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

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2333713002

Review-Url: https://codereview.chromium.org/2333713002
diff --git a/samplecode/DecodeFile.h b/samplecode/DecodeFile.h
index 801d67c..b954af6 100644
--- a/samplecode/DecodeFile.h
+++ b/samplecode/DecodeFile.h
@@ -15,7 +15,7 @@
                                bool requireUnpremul = false) {
     SkASSERT(kIndex_8_SkColorType != colorType);
     sk_sp<SkData> data(SkData::MakeFromFileName(filename));
-    SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(data.get()));
+    SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(data));
     if (!codec) {
         return false;
     }