I would ask, even if Chinese companies did control Bitcoin, what is the point? They can not derive unnatural profits, any attempt to do so would only devalue bitcoin and the possibility of making profits..
They might be bribed to destroy the bitcoin if the incentive is good enough. It is my main concern of the concentration of mining in China.
I heard that the Bitmain is developing a second pool at the moment. That will attract more mining operations there.