SkData need not be a Flattenable, since it does not need subclass/factories

src/image/SkDataPixelRef.cpp

Index: src/image/SkDataPixelRef.cpp
diff --git a/src/image/SkDataPixelRef.cpp b/src/image/SkDataPixelRef.cpp
index 980b4f145176b4ed5977406ba4c3f5095c02815f..0524243366c16cdf079cd8434dcd10d31500fc54 100644
--- a/src/image/SkDataPixelRef.cpp
+++ b/src/image/SkDataPixelRef.cpp
@@ -29,11 +29,11 @@ void SkDataPixelRef::onUnlockPixels() {
 
 void SkDataPixelRef::flatten(SkFlattenableWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
-    buffer.writeFlattenable(fData);
+    buffer.writeDataAsByteArray(fData);
 }
 
 SkDataPixelRef::SkDataPixelRef(SkFlattenableReadBuffer& buffer)
         : INHERITED(buffer, NULL) {
-    fData = (SkData*)buffer.readFlattenable();
+    fData = buffer.readByteArrayAsData();
     this->setPreLocked(const_cast<void*>(fData->data()), NULL);
 }