[webdriver] Add synchronization for wheel action (#37260)

Implement action synchronization for wheel event. Previously only done
for pointer here https://github.com/servo/servo/pull/36932.

Testing:
`tests/wpt/meta/webdriver/tests/classic/perform_actions/wheel.py`

---------

Signed-off-by: PotatoCP <kenzieradityatirtarahardja18@gmail.com>

components/shared/embedder/input_events.rs

@@ -54,7 +54,7 @@ impl InputEvent {
             InputEvent::MouseButton(event) => event.webdriver_id,
             InputEvent::MouseMove(event) => event.webdriver_id,
             InputEvent::Touch(..) => None,
-            InputEvent::Wheel(..) => None,
+            InputEvent::Wheel(event) => event.webdriver_id,
         }
     }
 
@@ -71,7 +71,9 @@ impl InputEvent {
                 event.webdriver_id = webdriver_id;
             },
             InputEvent::Touch(..) => {},
-            InputEvent::Wheel(..) => {},
+            InputEvent::Wheel(ref mut event) => {
+                event.webdriver_id = webdriver_id;
+            },
         };
 
         self
@@ -275,6 +277,17 @@ pub struct WheelDelta {
 pub struct WheelEvent {
     pub delta: WheelDelta,
     pub point: DevicePoint,
+    webdriver_id: Option<WebDriverMessageId>,
+}
+
+impl WheelEvent {
+    pub fn new(delta: WheelDelta, point: DevicePoint) -> Self {
+        WheelEvent {
+            delta,
+            point,
+            webdriver_id: None,
+        }
+    }
 }
 
 #[derive(Clone, Debug, Deserialize, Serialize)]

components/shared/embedder/webdriver.rs

@@ -50,7 +50,8 @@ pub enum WebDriverCommandMsg {
         MouseButton,
         f32,
         f32,
-        WebDriverMessageId,
+        // Should never be None.
+        Option<WebDriverMessageId>,
         IpcSender<WebDriverCommandResponse>,
     ),
     /// Act as if the mouse was moved in the browsing context with the given ID.
@@ -58,11 +59,23 @@ pub enum WebDriverCommandMsg {
         WebViewId,
         f32,
         f32,
-        WebDriverMessageId,
+        // None if it's not the last `perform_pointer_move` since we only
+        // expect one response from constellation for each tick actions.
+        Option<WebDriverMessageId>,
         IpcSender<WebDriverCommandResponse>,
     ),
     /// Act as if the mouse wheel is scrolled in the browsing context given the given ID.
-    WheelScrollAction(WebViewId, f32, f32, f64, f64),
+    WheelScrollAction(
+        WebViewId,
+        f32,
+        f32,
+        f64,
+        f64,
+        // None if it's not the last `perform_wheel_scroll` since we only
+        // expect one response from constellation for each tick actions.
+        Option<WebDriverMessageId>,
+        IpcSender<WebDriverCommandResponse>,
+    ),
     /// Set the window size.
     SetWindowSize(WebViewId, DeviceIntSize, IpcSender<Size2D<f32, CSSPixel>>),
     /// Take a screenshot of the window.