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

ipc/brokerable_attachment_mac.cc

Index: ipc/brokerable_attachment_mac.cc
diff --git a/ipc/brokerable_attachment_mac.cc b/ipc/brokerable_attachment_mac.cc
deleted file mode 100644
index dbcd86b361e3bb3d455eef9fe372587bfd4402c4..0000000000000000000000000000000000000000
--- a/ipc/brokerable_attachment_mac.cc
+++ /dev/null
@@ -1,22 +0,0 @@
-// 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