According to the data gp linked, Irvine and Davis are 16% and 27% white. If you were assuming all non-whites at Irvine or Davis were not American, let this be a teachable moment.
Perhaps you're right. I haven't visited either in years! When I was there last, UC Irvine had the most ethnic Asian students, but they were mostly Americans. That may have changed.
Campus-wise, my anecdotal observation would be Irvine or Davis has most of international students by percentage, though.