This extension can switch the user agent of a browser. and it allows you to find all HTTP URLs.

Most web pages are fully and completely compatible with Chrome. 
However, there are some sites that insist upon using a different browser. 
So, an extension has been developed for Chrome called the Ultimate User Agent Switcher.

When a web page suggests using a different browser or upgrading the current one, 
the Ultimate User Agent Switcher tricks the web site into believing that it is a different browser, often allowing access.

And this extension allows you to find all HTTP URLs. (URL sniffer feature)
This extension supports Chrome 18 and later.

*Enable,disable switcher
*Add,edit User Agent list
*Filters to apply
*URL pattern to apply
*View URL sniffer log (type,method,URL,original HTTP headers..)
*Export/Import settings
*Various options

http://iblogbox.com/chrome/useragent"