ipc: Create AttachmentBrokerPrivileged and AttachmentBrokerUnprivileged.

ipc/attachment_broker_unprivileged.cc

Index: ipc/attachment_broker_unprivileged.cc
diff --git a/ipc/ipc_handle_win.cc b/ipc/attachment_broker_unprivileged.cc
similarity index 53%
copy from ipc/ipc_handle_win.cc
copy to ipc/attachment_broker_unprivileged.cc
index da3b9bb6125dba3e65d0dcbf83902ee5248a5ffe..bc2eb5a764dbf0dfafa61ea5286bbc04d1b4bb70 100644
--- a/ipc/ipc_handle_win.cc
+++ b/ipc/attachment_broker_unprivileged.cc
@@ -2,14 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "ipc/ipc_handle_win.h"
+#include "ipc/attachment_broker_unprivileged.h"
 
 namespace IPC {
 
-HandleForTransit CreateHandleForTransit(HANDLE handle) {
-  HandleForTransit hft;
-  hft.handle = handle;
-  return hft;
-}
+AttachmentBrokerUnprivileged::AttachmentBrokerUnprivileged() {}
+
+AttachmentBrokerUnprivileged::~AttachmentBrokerUnprivileged() {}
 
 }  // namespace IPC