take gr-context parameter to refEncoded, indicating a desire for only gpu-specific formats

src/core/SkImageGenerator.cpp

Index: src/core/SkImageGenerator.cpp
diff --git a/src/core/SkImageGenerator.cpp b/src/core/SkImageGenerator.cpp
index dcd3ad00b17e812d27b647360b9f4529463124f5..7d71b6701c32c6da0741b528d8ec7ddc7b1cc510 100644
--- a/src/core/SkImageGenerator.cpp
+++ b/src/core/SkImageGenerator.cpp
@@ -137,7 +137,7 @@ bool SkImageGenerator::generateScaledPixels(const SkISize& scaledSize,
 
 /////////////////////////////////////////////////////////////////////////////////////////////
 
-SkData* SkImageGenerator::onRefEncodedData() {
+SkData* SkImageGenerator::onRefEncodedData(SK_REFENCODEDDATA_CTXPARAM) {
     return nullptr;
 }