Implement web_sys::Canvas event listeners

src/platform_impl/web/window.rs

@@ -24,9 +24,9 @@ impl Window {
         attr: WindowAttributes,
         _: PlatformSpecificBuilderAttributes,
     ) -> Result<Self, RootOE> {
-        let canvas = backend::Canvas::create()?;
+        let mut canvas = backend::Canvas::create()?;
 
-        target.register(&canvas);
+        target.register(&mut canvas);
 
         let runner = target.runner.clone();
         let redraw = Box::new(move || {
@@ -58,6 +58,10 @@ impl Window {
         Ok(window)
     }
 
+    pub fn canvas(&self) -> &backend::Canvas {
+        &self.canvas
+    }
+
     pub fn set_title(&self, title: &str) {
         backend::Document::set_title(title);
     }
@@ -256,13 +260,6 @@ impl Window {
     }
 }
 
-#[cfg(feature = "stdweb")]
-impl WindowExtStdweb for RootWindow {
-    fn canvas(&self) -> CanvasElement {
-        self.window.canvas.clone()
-    }
-}
-
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Id;