void ResourceDispatcherHostImpl::RemovePendingLoader(
    const LoaderMap::iterator& iter) {
  ResourceRequestInfoImpl* info = iter->second->GetRequestInfo();

  IncrementOutstandingRequestsMemory(-1, *info);

  pending_loaders_.erase(iter);
}

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.