Sky should use an SkPicture when drawing

sky/compositor/rasterizer_ganesh.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_COMPOSITOR_DISPLAY_RASTERIZER_GANESH_H_
+#define SKY_COMPOSITOR_DISPLAY_RASTERIZER_GANESH_H_
+
+#include "sky/compositor/rasterizer.h"
+
+namespace sky {
+class LayerHost;
+
+class RasterizerGanesh : public Rasterizer {
+ public:
+  explicit RasterizerGanesh(LayerHost* host);
+  ~RasterizerGanesh() override;
+
+  scoped_ptr<mojo::GLTexture> Rasterize(SkPicture* picture) override;
+
+ private:
+  LayerHost* host_;
+
+  DISALLOW_COPY_AND_ASSIGN(RasterizerGanesh);
+};
+
+}  // namespace sky
+
+#endif  // SKY_COMPOSITOR_DISPLAY_RASTERIZER_GANESH_H_