In order to show all popups on Wayland we need to set popup parent runtime for popups which don't have
fixed parent. For instance popup menus (fired after right button mouse click) can be issued on top of another popup
and we need to follow that connection on Wayland.
We track all open (active) popups to:
- close all visible tooltip windows when we're going to open another tooltip
- close concurrent popup on the same level when a new one is about to open
- get latest active popup as a parent for a new tooltip windows
- get latest active popup as a parent for a new popup menu without fixed parent
Differential Revision: https://phabricator.services.mozilla.com/D29348
--HG--
extra : moz-landing-system : lando
89dd37e531