Add nanobench tests for BitmapRegionDecoder

bench/subset/SubsetBenchPriv.h

Index: bench/subset/SubsetBenchPriv.h
diff --git a/bench/subset/SubsetBenchPriv.h b/bench/subset/SubsetBenchPriv.h
index 02f7040a227fa2b4b5d2a0f4164a8dcfbb68e4b3..7e1dfb953068e4fa5a328b6920070542668794ad 100644
--- a/bench/subset/SubsetBenchPriv.h
+++ b/bench/subset/SubsetBenchPriv.h
@@ -13,26 +13,6 @@
 #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.