SkBlurImageFilter returns input when sigma = 0

bench/BlurImageFilterBench.cpp

Index: bench/BlurImageFilterBench.cpp
diff --git a/bench/BlurImageFilterBench.cpp b/bench/BlurImageFilterBench.cpp
index 7ed600632a1c3141ee1fab87dbcf6a53d7241f0e..f0a7a8eea0315dc54e2dd7e4fdb14cd4dd61ef32 100644
--- a/bench/BlurImageFilterBench.cpp
+++ b/bench/BlurImageFilterBench.cpp
@@ -80,7 +80,8 @@ protected:
 
         const SkImageFilter::CropRect* crop =
             fIsExpanded ? &cropRectLarge : fIsCropped ? &cropRect : nullptr;
-        paint.setImageFilter(SkBlurImageFilter::Create(fSigmaX, fSigmaY, input, crop))->unref();
+        SkAutoTUnref<SkImageFilter> blur(SkBlurImageFilter::Create(fSigmaX, fSigmaY, input, crop));
+        paint.setImageFilter(blur);
 
         for (int i = 0; i < loops; i++) {
             canvas->drawBitmap(fCheckerboard, kX, kY, &paint);