Update macos backend for rwh 0.6 and remove dead code.

src/backend/macos/file_dialog.rs

@@ -6,8 +6,6 @@ use crate::{FileDialog, FileHandle};
 
 use std::path::PathBuf;
 
-pub use objc::runtime::{BOOL, NO};
-
 use super::modal_future::ModalFuture;
 use super::utils::{run_on_main, INSWindow, NSWindow};
 

src/backend/macos/utils/window.rs

@@ -10,8 +10,12 @@ pub trait INSWindow: INSObject {
     fn from_raw_window_handle(h: &RawWindowHandle) -> Id<Self> {
         match h {
             RawWindowHandle::AppKit(h) => {
-                let id = h.ns_window as *mut Self;
-                unsafe { Id::from_ptr(id) }
+                let id = h.ns_view.as_ptr() as *mut Self;
+                let id: Id<Self> = unsafe { Id::from_ptr(id) };
+
+                let window: *mut NSWindow = unsafe { msg_send![id, window] };
+
+                unsafe { Id::from_ptr(window as *mut Self) }
             }
             _ => unreachable!("unsupported window handle, expected: MacOS"),
         }