3 files changed, 39 insertions, 2 deletions
diff --git a/components/compositing/compositor.rs b/components/compositing/compositor.rs
index 41286a2760a..b1669277ba1 100644
--- a/components/compositing/compositor.rs
+++ b/components/compositing/compositor.rs
@@ -26,9 +26,9 @@ use crossbeam_channel::{Receiver, Sender};
 use dpi::PhysicalSize;
 use embedder_traits::{
     CompositorHitTestResult, Cursor, InputEvent, MouseButtonEvent, MouseMoveEvent, ShutdownState,
-    TouchEventType, UntrustedNodeAddress, ViewportDetails,
+    TouchEventType, UntrustedNodeAddress, ViewportDetails, WheelDelta, WheelEvent, WheelMode,
 };
-use euclid::{Point2D, Rect, Scale, Size2D, Transform3D};
+use euclid::{Point2D, Rect, Scale, Size2D, Transform3D, Vector2D};
 use fnv::FnvHashMap;
 use ipc_channel::ipc::{self, IpcSharedMemory};
 use libc::c_void;
@@ -646,6 +646,26 @@ impl IOCompositor {
                     .dispatch_input_event(InputEvent::MouseMove(MouseMoveEvent { point }));
             },
 
+            CompositorMsg::WebDriverWheelScrollEvent(webview_id, x, y, delta_x, delta_y) => {
+                let Some(webview_renderer) = self.webview_renderers.get_mut(webview_id) else {
+                    warn!("Handling input event for unknown webview: {webview_id}");
+                    return;
+                };
+                let delta = WheelDelta {
+                    x: delta_x,
+                    y: delta_y,
+                    z: 0.0,
+                    mode: WheelMode::DeltaPixel,
+                };
+                let dppx = webview_renderer.device_pixels_per_page_pixel();
+                let point = dppx.transform_point(Point2D::new(x, y));
+                let scroll_delta =
+                    dppx.transform_vector(Vector2D::new(delta_x as f32, delta_y as f32));
+                webview_renderer
+                    .dispatch_input_event(InputEvent::Wheel(WheelEvent { delta, point }));
+                webview_renderer.on_webdriver_wheel_action(scroll_delta, point);
+            },
+
             CompositorMsg::SendInitialTransaction(pipeline) => {
                 let mut txn = Transaction::new();
                 txn.set_display_list(WebRenderEpoch(0), (pipeline, Default::default()));
diff --git a/components/compositing/tracing.rs b/components/compositing/tracing.rs
index ae7338106d0..a8bb8b42bb8 100644
--- a/components/compositing/tracing.rs
+++ b/components/compositing/tracing.rs
@@ -42,6 +42,7 @@ mod from_constellation {
                 Self::LoadComplete(..) => target!("LoadComplete"),
                 Self::WebDriverMouseButtonEvent(..) => target!("WebDriverMouseButtonEvent"),
                 Self::WebDriverMouseMoveEvent(..) => target!("WebDriverMouseMoveEvent"),
+                Self::WebDriverWheelScrollEvent(..) => target!("WebDriverWheelScrollEvent"),
                 Self::SendInitialTransaction(..) => target!("SendInitialTransaction"),
                 Self::SendScrollNode(..) => target!("SendScrollNode"),
                 Self::SendDisplayList { .. } => target!("SendDisplayList"),
diff --git a/components/compositing/webview_renderer.rs b/components/compositing/webview_renderer.rs
index 614ef0ff4c3..f76dc68013d 100644
--- a/components/compositing/webview_renderer.rs
+++ b/components/compositing/webview_renderer.rs
@@ -726,6 +726,22 @@ impl WebViewRenderer {
             }));
     }
 
+    /// Push scroll pending event when receiving wheel action from webdriver
+    pub(crate) fn on_webdriver_wheel_action(
+        &mut self,
+        scroll_delta: Vector2D<f32, DevicePixel>,
+        point: Point2D<f32, DevicePixel>,
+    ) {
+        if self.global.borrow().shutdown_state() != ShutdownState::NotShuttingDown {
+            return;
+        }
+
+        let scroll_location =
+            ScrollLocation::Delta(LayoutVector2D::from_untyped(scroll_delta.to_untyped()));
+        let cursor = DeviceIntPoint::new(point.x as i32, point.y as i32);
+        self.on_scroll_window_event(scroll_location, cursor)
+    }
+
     pub(crate) fn process_pending_scroll_events(&mut self, compositor: &mut IOCompositor) {
         if self.pending_scroll_zoom_events.is_empty() {
             return;