remove DownSample imagefilter

include/effects/SkTestImageFilters.h

-/*
- * Copyright 2011 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef _SkTestImageFilters_h
-#define _SkTestImageFilters_h
-
-#include "SkImageFilter.h"
-#include "SkPoint.h"
-
-// Fun mode that scales down (only) and then scales back up to look pixelated
-class SK_API SkDownSampleImageFilter : public SkImageFilter {
-public:
-    static sk_sp<SkImageFilter> Make(SkScalar scale, sk_sp<SkImageFilter> input);
-
-    SK_TO_STRING_OVERRIDE()
-    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDownSampleImageFilter)
-
-#ifdef SK_SUPPORT_LEGACY_IMAGEFILTER_PTR
-    static SkImageFilter* Create(SkScalar scale, SkImageFilter* input = nullptr) {
-        return Make(scale, sk_ref_sp<SkImageFilter>(input)).release();
-    }
-#endif
-
-protected:
-    void flatten(SkWriteBuffer&) const override;
-
-    sk_sp<SkSpecialImage> onFilterImage(SkSpecialImage* source, const Context&,
-                                        SkIPoint* offset) const override;
-
-private:
-    SkDownSampleImageFilter(SkScalar scale, sk_sp<SkImageFilter> input)
-        : INHERITED(&input, 1, nullptr), fScale(scale) {}
-
-    SkScalar fScale;
-
-    typedef SkImageFilter INHERITED;
-};
-
-#endif