It's trending purple, just like some of the other suburban parts of the country that were once solidly red.
https://www.wsj.com/articles/is-orange-the-new-blue-for-southern-california-republican-stronghold-1519560002
If you don't have the paywall, last 20 years white demographic is down latino and asian are up. Republican registration has trended generally downward, democratic slightly upward, independents surge.
The fact that Royce and Issa are retiring is telling, too.