Remove a bunch of unwrap() (#4285)

The fewer unwraps, the fewer panics

crates/eframe/src/native/wgpu_integration.rs

@@ -5,7 +5,7 @@
 //! There is a bunch of improvements we could do,
 //! like removing a bunch of `unwraps`.
 
-use std::{cell::RefCell, rc::Rc, sync::Arc, time::Instant};
+use std::{cell::RefCell, num::NonZeroU32, rc::Rc, sync::Arc, time::Instant};
 
 use parking_lot::Mutex;
 use raw_window_handle::{HasDisplayHandle as _, HasWindowHandle as _};
@@ -437,13 +437,12 @@ impl WinitApp for WgpuWinitApp {
                     self.init_run_state(egui_ctx, event_loop, storage, window, builder)?
                 };
 
-                EventResult::RepaintNow(
-                    running.shared.borrow().viewports[&ViewportId::ROOT]
-                        .window
-                        .as_ref()
-                        .unwrap()
-                        .id(),
-                )
+                let viewport = &running.shared.borrow().viewports[&ViewportId::ROOT];
+                if let Some(window) = &viewport.window {
+                    EventResult::RepaintNow(window.id())
+                } else {
+                    EventResult::Wait
+                }
             }
 
             winit::event::Event::Suspended => {
@@ -615,7 +614,9 @@ impl WgpuWinitRunning {
                 }
             }
 
-            let egui_winit = egui_winit.as_mut().unwrap();
+            let Some(egui_winit) = egui_winit.as_mut() else {
+                return EventResult::Wait;
+            };
             let mut raw_input = egui_winit.take_egui_input(window);
 
             integration.pre_update();
@@ -775,7 +776,6 @@ impl WgpuWinitRunning {
                 // See: https://github.com/rust-windowing/winit/issues/208
                 // This solves an issue where the app would panic when minimizing on Windows.
                 if let Some(viewport_id) = viewport_id {
-                    use std::num::NonZeroU32;
                     if let (Some(width), Some(height)) = (
                         NonZeroU32::new(physical_size.width),
                         NonZeroU32::new(physical_size.height),