Add a simple compositor for Sky

sky/compositor/layer_host.h

Index: sky/compositor/layer_host.h
diff --git a/sky/compositor/layer_host.h b/sky/compositor/layer_host.h
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index 0000000000000000000000000000000000000000..d559cdfaba0f568bfb2a83d0dc91b285ed7a98e7
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+++ b/sky/compositor/layer_host.h
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+// Copyright 2014 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_LAYER_HOST_H_
+#define SKY_COMPOSITOR_LAYER_HOST_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "mojo/skia/ganesh_context.h"
+#include "sky/compositor/layer_host_client.h"
+#include "sky/compositor/resource_manager.h"
+#include "sky/compositor/surface_holder.h"
+
+namespace sky {
+class ResourceManager;
+class Layer;
+class LayerHostClient;
+
+class LayerHost : public SurfaceHolder::Client {
+ public:
+  explicit LayerHost(LayerHostClient* client);
+  ~LayerHost();
+
+  LayerHostClient* client() const { return client_; }
+
+  const base::WeakPtr<mojo::GLContext>& gl_context() const {
+    return gl_context_;
+  }
+
+  mojo::GaneshContext* ganesh_context() const {
+    return const_cast<mojo::GaneshContext*>(&ganesh_context_);
+  }
+
+  ResourceManager* resource_manager() const {
+    return const_cast<ResourceManager*>(&resource_manager_);
+  }
+
+  void SetNeedsAnimate();
+  void SetRootLayer(scoped_refptr<Layer> layer);
+
+ private:
+  // SurfaceHolder::Client
+  void OnReadyForNextFrame() override;
+  void OnSurfaceIdAvailable(mojo::SurfaceIdPtr surface_id) override;
+  void ReturnResources(
+      mojo::Array<mojo::ReturnedResourcePtr> resources) override;
+
+  void Upload(Layer* layer);
+
+  LayerHostClient* client_;
+  SurfaceHolder surface_holder_;
+  base::WeakPtr<mojo::GLContext> gl_context_;
+  mojo::GaneshContext ganesh_context_;
+  ResourceManager resource_manager_;
+
+  scoped_refptr<Layer> root_layer_;
+
+  DISALLOW_COPY_AND_ASSIGN(LayerHost);
+};
+
+}  // namespace sky
+
+#endif  // SKY_COMPOSITOR_LAYER_HOST_H_