I don't think that Europeans are able to conquer China. It is too big and unified for this. And I bit doubt that without WW1 Europeans would try conquer Middle East, speciality if OE doesn't collapse.
It was not unified during the 20's and 30's. It's not certain that this would happen without WWI, but I tend to think the pressure that the colonial powers put on China would only be greater without that conflict taking place. If they did, they could probably establish more direct control over large parts of China. It won't be an exclusively British or Japanese project, it will be divided up by something like the Berlin Conference.