Only 3 callers are using a non-UTF-8 charset as the first parameter. * MediaDocument.cpp: This does not make sense because the "filename" part of URLs will always be encoded with UTF-8. * nsContextMenu.js: This is wrong because "mailto:" URLs don't care about the document charset. * Finder.jsm: This caused bug 1623222. Differential Revision: https://phabricator.services.mozilla.com/D67386