bool RenderThreadImpl::ResolveProxy(const GURL& url, std::string* proxy_list) {
  bool result = false;
  Send(new ViewHostMsg_ResolveProxy(url, &result, proxy_list));
  return result;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.