switch maskfilters to sk_sp

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1852113003

Review URL: https://codereview.chromium.org/1852113003
diff --git a/gm/largeglyphblur.cpp b/gm/largeglyphblur.cpp
index a4c1123..6ffe953 100644
--- a/gm/largeglyphblur.cpp
+++ b/gm/largeglyphblur.cpp
@@ -26,8 +26,7 @@
         static const SkScalar kSigma = SkBlurMask::ConvertRadiusToSigma(SkIntToScalar(40));
 
         SkPaint blurPaint(paint);
-        SkAutoTUnref<SkMaskFilter> mf(SkBlurMaskFilter::Create(kNormal_SkBlurStyle, kSigma));
-        blurPaint.setMaskFilter(mf);
+        blurPaint.setMaskFilter(SkBlurMaskFilter::Make(kNormal_SkBlurStyle, kSigma));
 
         SkTextBlobBuilder builder;