How to disable XPConnect URI Check?

[Eric Murphy]

I want to change my all.js (or security-prefs.js) file so I can use 
XPConnect for file or http the same as chrome. How do I do this?

I see a pref("security.checkloaduri", true);, and I changed to false 
with no success. Also adding pref("security.checkxpconnect",false) does 
not seem to help either.

Thanks!
Eric