desktop: Remove RuffleEvent::ThemeChanged

This event is no longer needed as theme is now changed synchronously.

desktop/src/app.rs

@@ -539,10 +539,6 @@ impl App {
                     return;
                 }
 
-                winit::event::Event::UserEvent(RuffleEvent::ThemeChanged(theme)) => {
-                    self.gui.borrow().set_theme(theme);
-                }
-
                 _ => (),
             }
 

desktop/src/custom_event.rs

@@ -1,7 +1,6 @@
 //! Custom event type for desktop ruffle
 
 use crate::player::LaunchOptions;
-use winit::window::Theme;
 
 /// User-defined events.
 pub enum RuffleEvent {
@@ -25,7 +24,4 @@ pub enum RuffleEvent {
 
     /// The user selected an item in the right-click context menu.
     ContextMenuItemClicked(usize),
-
-    /// System theme has changed.
-    ThemeChanged(Theme),
 }