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

media/audio/pulse/pulse_output.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 "media/audio/pulse/pulse_output.h"
 
 #include <pulse/pulseaudio.h>
 
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "media/audio/audio_manager_base.h"
 #include "media/audio/audio_parameters.h"
 #include "media/audio/pulse/pulse_util.h"
 
 namespace media {
 
 using pulse::AutoPulseLock;
 using pulse::WaitForOperationCompletion;
 
 // static, pa_stream_notify_cb
@@ skipping 187 matching lines @@
   volume_ = static_cast<float>(volume);
 }
 
 void PulseAudioOutputStream::GetVolume(double* volume) {
   DCHECK(manager_->GetMessageLoop()->BelongsToCurrentThread());
 
   *volume = volume_;
 }
 
 }  // namespace media