Auto merge of #29727 - mrobinson:more-layout-dom-cleanup, r=jdm

More cleanup of the layout DOM wrappers

This PR includes two commits which continue to clean up the layout DOM wrappers.
 - in the first the unused `DangerousThreadSafeLayoutNode` trait is removed
 - in the second DOM-related code is combined into one source file in Layout 2020 and some traits are combined and removed.

---
<!-- 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
- [x] These changes fix #29688
- [x] These changes fix #29722
- [x] These changes do not require tests because they do not change behavior.

<!-- 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. -->

1 files changed, 2 insertions, 2 deletions

diff --git a/components/layout_2020/traversal.rs b/components/layout_2020/traversal.rs
index 7ddb0e85ed4..3063319fec6 100644
--- a/components/layout_2020/traversal.rs
+++ b/components/layout_2020/traversal.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use crate::context::LayoutContext;
-use crate::wrapper::GetStyleAndLayoutData;
+use crate::dom::NodeExt;
 use script_layout_interface::wrapper_traits::LayoutNode;
 use style::context::{SharedStyleContext, StyleContext};
 use style::data::ElementData;
@@ -33,7 +33,7 @@ impl<'a> RecalcStyle<'a> {
 impl<'a, 'dom, E> DomTraversal<E> for RecalcStyle<'a>
 where
     E: TElement,
-    E::ConcreteNode: LayoutNode<'dom>,
+    E::ConcreteNode: 'dom + LayoutNode<'dom>,
 {
     fn process_preorder<F>(
         &self,