Add a simple compositor for Sky

sky/compositor/layer_host_client.h

+// 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_CLIENT_H_
+#define SKY_COMPOSITOR_LAYER_HOST_CLIENT_H_
+
+#include "mojo/services/public/interfaces/surfaces/surface_id.mojom.h"
+
+namespace mojo {
+class Shell;
+}
+
+namespace sky {
+
+class LayerHostClient {
+ public:
+  virtual mojo::Shell* GetShell() = 0;
+  virtual void BeginFrame() = 0;
+  virtual void OnSurfaceIdAvailable(mojo::SurfaceIdPtr surface_id) = 0;
+
+ protected:
+  virtual ~LayerHostClient();
+};
+
+}  // namespace sky
+
+#endif  // SKY_COMPOSITOR_LAYER_HOST_CLIENT_H_