Add cancel event (#4476)

* feat: add cancel event

* feat: provide cancel event

* feat: insert cancel event in web

* fix: typo

* feat: propagate implementation of cancel event

* fix merge conflicts / tests

---------

Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>

packages/html/src/transit.rs

@@ -65,6 +65,9 @@ fn deserialize_raw(name: &str, data: &serde_json::Value) -> Result<EventData, se
     }
 
     let data = match name {
+        // Cancel
+        "cancel" => Cancel(de(data)?),
+
         // Mouse
         "click" | "contextmenu" | "dblclick" | "doubleclick" | "mousedown" | "mouseenter"
         | "mouseleave" | "mousemove" | "mouseout" | "mouseover" | "mouseup" => Mouse(de(data)?),
@@ -154,6 +157,7 @@ impl HtmlEvent {
 #[serde(untagged)]
 #[non_exhaustive]
 pub enum EventData {
+    Cancel(SerializedCancelData),
     Mouse(SerializedMouseData),
     Clipboard(SerializedClipboardData),
     Composition(SerializedCompositionData),
@@ -179,6 +183,9 @@ pub enum EventData {
 impl EventData {
     pub fn into_any(self) -> Rc<dyn Any> {
         match self {
+            EventData::Cancel(data) => {
+                Rc::new(PlatformEventData::new(Box::new(data))) as Rc<dyn Any>
+            }
             EventData::Mouse(data) => {
                 Rc::new(PlatformEventData::new(Box::new(data))) as Rc<dyn Any>
             }
@@ -291,6 +298,14 @@ impl HtmlEventConverter for SerializedHtmlEventConverter {
             .into()
     }
 
+    fn convert_cancel_data(&self, event: &PlatformEventData) -> CancelData {
+        event
+            .downcast::<SerializedCancelData>()
+            .cloned()
+            .unwrap()
+            .into()
+    }
+
     fn convert_clipboard_data(&self, event: &PlatformEventData) -> ClipboardData {
         event
             .downcast::<SerializedClipboardData>()