NightWatch sees China's partnership with the UAE as filling a void left by the U.S. :
China has maintained a strategic relationship with Saudi Arabia since before the first Gulf War. The closer relationship with the UAE signifies that China intends to be consequential in both Sunni Arab states as well as Shiite Iran.
A recent analysis concluded that Arab states friendly to the US now perceive that the will to use US influence in the Middle East is waning and thus have begun looking for other partners to help ensure their long term security. China is the obvious candidate and is showing that it is prepared to fill any power vacuum the US choses to leave.
Omri Ceren sees this as some kind of problem, but I'd argue it's a positive development. China is more dependent on Gulf oil than the U.S. (the short-sighted killing of the Keystone pipeline notwithstanding) and should therefore take on a larger share of the Gulf's security headaches.