Update SkImageSource to sk_sp

gm/imagesource2.cpp

Index: gm/imagesource2.cpp
diff --git a/gm/imagesource2.cpp b/gm/imagesource2.cpp
index 3a3d27360d8097728a46b2f46437ba4cb7ce24e5..ba6af46cfbd547bc4405ff259726ef35a1f33ff1 100644
--- a/gm/imagesource2.cpp
+++ b/gm/imagesource2.cpp
@@ -60,15 +60,13 @@ protected:
     }
 
     void onDraw(SkCanvas* canvas) override {
-        SkRect srcRect = SkRect::MakeLTRB(0, 0,
-                                          SkIntToScalar(kImageSize), SkIntToScalar(kImageSize));
-        SkRect dstRect = SkRect::MakeLTRB(0.75f, 0.75f, 225.75f, 225.75f);
-
-        SkAutoTUnref<SkImageFilter> filter(
-            SkImageSource::Create(fImage.get(), srcRect, dstRect, fFilter));
+        const SkRect srcRect = SkRect::MakeLTRB(0, 0,
+                                                SkIntToScalar(kImageSize),
+                                                SkIntToScalar(kImageSize));
+        const SkRect dstRect = SkRect::MakeLTRB(0.75f, 0.75f, 225.75f, 225.75f);
 
         SkPaint p;
-        p.setImageFilter(filter);
+        p.setImageFilter(SkImageSource::Make(fImage, srcRect, dstRect, fFilter));
 
         canvas->saveLayer(nullptr, &p);
         canvas->restore();