A browser inside Emacs: do you agree that this would only make sense if all text editing was governed by Emacs, i.e. each text area was handled by Emacs directly as a buffer?
(Is that doable with the new Gecko library?)
It would make the most sense to have the text areas in gecko governed
by Emacs. It does complicate things, however; I don't think libxul
provides that level of transparency into what it renders, though I am
quite ignorant of both libxul and Emacs at the C level. Of course, if
libxul offered the same plugin architecture that Firefox does, then a
plugin like It's All Text could be used to call emacsclient when
editting text areas. Seems a bit like the snake eating its tail, but
it may be a reasonable first cut at the concept.
In that case, why not have an extra port of Emacs that would provide a "text area widget" (and maybe more) to be used as library by other applications written in GTK/GNUStep/Cocoa/whatever frameworks?
This is a possibilty - my focus was less on Emacs as a text editor, and more on the buffer management, search, window configurations (C-x r w) and kill ring sharing that embedding would offer. Of course, being able to edit text areas in Emacs would be icing on the cake.