The following is a list of the headers that cannot be overridden in Chrome browser tests:
- Authorization
- Cache-Control
- Connection
- Content-Length
- Host
- If-Modified-Since
- If-None-Match
- If-Range
- Partial-Data
- Pragma
- Proxy-Authorization
- Proxy-Connection
- Transfer-Encoding
*This list is not guaranteed to be complete nor stable. This is covered in more depth in the Chrome documentation: http://developer.chrome.com/trunk/extensions/webRequest.html