The Qt Quick Designer synthesized a few theme colors from existing theme
colors. That was in order to prevent the need for 6 theme colors being
defined in every theme. It turned out, however, that being able to
define these if favorable.
Todo in follow-up commit: remove QmlDesigner::Theme::qmlDesigner...()
functions, and fix up the qml, accordingly.
Change-Id: Ica85df5472cd7b9da8bf215eb6dbdcf608a4fb2d
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>