add cancelable property to the TouchEvent (#35713)

* add `cancelable` property to the `TouchEvent`
set cancellable = false when sending move events to script, if the first touch_move event did not cancel it

Signed-off-by: kongbai1996 <1782765876@qq.com>

* modified review commentss

Signed-off-by: kongbai1996 <1782765876@qq.com>

---------

Signed-off-by: kongbai1996 <1782765876@qq.com>

components/compositing/compositor.rs

@@ -1396,7 +1396,7 @@ impl IOCompositor {
         self.send_touch_event(event);
     }
 
-    fn on_touch_move(&mut self, event: TouchEvent) {
+    fn on_touch_move(&mut self, mut event: TouchEvent) {
         let action: TouchMoveAction = self.touch_handler.on_touch_move(event.id, event.point);
         if TouchMoveAction::NoAction != action {
             // if first move processed and allowed, we directly process the move event,
@@ -1405,6 +1405,8 @@ impl IOCompositor {
                 .touch_handler
                 .move_allowed(self.touch_handler.current_sequence_id)
             {
+                // https://w3c.github.io/touch-events/#cancelability
+                event.disable_cancelable();
                 match action {
                     TouchMoveAction::Scroll(delta, point) => self.on_scroll_window_event(
                         ScrollLocation::Delta(LayoutVector2D::from_untyped(delta.to_untyped())),

components/script/dom/document.rs

@@ -2090,7 +2090,7 @@ impl Document {
             window,
             DOMString::from(event_name),
             EventBubbles::Bubbles,
-            EventCancelable::Cancelable,
+            EventCancelable::from(event.is_cancelable()),
             Some(window),
             0i32,
             &touches,

components/shared/embedder/input_events.rs

@@ -147,6 +147,8 @@ pub struct TouchEvent {
     pub event_type: TouchEventType,
     pub id: TouchId,
     pub point: DevicePoint,
+    /// cancelable default value is true, once the first move has been processed by script disable it.
+    cancelable: bool,
     /// The sequence_id will be set by servo's touch handler.
     sequence_id: Option<TouchSequenceId>,
 }
@@ -158,6 +160,7 @@ impl TouchEvent {
             id,
             point,
             sequence_id: None,
+            cancelable: true,
         }
     }
     /// Embedders should ignore this.
@@ -175,6 +178,16 @@ impl TouchEvent {
     pub fn expect_sequence_id(&self) -> TouchSequenceId {
         self.sequence_id.expect("Sequence ID not initialized")
     }
+
+    #[doc(hidden)]
+    pub fn disable_cancelable(&mut self) {
+        self.cancelable = false;
+    }
+
+    #[doc(hidden)]
+    pub fn is_cancelable(&self) -> bool {
+        self.cancelable
+    }
 }
 
 /// Mode to measure WheelDelta floats in