[GTK3] Have checkboxes and radiobuttons respect the user's color scheme.

Authored by cblack on Aug 28 2019, 9:21 PM.

Description

[GTK3] Have checkboxes and radiobuttons respect the user's color scheme.

Summary: Checkboxes and radiobuttons are now recolored according to the user's colour tastes.

Test Plan:
Old:

New:

Reviewers: Breeze, ndavis

Reviewed By: Breeze, ndavis

Subscribers: ndavis, ngraham, plasma-devel

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D23547