mus: Split the gpu client-lib into a separate component.

services/ui/public/cpp/mojo_buffer_backing.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 SERVICES_UI_PUBLIC_CPP_MOJO_BUFFER_BACKING_H_
-#define SERVICES_UI_PUBLIC_CPP_MOJO_BUFFER_BACKING_H_
-
-#include <stddef.h>
-
-#include <memory>
-
-#include "base/macros.h"
-#include "gpu/command_buffer/common/buffer.h"
-#include "mojo/public/cpp/system/core.h"
-
-namespace ui {
-
-class MojoBufferBacking : public gpu::BufferBacking {
- public:
-  MojoBufferBacking(mojo::ScopedSharedBufferMapping mapping, size_t size);
-  ~MojoBufferBacking() override;
-
-  static std::unique_ptr<gpu::BufferBacking> Create(
-      mojo::ScopedSharedBufferHandle handle,
-      size_t size);
-
-  void* GetMemory() const override;
-  size_t GetSize() const override;
-
- private:
-  mojo::ScopedSharedBufferMapping mapping_;
-  size_t size_;
-
-  DISALLOW_COPY_AND_ASSIGN(MojoBufferBacking);
-};
-
-}  // namespace ui
-
-#endif  // SERVICES_UI_PUBLIC_CPP_MOJO_BUFFER_BACKING_H_