Add nanobench tests for BitmapRegionDecoder

bench/subset/SubsetBenchPriv.h

 /*
  * Copyright 2015 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SubsetBenchPriv_DEFINED
 #define SubsetBenchPriv_DEFINED
 
 #include "SkCodec.h"
 #include "SkData.h"
 #include "SkImageGenerator.h"
 
 /*
- * Convert the color type to a string
- */
-static const char* get_color_name(SkColorType colorType) {
-    switch(colorType) {
-        case kN32_SkColorType:
-            return "N32";
-        case kRGB_565_SkColorType:
-            return "565";
-        case kGray_8_SkColorType:
-            return "Gray8";
-        case kIndex_8_SkColorType:
-            return "Index8";
-        case kAlpha_8_SkColorType:
-            return "Alpha8";
-        default:
-            return "Unknown";
-    }
-}
-
-/*
  * If we plan to decode to kIndex8, we must create a color table and pass it to the
  * bitmap when we allocate pixels.  Otherwise, we simply allocate pixels using the
  * decode info.
  */
 static inline void alloc_pixels(SkBitmap* bitmap, const SkImageInfo& info, SkPMColor* colors,
         int colorCount) {
     if (kIndex_8_SkColorType == info.colorType()) {
         SkAutoTUnref<SkColorTable> colorTable(new SkColorTable(colors, colorCount));
         bitmap->allocPixels(info, nullptr, colorTable);
     } else {
         bitmap->allocPixels(info);
     }
 }
 
 #endif // SubsetBenchPriv_DEFINED