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

media/audio/shared_memory_util.h

-// 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.
-
-#ifndef MEDIA_AUDIO_SHARED_MEMORY_UTIL_H_
-#define MEDIA_AUDIO_SHARED_MEMORY_UTIL_H_
-
-#include "base/basictypes.h"
-#include "base/memory/shared_memory.h"
-#include "media/base/media_export.h"
-
-namespace media {
-
-// Value sent by the controller to the renderer in low-latency mode
-// indicating that the stream is paused.
-enum { kPauseMark = -1 };
-
-// Functions that handle data buffer passed between processes in the shared
-// memory.  Called on both IPC sides.  These are necessary because the shared
-// memory has a layout: the last word in the block is the data size in bytes.
-
-MEDIA_EXPORT uint32 TotalSharedMemorySizeInBytes(uint32 packet_size);
-MEDIA_EXPORT uint32 PacketSizeInBytes(uint32 shared_memory_created_size);
-MEDIA_EXPORT uint32 GetActualDataSizeInBytes(base::SharedMemory* shared_memory,
-                                             uint32 packet_size);
-MEDIA_EXPORT void SetActualDataSizeInBytes(base::SharedMemory* shared_memory,
-                                           uint32 packet_size,
-                                           uint32 actual_data_size);
-MEDIA_EXPORT void SetActualDataSizeInBytes(void* shared_memory_ptr,
-                                           uint32 packet_size,
-                                           uint32 actual_data_size);
-MEDIA_EXPORT void SetUnknownDataSize(base::SharedMemory* shared_memory,
-                                     uint32 packet_size);
-MEDIA_EXPORT bool IsUnknownDataSize(base::SharedMemory* shared_memory,
-                                    uint32 packet_size);
-
-}  // namespace media
-
-#endif  // MEDIA_AUDIO_SHARED_MEMORY_UTIL_H_