gpui: Add `display_handle` implementation for Windows, update it for macOS (#52867)

Bowen Xu created 

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A

Change summary

crates/gpui_macos/src/window.rs   | 7 +------
crates/gpui_windows/src/window.rs | 3 +--
2 files changed, 2 insertions(+), 8 deletions(-)

Detailed changes

crates/gpui_macos/src/window.rs 🔗 

@@ -1701,12 +1701,7 @@ impl rwh::HasWindowHandle for MacWindow {
 
 impl rwh::HasDisplayHandle for MacWindow {
     fn display_handle(&self) -> Result<rwh::DisplayHandle<'_>, rwh::HandleError> {
-        // SAFETY: This is a no-op on macOS
-        unsafe {
-            Ok(rwh::DisplayHandle::borrow_raw(
-                rwh::AppKitDisplayHandle::new().into(),
-            ))
-        }
+        Ok(rwh::DisplayHandle::appkit())
     }
 }

crates/gpui_windows/src/window.rs 🔗 

@@ -540,10 +540,9 @@ impl rwh::HasWindowHandle for WindowsWindow {
     }
 }
 
-// todo(windows)
 impl rwh::HasDisplayHandle for WindowsWindow {
     fn display_handle(&self) -> std::result::Result<rwh::DisplayHandle<'_>, rwh::HandleError> {
-        unimplemented!()
+        Ok(rwh::DisplayHandle::windows())
     }
 }