void RenderThreadImpl::RegisterSchemes() {
  WebString swappedout_scheme(base::ASCIIToUTF16(kSwappedOutScheme));
  WebSecurityPolicy::registerURLSchemeAsDisplayIsolated(swappedout_scheme);
  WebSecurityPolicy::registerURLSchemeAsEmptyDocument(swappedout_scheme);
}

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.