Auto merge of #20743 - paulrouget:rmFwdEvent, r=emilio

Remove useless message

<!-- Please describe your changes on the following line: -->

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/20743)
<!-- Reviewable:end -->

components/script_traits/script_msg.rs

@@ -3,7 +3,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use AnimationState;
-use CompositorEvent;
 use DocumentState;
 use IFrameLoadInfo;
 use IFrameLoadInfoWithData;
@@ -82,8 +81,6 @@ pub enum ScriptMsg {
     CreateCanvasPaintThread(Size2D<i32>, IpcSender<(IpcSender<CanvasMsg>, CanvasId)>),
     /// Notifies the constellation that this frame has received focus.
     Focus,
-    /// Forward an event that was sent to the parent window.
-    ForwardEvent(PipelineId, CompositorEvent),
     /// Requests that the constellation retrieve the current contents of the clipboard
     GetClipboardContents(IpcSender<String>),
     /// Get the browsing context id for a given pipeline.