Adding gnome-keyring support to evince for encrypted PDFs

[Caleb Groom <caleb calebgroom com>]

I've started a hack for Evince that will add gnome-keyring support for
opening encrypted PDFs.  Before I get too deep into it I figured I
better discuss it with the maintainers and make sure the feature would
be welcomed.

If you aren't familiar with gnome-keyring you might want to peak at the
keyring intro[1].  Basically, it allows GNOME applications to save and
recall passwords that have been supplied by the user.  You can find
gnome-keyring support in nautilus' connect to server authentication
dialog[2].

My proposed hack would allow Evince users to save the password to an
encrypted file for the current session, or to the default keyring (long
term storage).

I've copied the UI that nautilus uses for consistencies sake.  The
visual impact of the patch can be found in the before[3] and after[4]
screenies.

At this point I've only done the UI, I haven't hooked up the
gnome-keyring side.

Thoughts?  Comments?

[1]
http://cvs.gnome.org/viewcvs/gnome-keyring/keyring-intro.txt?view=markup
[2] http://calebgroom.com/tmp/evince/nautilus_password.png
[3] http://calebgroom.com/tmp/evince/evince_password_before.png
[4] http://calebgroom.com/tmp/evince/evince_password_after.png