * This benchmark is designed to test the performance of image decoding.
- * It is invoked from the nanobench.cpp file.
- *
+class SkData;
+
+/**
+ *  Time SkCodec.
  */
-class DecodingBench : public Benchmark {
+class CodecBench : public Benchmark {
 public:
-    DecodingBench(SkString path, SkColorType colorType);
+    // Calls encoded->ref()
+    CodecBench(SkString basename, SkData* encoded, SkColorType colorType);
 
 protected:
     const char* onGetName() override;
     bool isSuitableFor(Backend backend) override;
     void onDraw(const int n, SkCanvas* canvas) override;
-    
+
 private:
-    SkString fName;
-    SkColorType fColorType;
-    SkAutoTDelete<SkMemoryStream> fStream;
-    SkAutoTDelete<SkImageDecoder> fDecoder;
+    SkString                        fName;
+    const SkColorType               fColorType;
+    SkAutoTDelete<SkMemoryStream>   fStream;
     typedef Benchmark INHERITED;
 };
+#endif // CodecBench_DEFINED