Make rendering use PaintingNodes for increased efficiency.

sky/engine/core/painting/PaintingNode.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SKY_ENGINE_CORE_PAINTING_PAINTINGNODE_H_
+#define SKY_ENGINE_CORE_PAINTING_PAINTINGNODE_H_
+
+#include "sky/engine/core/painting/Drawable.h"
+#include "sky/engine/tonic/dart_wrappable.h"
+#include "sky/engine/wtf/PassRefPtr.h"
+#include "sky/engine/wtf/RefCounted.h"
+#include "third_party/skia/include/core/SkDrawable.h"
+
+namespace blink {
+
+class PaintingNodeDrawable;
+
+class PaintingNode : public RefCounted<PaintingNode>, public DartWrappable {
+    DEFINE_WRAPPERTYPEINFO();
+public:
+    static PassRefPtr<PaintingNode> create();
+    ~PaintingNode() override;
+
+    void setBackingDrawable(PassRefPtr<Drawable> drawable);
+    SkDrawable* toSkia();
+    PassRefPtr<Picture> newPictureSnapshot();
+
+private:
+    PaintingNode();
+    RefPtr<PaintingNodeDrawable> m_paintingNodeDrawable;
+};
+
+} // namespace blink
+
+#endif  // SKY_ENGINE_CORE_PAINTING_PAINTINGNODE_H_