Make rendering use PaintingNodes for increased efficiency.

sky/engine/core/painting/PaintingNode.h

Index: sky/engine/core/painting/PaintingNode.h
diff --git a/sky/engine/core/painting/PaintingNode.h b/sky/engine/core/painting/PaintingNode.h
new file mode 100644
index 0000000000000000000000000000000000000000..5f0e25569cfa2e3bbde514a5a417e2e4612d0eda
--- /dev/null
+++ b/sky/engine/core/painting/PaintingNode.h
@@ -0,0 +1,56 @@
+// 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 : public SkDrawable {
+public:
+    static PassRefPtr<PaintingNodeDrawable> create(PassRefPtr<SkDrawable> skDrawable);
+    static PassRefPtr<PaintingNodeDrawable> create();
+
+    ~PaintingNodeDrawable() override {}
+
+    SkRect onGetBounds();
+    void onDraw(SkCanvas* canvas);
+    SkPicture* onNewPictureSnapshot();
+    void set_drawable(PassRefPtr<SkDrawable> drawable) { m_drawable = drawable; }
+
+private:
+    PaintingNodeDrawable();
+    explicit PaintingNodeDrawable(PassRefPtr<SkDrawable> skDrawable);
+    RefPtr<SkDrawable> m_drawable;
+};
+
+
+
+
+class PaintingNode : public RefCounted<PaintingNode>, public DartWrappable {
+    DEFINE_WRAPPERTYPEINFO();
+public:
+    static PassRefPtr<PaintingNode> create();
+    ~PaintingNode() override;
+
+    void setBackingDrawable(PassRefPtr<Drawable> drawable) {
+        m_paintingNodeDrawable->set_drawable(drawable->toSkia());
+    }
+    SkDrawable* toSkia() { return m_paintingNodeDrawable.get(); }
+
+private:
+    PaintingNode();
+    PassRefPtr<Picture> newPictureSnapshot();
+    RefPtr<PaintingNodeDrawable> m_paintingNodeDrawable;
+};
+
+} // namespace blink
+
+#endif  // SKY_ENGINE_CORE_PAINTING_PAINTINGNODE_H_