Implement ApplicationHandler::can_create|destroy_surfaces() (#3765)

src/platform_impl/apple/uikit/app_state.rs

@@ -496,8 +496,12 @@ pub fn did_finish_launching(mtm: MainThreadMarker) {
 
     let (windows, events) = AppState::get_mut(mtm).did_finish_launching_transition();
 
-    let events = std::iter::once(EventWrapper::StaticEvent(Event::NewEvents(StartCause::Init)))
-        .chain(events);
+    let events = [
+        EventWrapper::StaticEvent(Event::NewEvents(StartCause::Init)),
+        EventWrapper::StaticEvent(Event::CreateSurfaces),
+    ]
+    .into_iter()
+    .chain(events);
     handle_nonuser_events(mtm, events);
 
     // the above window dance hack, could possibly trigger new windows to be created.

src/platform_impl/apple/uikit/event_loop.rs

@@ -130,6 +130,7 @@ fn map_user_event<A: ApplicationHandler>(
         },
         Event::Suspended => app.suspended(window_target),
         Event::Resumed => app.resumed(window_target),
+        Event::CreateSurfaces => app.can_create_surfaces(window_target),
         Event::AboutToWait => app.about_to_wait(window_target),
         Event::LoopExiting => app.exiting(window_target),
         Event::MemoryWarning => app.memory_warning(window_target),