Haixia,
I work on the Google Code team. The short answer to your question is yes, that feature is no longer supported. Google Code Search only works for projects that host their source on Google Code, though we setup a special pipeline for Chromium. (
http://cs.chromium.org)
I, along with a couple of other developers, are working on updating the public Google Code Search instance. Hopefully, soon we can have an update-to-date Chromium index with Grok (
http://www.youtube.com/watch?v=KTJs-0EInW8) integration available for you on Google Code. Shortly after that will continue adding other special corpora like chromium-os.
If you would like some more information, please contact me privately. This is something we are actively working on.
Cheers,
-Chris