ipc: Remove unnecessary attachment broker plumbing.

remoting/host/desktop_session_proxy.cc

 // Copyright (c) 2012 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 "remoting/host/desktop_session_proxy.h"
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/process/process_handle.h"
 #include "base/memory/shared_memory.h"
@@ skipping 247 matching lines @@
   DCHECK(desktop_pipe.auto_close);
 
   IPC::ChannelHandle desktop_channel_handle(std::string(), desktop_pipe);
 
 #else
 #error Unsupported platform.
 #endif
 
   // Connect to the desktop process.
   desktop_channel_ = IPC::ChannelProxy::Create(desktop_channel_handle,
-                                               IPC::Channel::MODE_CLIENT,
-                                               this,
-                                               io_task_runner_.get(),
-                                               nullptr);
+                                               IPC::Channel::MODE_CLIENT, this,
+                                               io_task_runner_.get());
 
   // Pass ID of the client (which is authenticated at this point) to the desktop
   // session agent and start the agent.
   SendToDesktop(new ChromotingNetworkDesktopMsg_StartSessionAgent(
       client_session_control_->client_jid(),
       screen_resolution_,
       virtual_terminal_));
 
   return true;
 }
@@ skipping 298 matching lines @@
 }
 
 // static
 void DesktopSessionProxyTraits::Destruct(
     const DesktopSessionProxy* desktop_session_proxy) {
   desktop_session_proxy->caller_task_runner_->DeleteSoon(FROM_HERE,
                                                          desktop_session_proxy);
 }
 
 }  // namespace remoting