I am looking for source code or library to expose Unix Domain Sockets to my Google Chrome's extension via NPAPI.
Does anything similar or related already exist?
Creating something like that generically would be exceptionally dangerous; you could, however, use FireBreath to create a plugin that would do that and it would be prettye easy. Make sure, though, that you are very careful with the security model since if you can instantiate it on your page someone else can on their page too, and they can then use it maliciously.