switch xfermodes over to sk_sp

tests/BlendTest.cpp

Index: tests/BlendTest.cpp
diff --git a/tests/BlendTest.cpp b/tests/BlendTest.cpp
index 612492d271ab7ca5036c2aa3de16d08fcddf88a6..ca9e46efd305f0e572bb960232594ad25b7dc1b6 100644
--- a/tests/BlendTest.cpp
+++ b/tests/BlendTest.cpp
@@ -80,7 +80,7 @@ DEF_TEST(Blend_premul_begets_premul, r) {
         if (mode == SkXfermode::kSrcOver_Mode) {
             return;  // TODO: can't create a SrcOver xfermode.
         }
-        SkAutoTUnref<SkXfermode> xfermode(SkXfermode::Create(mode));
+        auto xfermode(SkXfermode::Make(mode));
         SkASSERT(xfermode);
         // We'll test all alphas and legal color values, assuming all colors work the same.
         // This is not true for non-separable blend modes, but this test still can't hurt.