void HTMLMediaElement::LoadNextSourceChild() {
  String content_type;
  KURL media_url = SelectNextSourceChild(&content_type, kComplain);
  if (!media_url.IsValid()) {
    WaitForSourceChange();
    return;
  }

  ResetMediaPlayerAndMediaSource();

  load_state_ = kLoadingFromSourceElement;
  LoadResource(WebMediaPlayerSource(WebURL(media_url)), content_type);
}

Unknown