Switch audio synchronization from sleep() based to select() based.

media/shared_memory_support.gypi

 # 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,
     # These are defined here because we need to build this library both for
     # the general media pipeline and again for the untrusted NaCl target.
     'shared_memory_support_sources': [
       'audio/audio_parameters.cc',
       'audio/audio_parameters.h',
-      'audio/shared_memory_util.cc',
-      'audio/shared_memory_util.h',
       'base/audio_bus.cc',
       'base/audio_bus.h',
       'base/channel_layout.cc',
       'base/channel_layout.h',
       'base/limits.h',
       'base/media_export.h',
       'base/vector_math.cc',
       'base/vector_math.h',
     ],
   },
 }