Revert of Remove IPC::BrokerableAttachment.

ipc/ipc_mojo_message_helper.cc

 // 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.
 
 #include "ipc/ipc_mojo_message_helper.h"
 
 #include <utility>
 
 #include "ipc/ipc_mojo_handle_attachment.h"
 
@@ skipping 14 matching lines @@
     base::PickleIterator* iter,
     mojo::ScopedMessagePipeHandle* handle) {
   scoped_refptr<base::Pickle::Attachment> attachment;
   if (!message->ReadAttachment(iter, &attachment)) {
     LOG(ERROR) << "Failed to read attachment for message pipe.";
     return false;
   }
 
   MessageAttachment::Type type =
       static_cast<MessageAttachment*>(attachment.get())->GetType();
-  if (type != MessageAttachment::Type::MOJO_HANDLE) {
+  if (type != MessageAttachment::TYPE_MOJO_HANDLE) {
     LOG(ERROR) << "Unxpected attachment type:" << type;
     return false;
   }
 
   handle->reset(mojo::MessagePipeHandle(
       static_cast<internal::MojoHandleAttachment*>(attachment.get())
           ->TakeHandle()
           .release()
           .value()));
   return true;
 }
 
 MojoMessageHelper::MojoMessageHelper() {
 }
 
 }  // namespace IPC