SkBlurImageFilter returns input when sigma = 0

gm/imageblur2.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkBlurImageFilter.h"
 #include "SkRandom.h"
@@ skipping 40 matching lines @@
         SkScalar dx = WIDTH / sigmaCount;
         SkScalar dy = HEIGHT / sigmaCount;
         const SkScalar textSize = 12;
 
         for (int x = 0; x < sigmaCount; x++) {
             SkScalar sigmaX = kBlurSigmas[x];
             for (int y = 0; y < sigmaCount; y++) {
                 SkScalar sigmaY = kBlurSigmas[y];
 
                 SkPaint paint;
-                paint.setImageFilter(SkBlurImageFilter::Create(sigmaX, sigmaY))->unref();
+                SkAutoTUnref<SkImageFilter> blur(SkBlurImageFilter::Create(sigmaX, sigmaY));
+                paint.setImageFilter(blur);
                 canvas->saveLayer(nullptr, &paint);
 
                 SkRandom rand;
                 SkPaint textPaint;
                 textPaint.setAntiAlias(false);
                 textPaint.setColor(sk_tool_utils::color_to_565(rand.nextBits(24) | 0xFF000000));
                 sk_tool_utils::set_portable_typeface(&textPaint);
                 textPaint.setTextSize(textSize);
 
                 for (int i = 0; i < testStringCount; i++) {
@@ skipping 13 matching lines @@
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new BlurImageFilter; }
 static GMRegistry reg(MyFactory);
 
 }