Progress Bar: Fix Class Style & Repainting (resend2)

[Alexandre Julliard]

Robert Shearman <rob at codeweavers.com> writes:

> Changelog:
> - Fix class style to include the hbrBackground member.
> - Fix repainting issues introduced by this change.
> - Add WM_ERASEBKGND handler and remove background drawing code from
> the WM_PAINT handler.

Isn't that going to cause a lot of flicker?  This was the reason for
the existing code, because otherwise it looks really bad with apps
that update the progress bar a lot.

-- 
Alexandre Julliard
julliard at winehq.org