Assume pending buffered bytes is zero when ALSA has underrun.

media/audio/linux/alsa_wrapper.cc

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// 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/linux/alsa_wrapper.h"
 
 #include <alsa/asoundlib.h>
 
 AlsaWrapper::AlsaWrapper() {
 }
 
@@ skipping 52 matching lines @@
                               unsigned int rate, int soft_resample,
                               unsigned int latency) {
   return snd_pcm_set_params(handle, format, access, channels, rate,
                             soft_resample, latency);
 }
 
 snd_pcm_sframes_t AlsaWrapper::PcmAvailUpdate(snd_pcm_t* handle) {
   return snd_pcm_avail_update(handle);
 }
 
+snd_pcm_state_t AlsaWrapper::PcmState(snd_pcm_t* handle) {
+  return snd_pcm_state(handle);
+}
+
 const char* AlsaWrapper::StrError(int errnum) {
   return snd_strerror(errnum);
 }