SkBlurImageFilter returns input when sigma = 0

In the current implementation, a blur filter is always created even in the
case when sigma.fX == 0 && sigma.fY == 0. This CL makes the blur filter
return input in this case.

BUG=568393

Review URL: https://codereview.chromium.org/1518643002

1 files changed, 3 insertions, 0 deletions

diff --git a/include/effects/SkBlurImageFilter.h b/include/effects/SkBlurImageFilter.h
index 7f62634a9e..5ae013d78e 100644
--- a/include/effects/SkBlurImageFilter.h
+++ b/include/effects/SkBlurImageFilter.h
@@ -15,6 +15,9 @@ class SK_API SkBlurImageFilter : public SkImageFilter {
 public:
     static SkImageFilter* Create(SkScalar sigmaX, SkScalar sigmaY, SkImageFilter* input = NULL,
                                  const CropRect* cropRect = NULL) {
+        if (0 == sigmaX && 0 == sigmaY && nullptr == cropRect) {
+            return SkSafeRef(input);
+        }
         return new SkBlurImageFilter(sigmaX, sigmaY, input, cropRect);
     }