Remove unused AudioBuffersState member.

content/common/media/audio_messages.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.
 
 // IPC messages for the audio.
 // Multiply-included message file, hence no include guard.
 
 #include "base/basictypes.h"
 #include "base/shared_memory.h"
 #include "base/sync_socket.h"
 #include "content/common/content_export.h"
 #include "content/common/media/audio_stream_state.h"
 #include "ipc/ipc_message_macros.h"
 #include "media/audio/audio_buffers_state.h"
 #include "media/audio/audio_parameters.h"
 
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 #define IPC_MESSAGE_START AudioMsgStart
 
 IPC_ENUM_TRAITS(AudioStreamState)
 IPC_ENUM_TRAITS(AudioParameters::Format)
 IPC_ENUM_TRAITS(ChannelLayout)
 
 IPC_STRUCT_TRAITS_BEGIN(AudioBuffersState)
   IPC_STRUCT_TRAITS_MEMBER(pending_bytes)
   IPC_STRUCT_TRAITS_MEMBER(hardware_delay_bytes)
-  IPC_STRUCT_TRAITS_MEMBER(timestamp)
 IPC_STRUCT_TRAITS_END()
 
 IPC_STRUCT_TRAITS_BEGIN(AudioParameters)
   IPC_STRUCT_TRAITS_MEMBER(format)
   IPC_STRUCT_TRAITS_MEMBER(channel_layout)
   IPC_STRUCT_TRAITS_MEMBER(sample_rate)
   IPC_STRUCT_TRAITS_MEMBER(bits_per_sample)
   IPC_STRUCT_TRAITS_MEMBER(samples_per_packet)
   IPC_STRUCT_TRAITS_MEMBER(channels)
 IPC_STRUCT_TRAITS_END()
@@ skipping 106 matching lines @@
 // Set audio volume of the input stream specified by stream_id.
 IPC_MESSAGE_CONTROL2(AudioInputHostMsg_SetVolume,
                      int /* stream_id */,
                      double /* volume */)
 
 // Start the device referenced by the session_id for the input stream specified
 // by stream_id.
 IPC_MESSAGE_CONTROL2(AudioInputHostMsg_StartDevice,
                      int /* stream_id */,
                      int /* session_id */)