owncloud: Adjust the UI so that we can use a header bar in the dialog

Using a header bar means that the dialog can emit both
GTK_RESPONSE_CANCEL (from the cancel button) and
GTK_RESPONSE_DELETE_EVENT (from the Esc key), so we should account for
that. This is also a good opportunity to stop using the action area.

Fixes: https://bugzilla.gnome.org/729638
exchange: Adjust the UI so that we can use a header bar in the dialog

Using a header bar means that the dialog can emit both
GTK_RESPONSE_CANCEL (from the cancel button) and
GTK_RESPONSE_DELETE_EVENT (from the Esc key), so we should account for
that. This is also a good opportunity to stop using the action area.

Fixes: https://bugzilla.gnome.org/729638
imap-smtp: Adjust the UI so that we can use a header bar in the dialog

Using a header bar means that the dialog can emit both
GTK_RESPONSE_CANCEL (from the cancel button) and
GTK_RESPONSE_DELETE_EVENT (from the Esc key), so we should account for
that. This is also a good opportunity to stop using the action area.

Fixes: https://bugzilla.gnome.org/729638
kerberos: Adjust the UI so that we can use a header bar in the dialog

This is also a good opportunity to stop using the action area.

Fixes: https://bugzilla.gnome.org/729638
oauth: Remove support for using an external browser

We really do want to use the embedded web view, and we have never used
the external browser option in any provider that is worth using. Now
that we are giving the dialogs a facelift by using header bars, it is a
good opportunity to also get rid of this unused code because there is
no way to test it.

Fixes: https://bugzilla.gnome.org/729638
oauth: Adjust the UI so that we can use a header bar in the dialog

There is no need to check the cookies because there are no action
buttons anymore. Now we always have a 'X' in the header bar, which does
not look odd even if the web UI has its own elements for cancellation.
This has the nice side-effect of having a way to bail out from the
whole operation if the embedded web view misbehaves.

We might want to get rid of the get_authentication_cookie virtual
method in future.

Fixes: https://bugzilla.gnome.org/729638
oauth2: Remove support for using an external browser

We really do want to use the embedded web view, and we have never used
the external browser option in any provider that is worth using. Now
that we are giving the dialogs a facelift by using header bars, it is a
good opportunity to also get rid of this unused code because there is
no way to test it.

Fixes: https://bugzilla.gnome.org/729638
oauth2: Adjust the UI so that we can use a header bar in the dialog

There is no need to check the cookies because there are no action
buttons anymore. Now we always have a 'X' in the header bar, which does
not look odd even if the web UI has its own elements for cancellation.
This has the nice side-effect of having a way to bail out from the
whole operation if the embedded web view misbehaves.

We might want to get rid of the get_authentication_cookie virtual
method in future.

Fixes: https://bugzilla.gnome.org/729638