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.

---
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- [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.

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1 files changed, 2 insertions, 3 deletions

diff --git a/components/layout/context.rs b/components/layout/context.rs
index a17bc1db4ee..d8d0c8b47a1 100644
--- a/components/layout/context.rs
+++ b/components/layout/context.rs
@@ -5,7 +5,6 @@
 //! Data needed by the layout thread.
 
 use crate::display_list::items::{OpaqueNode, WebRenderImageInfo};
-use crate::opaque_node::OpaqueNodeMethods;
 use fnv::FnvHasher;
 use gfx::font_cache_thread::FontCacheThread;
 use gfx::font_context::FontContext;
@@ -121,7 +120,7 @@ impl<'a> LayoutContext<'a> {
             ImageCacheResult::Pending(id) => {
                 let image = PendingImage {
                     state: PendingImageState::PendingResponse,
-                    node: node.to_untrusted_node_address(),
+                    node: node.into(),
                     id,
                     origin: self.origin.clone(),
                 };
@@ -132,7 +131,7 @@ impl<'a> LayoutContext<'a> {
             ImageCacheResult::ReadyForRequest(id) => {
                 let image = PendingImage {
                     state: PendingImageState::Unrequested(url),
-                    node: node.to_untrusted_node_address(),
+                    node: node.into(),
                     id,
                     origin: self.origin.clone(),
                 };