The following was removed:
- the main meat of the overlays and interface in XULDocument
- all overlay observers and forward references
- the notion of a master document
- XUL overlay provider
- manifest parsing of overlay attribute
- references to "overlay" atom
- restrictions on persistence (only need because of overlays)
- unused code that the above referenced
I also attempted to update comments that referenced overlays, but there is still
some work to be done here.
MozReview-Commit-ID: 8lrirzcgSuJ
--HG--
extra : rebase_source : 25b4e1d3fb2af6f02d894887271fd345c9c2083b