Epiphany freeze break request: incognito mode tab style

[Michael Catanzaro <mcatanzaro igalia com>]

Hi,

I'd like to request a UI freeze break for Epiphany's tab bar. In 
incognito mode, they tabs are currently gray, but this doesn't look 
good with the new version of Adwaita. We've changed the tab bar to be 
blue in master. This request is to backport the change to 3.32.

Before: 
https://gitlab.gnome.org/GNOME/epiphany/merge_requests/184#note_433819

After: https://gitlab.gnome.org/GNOME/epiphany/merge_requests/184 
(first comment)

Thanks,

Michael