Merge "AudioTrack: fix unwanted underrun when restarting" into klp-dev

    if (previousState == STATE_STOPPED || previousState == STATE_FLUSHED) {

        // reset current position as seen by client to 0

        mProxy->setEpoch(mProxy->getEpoch() - mProxy->getPosition());

        // force refresh of remaining frames by processAudioBuffer() as last

        // write before stop could be partial.

        mRefreshRemaining = true;

    }

    mNewPosition = mProxy->getPosition() + mUpdatePeriod;

    int32_t flags = android_atomic_and(~CBLK_DISABLED, &mCblk->mFlags);