Delete unneeded includes of deprecated system_wrappers include files.

webrtc/modules/audio_device/linux/audio_mixer_manager_pulse_linux.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_AUDIO_DEVICE_AUDIO_MIXER_MANAGER_PULSE_LINUX_H
 #define WEBRTC_AUDIO_DEVICE_AUDIO_MIXER_MANAGER_PULSE_LINUX_H
 
 #include "webrtc/modules/audio_device/include/audio_device.h"
 #include "webrtc/modules/audio_device/linux/pulseaudiosymboltable_linux.h"
-#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
 #include "webrtc/typedefs.h"
 #include "webrtc/base/thread_checker.h"
 
 #include <pulse/pulseaudio.h>
 #include <stdint.h>
 
 #ifndef UINT32_MAX
 #define UINT32_MAX  ((uint32_t)-1)
 #endif
 
@@ skipping 84 matching lines @@
     // Stores thread ID in constructor.
     // We can then use ThreadChecker::CalledOnValidThread() to ensure that
     // other methods are called from the same thread.
     // Currently only does RTC_DCHECK(thread_checker_.CalledOnValidThread()).
     rtc::ThreadChecker thread_checker_;
 };
 
 }
 
 #endif  // MODULES_AUDIO_DEVICE_MAIN_SOURCE_LINUX_AUDIO_MIXER_MANAGER_PULSE_LINUX_H_