change SkStreams to work with sk_sp<SkData> instead of SkData*

src/images/SkImageEncoder.cpp

Index: src/images/SkImageEncoder.cpp
diff --git a/src/images/SkImageEncoder.cpp b/src/images/SkImageEncoder.cpp
index 22bbc57c2f593a083734311f0c2dadb5f4994947..023885f4591859f82f7ea0e1bbd447b449a7ea64 100644
--- a/src/images/SkImageEncoder.cpp
+++ b/src/images/SkImageEncoder.cpp
@@ -31,7 +31,7 @@ SkData* SkImageEncoder::encodeData(const SkBitmap& bm, int quality) {
     SkDynamicMemoryWStream stream;
     quality = SkMin32(100, SkMax32(0, quality));
     if (this->onEncode(&stream, bm, quality)) {
-        return stream.copyToData();
+        return stream.detachAsData().release();
     }
     return nullptr;
 }