The motivation is that this will need to be called from a
non-Win32 thread and so shouldn't use the Win32 API.  An
added benefit is that it will eliminate the 16ms jitter
associated with GetTickCount().

The instance of the helper on the user-side is temporary.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Andrew Eikum <aeikum@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>