Improve handling of invalid command line in Me2Me host.

remoting/host/remoting_me2me_host.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.
 //
 // This file implements a standalone host process for Me2Me.
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <string>
@@ skipping 846 matching lines @@
   context_->network_task_runner()->PostTask(
       FROM_HERE,
       base::Bind(&HostProcess::ShutdownHost, this, kSuccessExitCode));
 }
 
 void HostProcess::StartOnUiThread() {
   DCHECK(context_->ui_task_runner()->BelongsToCurrentThread());
 
   if (!InitWithCommandLine(base::CommandLine::ForCurrentProcess())) {
     // Shutdown the host if the command line is invalid.
-    context_->network_task_runner()->PostTask(
-        FROM_HERE, base::Bind(&HostProcess::ShutdownHost, this,
-                              kUsageExitCode));
+    ShutdownOnUiThread();
     return;
   }
 
   policy_watcher_ =
       PolicyWatcher::Create(nullptr, context_->file_task_runner());
   policy_watcher_->StartWatching(
       base::Bind(&HostProcess::OnPolicyUpdate, base::Unretained(this)),
       base::Bind(&HostProcess::OnPolicyError, base::Unretained(this)));
 
 #if defined(OS_LINUX)
@@ skipping 861 matching lines @@
       base::TimeDelta::FromSeconds(kShutdownTimeoutSeconds));
   new HostProcess(std::move(context), &exit_code, &shutdown_watchdog);
 
   // Run the main (also UI) message loop until the host no longer needs it.
   message_loop.Run();
 
   return exit_code;
 }
 
 }  // namespace remoting