  RenderViewZoomer(const std::string& scheme,
                   const std::string& host,
                   double zoom_level) : scheme_(scheme),
                                        host_(host),
                                        zoom_level_(zoom_level) {
  }

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.