I had the same issue on OSX Mavericks, it turned out that Sophos anti-virus was blocking certain requests, once I uninstalled it the issue went away.
If you think that it might be caused by an extension one easy way to try and test this is to open chrome with the '--disable-extensions
flag to see if it fixes the problem. If that doesn't fix it consider looking beyond the browser to see if any other application might be causing the problem, specifically security apps which can affect requests.