message: Fixed fallback code that optionally created EigenThreadPoolWrapper.
diff: @@ -100,10 +100,14 @@ struct LocalDevice::EigenThreadPoolInfo {
  Eigen::ThreadPoolInterface* threadpool =
  eigen_worker_threads_.workers->AsEigenThreadPool();
  if (threadpool == nullptr) {
  + // This fallback code path is not executed since ThreadPool's current
  + // implementation of AsEigenThreadPool() always returns a non-null
  + // pointer.
  eigen_threadpool_wrapper_ = absl::make_unique<EigenThreadPoolWrapper>(
  eigen_worker_threads_.workers);
  + threadpool = eigen_threadpool_wrapper_.get();
  }
  - if (allocator) {
  + if (allocator != nullptr) {
  eigen_allocator_.reset(new EigenAllocator(allocator));
  }
  eigen_device_.reset(new Eigen::ThreadPoolDevice(
  