South China Sea II

The problem for the US is when they see this:

http://news.xinhuanet.com/english/photo/2015-08/24/c_134548662.htm

Do the Chinese and Russians have in the small print of their mutual treaties a commitment to come to each other's aid if the US whack the other?

If they do, and they do, what is the US flotilla doing in the South China Sea?