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,
   },
@@ skipping 63 matching lines @@
         'audio/mac/audio_low_latency_input_mac.cc',
         'audio/mac/audio_low_latency_input_mac.h',
         'audio/mac/audio_low_latency_output_mac.cc',
         'audio/mac/audio_low_latency_output_mac.h',
         'audio/mac/audio_manager_mac.cc',
         'audio/mac/audio_manager_mac.h',
         'audio/mac/audio_output_mac.cc',
         'audio/mac/audio_output_mac.h',
         'audio/pulse/pulse_output.cc',
         'audio/pulse/pulse_output.h',
+        'audio/shared_mem_synchronizer.cc',
+        'audio/shared_mem_synchronizer.h',
+        'audio/shared_mem_synchronizer_win.cc',
+        'audio/shared_mem_synchronizer_posix.cc',
         'audio/simple_sources.cc',
         'audio/simple_sources.h',
         'audio/win/audio_low_latency_input_win.cc',
         'audio/win/audio_low_latency_input_win.h',
         'audio/win/audio_low_latency_output_win.cc',
         'audio/win/audio_low_latency_output_win.h',
         'audio/win/audio_manager_win.cc',
         'audio/win/audio_manager_win.h',
         'audio/win/avrt_wrapper_win.cc',
         'audio/win/avrt_wrapper_win.h',
@@ skipping 485 matching lines @@
         '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/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/shared_mem_synchronizer_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/clock_unittest.cc',
         'base/composite_filter_unittest.cc',
         'base/data_buffer_unittest.cc',
         'base/djb2_unittest.cc',
         'base/download_rate_monitor_unittest.cc',
         'base/filter_collection_unittest.cc',
         'base/h264_bitstream_converter_unittest.cc',
@@ skipping 349 matching lines @@
             '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
           ],
           'sources': [
             'tools/media_bench/media_bench.cc',
           ],
         },
       ],
     }]
   ],
 }