Iran is in Russia's pocket. Will China risk antagonizing them? It's in Russia best interest to keep the middle east destabilized as oil prices are important to their economy.
I don’t know if it would antagonize Russia. China buys a lot more middle eastern oil than we do. They also buy from Russia. From Russia and China’s perspective it may be good business. China is building a navy and they have a strategic interest in middle eastern stability to keep oil markets stable. I wouldn’t be surprised if they do take an active role in the middle east.