implement readPixels and writePixels natively, w/o using the (deprecated)

tools/sk_tool_utils.cpp

 #include "sk_tool_utils.h"
 
 namespace sk_tool_utils {
 
 const char* colortype_name(SkColorType ct) {
     switch (ct) {
         case kUnknown_SkColorType:      return "Unknown";
         case kAlpha_8_SkColorType:      return "Alpha_8";
         case kIndex_8_SkColorType:      return "Index_8";
         case kARGB_4444_SkColorType:    return "ARGB_4444";
         case kRGB_565_SkColorType:      return "RGB_565";
         case kRGBA_8888_SkColorType:    return "RGBA_8888";
         case kBGRA_8888_SkColorType:    return "BGRA_8888";
         default:
             SkASSERT(false);
             return "unexpected colortype";
     }
 }
 
-void config8888_to_imagetypes(SkCanvas::Config8888 config, SkColorType* ct, SkAlphaType* at) {
-    switch (config) {
-        case SkCanvas::kNative_Premul_Config8888:
-            *ct = kPMColor_SkColorType;
-            *at = kPremul_SkAlphaType;
-            break;
-        case SkCanvas::kNative_Unpremul_Config8888:
-            *ct = kPMColor_SkColorType;
-            *at = kUnpremul_SkAlphaType;
-            break;
-        case SkCanvas::kBGRA_Premul_Config8888:
-            *ct = kBGRA_8888_SkColorType;
-            *at = kPremul_SkAlphaType;
-            break;
-        case SkCanvas::kBGRA_Unpremul_Config8888:
-            *ct = kBGRA_8888_SkColorType;
-            *at = kUnpremul_SkAlphaType;
-            break;
-        case SkCanvas::kRGBA_Premul_Config8888:
-            *ct = kRGBA_8888_SkColorType;
-            *at = kPremul_SkAlphaType;
-            break;
-        case SkCanvas::kRGBA_Unpremul_Config8888:
-            *ct = kRGBA_8888_SkColorType;
-            *at = kUnpremul_SkAlphaType;
-            break;
-        default:
-            SkASSERT(0);
-    }
-}
-
 void write_pixels(SkCanvas* canvas, const SkBitmap& bitmap, int x, int y,
                   SkColorType colorType, SkAlphaType alphaType) {
     SkBitmap tmp(bitmap);
     tmp.lockPixels();
 
     SkImageInfo info = tmp.info();
     info.fColorType = colorType;
     info.fAlphaType = alphaType;
 
     canvas->writePixels(info, tmp.getPixels(), tmp.rowBytes(), x, y);
 }
 
 }