switch surface to sk_sp

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1817383002
CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Ubuntu-GCC-x86_64-Release-CMake-Trybot,Build-Mac-Clang-x86_64-Release-CMake-Trybot

Review URL: https://codereview.chromium.org/1817383002
diff --git a/gm/bigtileimagefilter.cpp b/gm/bigtileimagefilter.cpp
index 84b9816..7d3d3af 100644
--- a/gm/bigtileimagefilter.cpp
+++ b/gm/bigtileimagefilter.cpp
@@ -11,7 +11,7 @@
 #include "gm.h"
 
 static sk_sp<SkImage> create_circle_texture(int size, SkColor color) {
-    SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(size, size));
+    auto surface(SkSurface::MakeRasterN32Premul(size, size));
     SkCanvas* canvas = surface->getCanvas();
     canvas->clear(0xFF000000);