If the Chinese miners were unified and collaborative in their approach, then they could theoretically gain control over the blockchain and thus Bitcoin.
However, in the real world what would probably happen is the core devs would code and release an update that would checkpoint the Chinese 'attack' and return control of the chain back to the economic majority (aka banks/coinbase/blockstream)
I don't quite understand what you mean by "economic majority"
Care to explain? Apart from that, we don't know how many Chinese miners the Chinese pools actually consist of. Some of them are obviously not mining pools but rather mining farms and those the Chinese government can indeed take control over. But if the pools are actually made up from many individual miners, these miners could potentially withdraw their mining resources from the pools, thereby essentially rendering them impotent. Personally, I'm more inclined to think that the rumors of the Chinese government preparing a 51% attack against Bitcoin network are just another round of FUD. At first, it was the Winklevoss FUD, then the BU FUD, and now the 51% attack FUD