This fixes a bug introduced in: https://codereview.chromium.org/1961953002/ (Reland of Simplify SkGpuBlurUtils::GaussianBlur method) Although the 'canOverwriteSrc' flag is/was being used I still believe we're better off re-adding it after the mask-blur refactoring finishes. GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2100873002 Review-Url: https://codereview.chromium.org/2100873002
