Update SkOffsetImageFilter to sk_sp

TBR=reed@google.com

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1842193002

Review URL: https://codereview.chromium.org/1842193002
diff --git a/gm/lighting.cpp b/gm/lighting.cpp
index af102d7..e0a317d 100644
--- a/gm/lighting.cpp
+++ b/gm/lighting.cpp
@@ -80,7 +80,7 @@
 
         SkImageFilter::CropRect cropRect(SkRect::MakeXYWH(20, 10, 60, 65));
         SkImageFilter::CropRect fullSizeCropRect(SkRect::MakeXYWH(0, 0, 100, 100));
-        SkAutoTUnref<SkImageFilter> noopCropped(SkOffsetImageFilter::Create(0, 0, nullptr, &cropRect));
+        sk_sp<SkImageFilter> noopCropped(SkOffsetImageFilter::Make(0, 0, nullptr, &cropRect));
 
         int y = 0;
         for (int i = 0; i < 3; i++) {