switch surface to sk_sp

gm/drawbitmaprect.cpp

Index: gm/drawbitmaprect.cpp
diff --git a/gm/drawbitmaprect.cpp b/gm/drawbitmaprect.cpp
index 8ec7cee28e421968a612700af8ef81a3a33a6922..883e81b4177fec9508bcb1684d0875e52ee6edd4 100644
--- a/gm/drawbitmaprect.cpp
+++ b/gm/drawbitmaprect.cpp
@@ -36,10 +36,10 @@ static SkBitmap make_chessbm(int w, int h) {
 static sk_sp<SkImage> makebm(SkCanvas* origCanvas, SkBitmap* resultBM, int w, int h) {
     SkImageInfo info = SkImageInfo::MakeN32Premul(w, h);
     
-    SkAutoTUnref<SkSurface> surface(origCanvas->newSurface(info));
+    auto surface(origCanvas->makeSurface(info));
     if (nullptr == surface) {
         // picture canvas will return null, so fall-back to raster
-        surface.reset(SkSurface::NewRaster(info));
+        surface = SkSurface::MakeRaster(info);
     }
 
     SkCanvas* canvas = surface->getCanvas();