Implement an SkPicture image filter source. This is required for the external-SVG reference feature…

include/effects/SkPictureSource.h

+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkPictureSource_DEFINED
+#define SkPictureSource_DEFINED
+
+#include "SkImageFilter.h"
+#include "SkPicture.h"
+
+class SK_API SkPictureSource : public SkImageFilter {

[reed1, 2013/12/12 19:31:53]

Name looks a little too general... how about SkPictureSourceImageFilter?

+public:
+    explicit SkPictureSource(const SkPicture& picture);

[reed1, 2013/12/12 19:31:53]

dox:
- do you 'ref' the picture argument?

I know we take a & in drawPicture, but I think that is a bug. Everywhere else we
pass around refcnt objects, we pass pointers. I think we should do that here as
well.

+    SkPictureSource(const SkPicture& picture, const SkRect& rect);

[reed1, 2013/12/12 19:31:53]

dox:
- is rect a crop rect, or is it resizing the picture to fit inside?

+
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkPictureSource)
+
+protected:
+    explicit SkPictureSource(SkFlattenableReadBuffer& buffer);
+    virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
+    virtual bool onFilterImage(Proxy*, const SkBitmap& src, const SkMatrix&,
+                               SkBitmap* result, SkIPoint* offset) SK_OVERRIDE;
+
+private:
+    SkPicture fPicture;
+    SkRect    fRect;
+    typedef SkImageFilter INHERITED;
+};
+
+#endif