It's interesting. The address bar currently doubles as a search input, but doesn't autocomplete. The search bar does autocomplete, but won't take you to an address if you put one in it. (it takes you to a search for the address)

In my opinion, they need to think this through a bit more. Each input bar is crippled in some way (one won't autocomplete, the other won't go to addresses), and it's all driven by wanting to keep incomplete searches private (until Enter gets hit). Do users realize that the search bar in Firefox is not private, whereas the address bar is? I'm betting not. Do users expect them to be? Chrome assumes not.

In my opinion, if the privacy thing is so important, they'd still be better off having just one input with autocomplete off by default, and easily toggled to on. I doubt that users understand the current setup as "address bar is private, search bar is not".