Again, amazingly enough, the Chrome dragon is pretty simple to breed. (I guess between Sun, Moon and Rainbow dragons, which are still elusive to many players, the Dragonvale creators took it easy on us this time.)
Metal Dragon + Air Dragon = Chrome Dragon
And yes that tiny little dragon behind the Metal dragon is the Chrome Dragon lol.
If you want to add me in the game my gamecenter name is prplrush. Feel free to follow my blog for more updates via google friend connect. (right below this post) and google + this post