Implement an SkPaint-based image filter

include/effects/SkPaintImageFilter.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkPaintImageFilter_DEFINED
+#define SkPaintImageFilter_DEFINED
+
+#include "SkImageFilter.h"
+#include "SkPaint.h"
+
+class SK_API SkPaintImageFilter : public SkImageFilter {
+public:
+    /** Create a new image filter which fills the given rectangle using the
+     *  given paint. If no rectangle is specified, an output is produced with
+     *  the same bounds as the input primitive (even though the input
+     *  primitive's pixels are not used for processing).
+     *  @param paint  Paint to use when filling the rect.
+     *  @param rect   Rectangle of output pixels. If NULL or a given crop edge is
+     *                not specified, the source primitive's bounds are used
+     *                instead.
+     */
+    static SkImageFilter* Create(const SkPaint& paint, const CropRect* rect = NULL);
+
+    bool canComputeFastBounds() const override;
+
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkPaintImageFilter)
+
+protected:
+    void flatten(SkWriteBuffer&) const override;
+    bool onFilterImage(Proxy*, const SkBitmap& src, const Context&, SkBitmap* result,
+                       SkIPoint* loc) const override;
+
+private:
+    SkPaintImageFilter(const SkPaint& paint, const CropRect* rect);
+
+    SkPaint fPaint;
+
+    typedef SkImageFilter INHERITED;
+};
+
+#endif