Delete IPC::ChannelPosix, IPC::ChannelWin and IPC::AttachmentBroker.

ipc/brokerable_attachment_mac.cc

-// 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.
-
-#include "ipc/brokerable_attachment.h"
-
-#include "crypto/random.h"
-
-namespace IPC {
-
-// static
-BrokerableAttachment::AttachmentId
-BrokerableAttachment::AttachmentId::CreateIdWithRandomNonce() {
-  AttachmentId id;
-  // In order to prevent mutually untrusted processes from stealing resources
-  // from one another, the nonce must be secret. This generates a 128-bit,
-  // cryptographicaly-strong random number.
-  crypto::RandBytes(id.nonce, BrokerableAttachment::kNonceSize);
-  return id;
-}
-
-}  // namespace IPC