Remove unused AudioBuffersState member.

media/audio/audio_buffers_state.cc

 // Copyright (c) 2010 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.
 
 #include "media/audio/audio_buffers_state.h"
 
 AudioBuffersState::AudioBuffersState()
     : pending_bytes(0),
-      hardware_delay_bytes(0),
-      timestamp(base::Time::Now()) {
+      hardware_delay_bytes(0) {
 }
 
 AudioBuffersState::AudioBuffersState(int pending_bytes,
                                      int hardware_delay_bytes)
     : pending_bytes(pending_bytes),
-      hardware_delay_bytes(hardware_delay_bytes),
-      timestamp(base::Time::Now()) {
+      hardware_delay_bytes(hardware_delay_bytes) {
 }
-
-int AudioBuffersState::total_bytes() {
-  return pending_bytes + hardware_delay_bytes;
-}