Both. Apple earns a lot of money in China, so they want to be seen as doing something with that in China to look better with the government + its already been taxed there anyways.

Same with most tech companies actually, just that Apple does very little R&D in China ATM, so investment it is.

The linked article claims that Tim Cook is meeting with Chinese propaganda officials. My bet is that Apple will first manufacture and sell electric cars in Asia than bring it to the USA. If that is true the ministry of propaganda is probably frustrated with Apple's secrecy. BTW, I doubt self-driving cars are very high on Apple's list. They are a very very practical company and self driving cars have not proven themselves yet.