As the global object of a context is rooted, if we want the GC to act on these objects we need to take them out of the globals. https://bugzilla.gnome.org/show_bug.cgi?id=678737
https://bugzilla.gnome.org/show_bug.cgi?id=678737
js2-mode is no longer developed and we recommend js-mode these days, so switch the modelines to specify that, and make them consistent across all files. https://bugzilla.gnome.org/show_bug.cgi?id=660358
https://bugzilla.gnome.org/show_bug.cgi?id=658092