Moving "Open with" to the platform

[Federico Mena Quintero <federico ximian com>]

Hi,

Right now, the "Open with another application" dialog lives in
nautilus/libnautilus-private/nautilus-open-with-dialog.[ch].  This
dialog uses the machinery in GIO's GAppInfo to figure out which apps can
be used to open a file of a certain MIME-type.

There's a long-standing annoyance in Firefox, where it implements "open
with" by starting a file chooser in /usr/bin.  Now, if you complain
about the file chooser *right here* I will ignore your mail :)  My point
is that it would be nice if the "open with" GUI were available to all
apps, not just Nautilus.

We could do a few things:

* Move nautilus-open-with-dialog.[ch] into GTK+.  From a super-quick
read of the code, this uses no Nautilus-only stuff except for some of
libeel's convenience error dialogs, and some "the MIME info changed"
signal.

* Leave the dialog in place inside Nautilus, and provide a D-Bus service
for the "open with" GUI.  I'm 51% leaning towards this option, since
then this would have a chance of working with a desktop-specific GUI,
depending on your choice of desktop environment --- aside from promoting
the use of D-Bus for this kind of stuff.

Thoughts?

Oh my god, this is a nice little project for the Summer of Code... it
would involve figuring out the above, and also changing Firefox to use
it :)

  Federico