remove dead SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER code

src/images/SkImageDecoder_astc.cpp

Index: src/images/SkImageDecoder_astc.cpp
diff --git a/src/images/SkImageDecoder_astc.cpp b/src/images/SkImageDecoder_astc.cpp
index 30f42f05df2980456785feaa457f3b4e7681d389..96d28f8569654c01b7e20b19bd6c74ea06cf8529 100644
--- a/src/images/SkImageDecoder_astc.cpp
+++ b/src/images/SkImageDecoder_astc.cpp
@@ -117,13 +117,6 @@ SkImageDecoder::Result SkASTCImageDecoder::onDecode(SkStream* stream, SkBitmap*
     // Advance the buffer past the image dimensions
     buf += 9;
 
-#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
-    // should we allow the Chooser (if present) to pick a config for us???
-    if (!this->chooseFromOneChoice(kN32_SkColorType, width, height)) {
-        return kFailure;
-    }
-#endif
-
     // Setup the sampler...
     SkScaledBitmapSampler sampler(width, height, this->getSampleSize());