switch surface to sk_sp

tools/skhello.cpp

Index: tools/skhello.cpp
diff --git a/tools/skhello.cpp b/tools/skhello.cpp
index 61502a6fb8236602c3dc80e7507e216411c582ab..d033641bf1f1ea9d3cbb4f675e62d25bbc22f645 100644
--- a/tools/skhello.cpp
+++ b/tools/skhello.cpp
@@ -34,7 +34,7 @@ static void doDraw(SkCanvas* canvas, const SkPaint& paint, const char text[]) {
 static bool do_surface(int w, int h, const char path[], const char text[],
                        const SkPaint& paint) {
     SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
-    SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(w, h, &props));
+    sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(w, h, &props));
     doDraw(surface->getCanvas(), paint, text);
 
     sk_sp<SkImage> image(surface->makeImageSnapshot());