Change the window property update event to use a window id

This will hopefully enable the custom event to be sendable across threads.

sixtyfps_runtime/rendering_backends/gl/eventloop.rs

@@ -109,7 +109,7 @@ pub enum CustomEvent {
     /// request an animation frame.
     #[cfg(target_arch = "wasm32")]
     WakeUpAndPoll,
-    UpdateWindowProperties(Weak<Window>),
+    UpdateWindowProperties(winit::window::WindowId),
     Exit,
 }
 
@@ -397,8 +397,14 @@ pub fn run() {
                     });
                 }
 
-                winit::event::Event::UserEvent(CustomEvent::UpdateWindowProperties(window)) => {
+                winit::event::Event::UserEvent(CustomEvent::UpdateWindowProperties(window_id)) => {
-                    window.upgrade().map(|window| window.update_window_properties());
+                    ALL_WINDOWS.with(|windows| {
+                        if let Some(Some(window)) =
+                            windows.borrow().get(&window_id).map(|weakref| weakref.upgrade())
+                        {
+                            window.self_weak.upgrade().unwrap().update_window_properties();
+                        }
+                    });
                 }
 
                 winit::event::Event::UserEvent(CustomEvent::Exit) => {

sixtyfps_runtime/rendering_backends/gl/graphics_window.rs

@@ -461,13 +461,23 @@ impl PlatformWindow for GraphicsWindow {
     }
 
     fn request_window_properties_update(&self) {
+        match &*self.map_state.borrow() {
+            GraphicsWindowBackendState::Unmapped => {
+                // Nothing to be done if the window isn't visible. When it becomes visible,
+                // ComponentWindow::show() calls update_window_properties()
+            }
+            GraphicsWindowBackendState::Mapped(window) => {
+                let backend = window.backend.borrow();
+                let window_id = backend.window().id();
                 crate::eventloop::with_window_target(|event_loop| {
                     event_loop.event_loop_proxy().send_event(
-                crate::eventloop::CustomEvent::UpdateWindowProperties(self.self_weak.clone()),
+                        crate::eventloop::CustomEvent::UpdateWindowProperties(window_id),
                     )
                 })
                 .ok();
             }
+        }
+    }
 
     fn apply_window_properties(&self, window_item: Pin<&sixtyfps_corelib::items::Window>) {
         match &*self.map_state.borrow() {