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

tools/skdiff_utils.h

Index: tools/skdiff_utils.h
diff --git a/tools/skdiff_utils.h b/tools/skdiff_utils.h
index c535ae26b58ded4845d2a01b26dd6c015d298375..c799325e3607f0ec6227bfa2e600e192bfca9a41 100644
--- a/tools/skdiff_utils.h
+++ b/tools/skdiff_utils.h
@@ -25,7 +25,7 @@ bool are_buffers_equal(SkData* skdata1, SkData* skdata2);
 sk_sp<SkData> read_file(const char* file_path);
 
 /** Decodes the fileBits into the resource.fBitmap. Returns false on failure. */
-bool get_bitmap(SkData* fileBits, DiffResource& resource, bool sizeOnly);
+bool get_bitmap(sk_sp<SkData> fileBits, DiffResource& resource, bool sizeOnly);
 
 /** Writes the bitmap as a PNG to the path specified. */
 bool write_bitmap(const SkString& path, const SkBitmap& bitmap);