remove dead SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER code

src/images/SkImageDecoder_libpng.cpp

Index: src/images/SkImageDecoder_libpng.cpp
diff --git a/src/images/SkImageDecoder_libpng.cpp b/src/images/SkImageDecoder_libpng.cpp
index 8a3e40ea19633b639448d1af73efabcdbd69ec54..e997fdbd7ed43528435817993896a24715f15128 100644
--- a/src/images/SkImageDecoder_libpng.cpp
+++ b/src/images/SkImageDecoder_libpng.cpp
@@ -614,12 +614,6 @@ bool SkPNGImageDecoder::getBitmapColorType(png_structp png_ptr, png_infop info_p
         }
     }
 
-#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
-    if (!this->chooseFromOneChoice(*colorTypep, origWidth, origHeight)) {
-        return false;
-    }
-#endif
-
     // If the image has alpha and the decoder wants unpremultiplied
     // colors, the only supported colortype is 8888.
     if (this->getRequireUnpremultipliedColors() && *hasAlphap) {