replace GCR granite.popover with gtk.popover [$90]

[Danielle Foré]

As of gtk 3.12, there is a popover widget in Gtk. The granite one should be replaced with this new Gtk widget.

[Cody Garver (codygarver)]

Bounty: https://www.bountysource.com/issues/1427530-replace-granite-popover-with-gtk-popover

[Przemysław Sitek (el.pescado)]

I see two major obstacles in implementing thig, both stemming from the fact that Gtk.Popover is not a drop-in replacement for Granite PopOver. Gtranite Popover is a Gtk.Dialog, whereas Gtk counterpart is just a Gtk.Container. This has two consequences:

1. One cannot use it in conjunction with Gtk.Dialog.run so adding bookmark has to be changed from "synchronous" model to "continuation-passing asynchronous" model.

2. As Gtk.Popover is not a window, it has to fit its toplevel window, which may pose problem in case contents of popover are big (example: security info "window").

[Cris Dywan (kalikiana)]

Point 1. is not a big issue as I see it. The security details are already modeless. The bookmark dialog uses gtk_dialog_run but can easily be adapted to connect the response callback - the pop over is dismissed by loss of focus so it will work effectively the same way.

On point 2. I suspect if they get so big that the actual browser is smaller, it's also a problem in the case where it's a window. In that case we would allow them to scroll.

[Yosef Or Boczko (yoseforb)]

One question for the bookmark-dialog/popover.
When I try to add bookmark from the item from the gear-menu, it jump me to the other side of the window
and show popover thas point to the bookmark button in the toolbar.
When I try to add bookmark by the bookmark button in the toolbar it reasonable, but not in the case above.
In the other cases (no bookmark button in the toolbar or from context-menu from the sidebar) it show dialog and
not popover thas point to the bookmark button in the toolbar..

I think it better to show always dialog, not popover, for consistency.
If I menthion the point of edit bookmark, it always come as popover.
In the bottom line, for the same action/content, sometimes the user see dialog, sometimes popover.
It better to show dialog always (or popover always, but the popover had to point to some widget...).