The GlobalMenuBar used to hold a raw_ptr reference to its NativeWindow;
but since it doesn't use it & only wants the gfx::AcceleratedWidget info,
let's remove the NativeWindowViews reference.
AFAICT, GlobalMenuBarX11::window_ has never been used
Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Charles Kerr <charles@charleskerr.com>