Revert "remvoe duplicate impl for SkImageInfo flattening"

src/gpu/SkGr.cpp

Index: src/gpu/SkGr.cpp
diff --git a/src/gpu/SkGr.cpp b/src/gpu/SkGr.cpp
index a3f0eefa91f85a54b99565014f08ce92c799c2d4..c7ae0c8f36684f398043329a4b75e2f0b1bf9e72 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -258,33 +258,3 @@ GrPixelConfig SkBitmapConfig2GrPixelConfig(SkBitmap::Config config) {
             return kUnknown_GrPixelConfig;
     }
 }
-
-bool GrPixelConfig2ColorType(GrPixelConfig config, SkColorType* ctOut) {
-    SkColorType ct;
-    switch (config) {
-        case kAlpha_8_GrPixelConfig:
-            ct = kAlpha_8_SkColorType;
-            break;
-        case kIndex_8_GrPixelConfig:
-            ct = kIndex_8_SkColorType;
-            break;
-        case kRGB_565_GrPixelConfig:
-            ct = kRGB_565_SkColorType;
-            break;
-        case kRGBA_4444_GrPixelConfig:
-            ct = kARGB_4444_SkColorType;
-            break;
-        case kRGBA_8888_GrPixelConfig:
-            ct = kRGBA_8888_SkColorType;
-            break;
-        case kBGRA_8888_GrPixelConfig:
-            ct = kBGRA_8888_SkColorType;
-            break;
-        default:
-            return false;
-    }
-    if (ctOut) {
-        *ctOut = ct;
-    }
-    return true;
-}