Adapt find-in-code to use the new Finder.jsm style interface to the find...

... toolbar.

Jason, these are the changes necessary to make Stylish work with the findbar in Fx 27.
I haven't tested it in action, because I don't know how you roll this source into a working add-on. But it *should* work. :tongue: 

If you have any questions, please let me know!

Reference bug: https://bugzilla.mozilla.org/show_bug.cgi?id=939381