Setup event handling scaffolding

macros/src/lib.rs

@@ -143,6 +143,10 @@ fn expand_struct_trait_shim(struct_name: &Ident, observed_attrs: Literal) -> syn
    attributeChangedCallback(name, oldValue, newValue) {{
         this._impl.attribute_changed_impl(this, name, oldValue, newValue);
     }}
+
+    handleComponentEvent(evt) {{
+        this._impl.handle_component_event_impl(this, evt);
+    }}
 }}
 customElements.define(\"{element_name}\", {name});
 var element = customElements.get(\"{element_name}\");
@@ -211,6 +215,11 @@ fn expand_wasm_shim(struct_name: &Ident) -> syn::ItemImpl {
                 use #trait_path;
                 self.attribute_changed(element, name, old_value, new_value);
             }
+
+            pub fn handle_component_event_impl(&self, element: &web_sys::HtmlElement, event: &web_sys::Event) {
+                use #trait_path;
+                self.handle_event(element, event);
+            }
         }
     }
 }

wasm-web-component/src/lib.rs

@@ -67,6 +67,10 @@ pub trait WebComponentBinding: WebComponentDef {
     ) {
         // noop
     }
+
+    fn handle_event(&self, _element: &HtmlElement, _event: &Event) {
+        // noop
+    }
 }
 
 /// Marker trait used in the generated shims to assert that their are Rust implemtntations