Fold //ipc/mojo into //ipc.

ipc/mojo/ipc_mojo_handle_attachment.h

-// Copyright (c) 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 IPC_MOJO_IPC_MOJO_HANDLE_ATTACHMENT_H_
-#define IPC_MOJO_IPC_MOJO_HANDLE_ATTACHMENT_H_
-
-#include "base/files/file.h"
-#include "base/macros.h"
-#include "build/build_config.h"
-#include "ipc/ipc_export.h"
-#include "ipc/ipc_message_attachment.h"
-#include "mojo/public/cpp/system/handle.h"
-
-namespace IPC {
-
-namespace internal {
-
-// A MessageAttachment that holds a MojoHandle.
-// This can hold any type of transferrable Mojo handle (i.e. message pipe, data
-// pipe, etc), but the receiver is expected to know what type of handle to
-// expect.
-class IPC_MOJO_EXPORT MojoHandleAttachment : public MessageAttachment {
- public:
-  explicit MojoHandleAttachment(mojo::ScopedHandle handle);
-
-  Type GetType() const override;
-
-#if defined(OS_POSIX)
-  // Should not be called.
-  base::PlatformFile TakePlatformFile() override;
-#endif  // OS_POSIX
-
-  // Returns the owning handle transferring the ownership.
-  mojo::ScopedHandle TakeHandle();
-
- private:
-  ~MojoHandleAttachment() override;
-  mojo::ScopedHandle handle_;
-
-  DISALLOW_COPY_AND_ASSIGN(MojoHandleAttachment);
-};
-
-}  // namespace internal
-}  // namespace IPC
-
-#endif  // IPC_MOJO_IPC_MOJO_HANDLE_ATTACHMENT_H_