This return_false is now only used on Android. Squelch a warning.

src/images/SkImageDecoder_libjpeg.cpp

Index: src/images/SkImageDecoder_libjpeg.cpp
diff --git a/src/images/SkImageDecoder_libjpeg.cpp b/src/images/SkImageDecoder_libjpeg.cpp
index 082adca04af610792b74aca6d8fdbe330c64144a..4f78865154fb3e99d7813975717e6504a58ab044 100644
--- a/src/images/SkImageDecoder_libjpeg.cpp
+++ b/src/images/SkImageDecoder_libjpeg.cpp
@@ -345,11 +345,13 @@ static bool return_false(const jpeg_decompress_struct& cinfo,
     return false;
 }
 
+#ifdef SK_BUILD_FOR_ANDROID
 static bool return_false(const jpeg_decompress_struct& cinfo,
                          const SkBitmap& bm, const char caller[]) {
     print_jpeg_decoder_errors(cinfo, bm.width(), bm.height(), caller);
     return false;
 }
+#endif
 
 static SkImageDecoder::Result return_failure(const jpeg_decompress_struct& cinfo,
                                              const SkBitmap& bm, const char caller[]) {