Teach SkyShell how to draw with Ganesh

sky/shell/gpu/rasterizer.h

Index: sky/shell/gpu/rasterizer.h
diff --git a/sky/shell/gpu/rasterizer.h b/sky/shell/gpu/rasterizer.h
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+// 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_SHELL_GPU_RASTERIZER_H_
+#define SKY_SHELL_GPU_RASTERIZER_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "skia/ext/refptr.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/gfx/native_widget_types.h"
+
+class SkPicture;
+
+namespace gfx {
+class GLContext;
+class GLShareGroup;
+class GLSurface;
+}
+
+namespace sky {
+namespace shell {
+class GaneshContext;
+class GaneshSurface;
+
+class Rasterizer {
+ public:
+  explicit Rasterizer();
+  ~Rasterizer();
+
+  base::WeakPtr<Rasterizer> GetWeakPtr();
+
+  void Init(gfx::AcceleratedWidget widget);
+  void Draw(skia::RefPtr<SkPicture> picture);
+
+ private:
+  bool CreateGLContext();
+  void EnsureGaneshSurface(const gfx::Size& size);
+
+  scoped_refptr<gfx::GLShareGroup> share_group_;
+  scoped_refptr<gfx::GLSurface> surface_;
+  scoped_refptr<gfx::GLContext> context_;
+
+  scoped_ptr<GaneshContext> ganesh_context_;
+  scoped_ptr<GaneshSurface> ganesh_surface_;
+
+  base::WeakPtrFactory<Rasterizer> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(Rasterizer);
+};
+
+}  // namespace shell
+}  // namespace sky
+
+#endif  // SKY_SHELL_GPU_RASTERIZER_H_