mediaplayer: check existence of AudioTrack before trying to access it.

}

bool NuPlayer::Renderer::onDrainAudioQueue() {

#if 0

    // TODO: This call to getPosition checks if AudioTrack has been created

    // in AudioSink before draining audio. If AudioTrack doesn't exist, then

    // CHECKs on getPosition will fail.

    // We still need to figure out why AudioTrack is not created when

    // this function is called. One possible reason could be leftover

    // audio. Another possible place is to check whether decoder

    // has received INFO_FORMAT_CHANGED as the first buffer since

    // AudioSink is opened there, and possible interactions with flush

    // immediately after start. Investigate error message

    // "vorbis_dsp_synthesis returned -135", along with RTSP.

    uint32_t numFramesPlayed;

    if (mAudioSink->getPosition(&numFramesPlayed) != OK) {

        return false;

    }

#if 0

    ssize_t numFramesAvailableToWrite =

        mAudioSink->frameCount() - (mNumFramesWritten - numFramesPlayed);