That is from the so-called "White Horse" prophecy which while parts of it seem to fit with either words of other apostles or with circumstances, it's validity has not been solidly confirmed.Didn't Joseph Smith once make a prophecy that if the American people didn't repent, one day they will find the "heathen Chinese" invading their west coast? Or something like that.
You can find the full text and analysis in "Prophecy: Key to the Future" by Duane S. Crowther. (Appendix)