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/tests/PDFMetadataAttributeTest.cpp b/tests/PDFMetadataAttributeTest.cpp
index 6e7cc24..01351fa 100644
--- a/tests/PDFMetadataAttributeTest.cpp
+++ b/tests/PDFMetadataAttributeTest.cpp
@@ -29,7 +29,7 @@
                                                 metadata, nullptr, false);
     doc->beginPage(612.0f, 792.0f);
     doc->close();
-    sk_sp<SkData> data(pdf.copyToData());
+    sk_sp<SkData> data = pdf.detachAsData();
     static const char* expectations[] = {
         "/Title (A1)",
         "/Author (A2)",