Add a SharedMemSynchronizer class.

media/media.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
     # Override to dynamically link the PulseAudio library.
     'use_pulseaudio%': 0,
     # Override to dynamically link the cras (ChromeOS audio) library.
@@ skipping 37 matching lines @@
         'audio/audio_output_proxy.cc',
         'audio/audio_output_proxy.h',
         'audio/audio_parameters.cc',
         'audio/audio_parameters.h',
         'audio/audio_util.cc',
         'audio/audio_util.h',
         'audio/android/audio_manager_android.cc',
         'audio/android/audio_manager_android.h',
         'audio/android/audio_track_output_android.cc',
         'audio/android/audio_track_output_android.h',
+        'audio/cross_process_notification.cc',
+        'audio/cross_process_notification.h',
+        'audio/cross_process_notification_win.cc',
+        'audio/cross_process_notification_posix.cc',
         'audio/fake_audio_input_stream.cc',
         'audio/fake_audio_input_stream.h',
         'audio/fake_audio_output_stream.cc',
         'audio/fake_audio_output_stream.h',
         'audio/linux/audio_manager_linux.cc',
         'audio/linux/audio_manager_linux.h',
         'audio/linux/alsa_input.cc',
         'audio/linux/alsa_input.h',
         'audio/linux/alsa_output.cc',
         'audio/linux/alsa_output.h',
@@ skipping 542 matching lines @@
       'sources': [
         'audio/audio_input_controller_unittest.cc',
         'audio/audio_input_device_unittest.cc',
         'audio/audio_input_unittest.cc',
         'audio/audio_input_volume_unittest.cc',
         'audio/audio_low_latency_input_output_unittest.cc',
         'audio/audio_output_controller_unittest.cc',
         'audio/audio_output_proxy_unittest.cc',
         'audio/audio_parameters_unittest.cc',
         'audio/audio_util_unittest.cc',
+        'audio/cross_process_notification_unittest.cc',
         'audio/linux/alsa_output_unittest.cc',
         'audio/mac/audio_low_latency_input_mac_unittest.cc',
         'audio/mac/audio_output_mac_unittest.cc',
         'audio/simple_sources_unittest.cc',
         'audio/win/audio_low_latency_input_win_unittest.cc',
         'audio/win/audio_low_latency_output_win_unittest.cc',
         'audio/win/audio_output_win_unittest.cc',
         'base/buffers_unittest.cc',
         'base/clock_unittest.cc',
         'base/composite_filter_unittest.cc',
@@ skipping 366 matching lines @@
             '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
           ],
           'sources': [
             'tools/media_bench/media_bench.cc',
           ],
         },
       ],
     }]
   ],
 }