Use a direct include of the message_loop header in remoting/.

remoting/host/pairing_registry_delegate_linux_unittest.cc

 // Copyright 2013 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/pairing_registry_delegate_linux.h"
 
 #include "base/file_util.h"
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/task_runner.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/timer/timer.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace remoting {
 
 using protocol::PairingRegistry;
 
@@ skipping 48 matching lines @@
                  base::Unretained(this),
                  load_delegate.get(),
                  test_data));
 
   run_loop.Run();
 
   base::DeleteFile(temp_dir, true);
 };
 
 }  // namespace remoting