Auto merge of #26955 - gterzian:fix_parser_borrow, r=jdm

Do not trace pending parsers

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FIX https://github.com/servo/servo/issues/26857

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- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix #___ (GitHub issue number if applicable)

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because ___

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components/script/dom/bindings/trace.rs

@@ -43,6 +43,7 @@ use crate::dom::htmlimageelement::SourceSet;
 use crate::dom::htmlmediaelement::{HTMLMediaElementFetchContext, MediaFrameRenderer};
 use crate::dom::identityhub::Identities;
 use crate::script_runtime::StreamConsumer;
+use crate::script_thread::IncompleteParserContexts;
 use crate::task::TaskBox;
 use app_units::Au;
 use canvas_traits::canvas::{
@@ -184,6 +185,8 @@ pub unsafe trait JSTraceable {
 
 unsafe_no_jsmanaged_fields!(Box<dyn TaskBox>, Box<dyn EventLoopWaker>);
 
+unsafe_no_jsmanaged_fields!(IncompleteParserContexts);
+
 unsafe_no_jsmanaged_fields!(MessagePortImpl);
 unsafe_no_jsmanaged_fields!(MessagePortId);
 unsafe_no_jsmanaged_fields!(MessagePortRouterId);

components/script/dom/servoparser/mod.rs

@@ -689,7 +689,6 @@ impl Tokenizer {
 
 /// The context required for asynchronously fetching a document
 /// and parsing it progressively.
-#[derive(JSTraceable)]
 pub struct ParserContext {
     /// The parser that initiated the request.
     parser: Option<Trusted<ServoParser>>,