Auto merge of #18862 - emilio:stylo-element-closest, r=heycam

stylo: Use stylo for Element::Closest.

Bug: 1407952
Reviewed-by: heycam
MozReview-Commit-ID: 3H2piFT2CfF

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ports/geckolib/glue.rs

@@ -6,7 +6,7 @@ use cssparser::{Parser, ParserInput};
 use cssparser::ToCss as ParserToCss;
 use env_logger::LogBuilder;
 use malloc_size_of::MallocSizeOfOps;
-use selectors::{self, Element};
+use selectors::{self, Element, NthIndexCache};
 use selectors::matching::{MatchingContext, MatchingMode, matches_selector};
 use servo_arc::{Arc, ArcBorrow, RawOffsetArc};
 use std::cell::RefCell;
@@ -1520,6 +1520,36 @@ pub extern "C" fn Servo_StyleRule_SelectorMatchesElement(rule: RawServoStyleRule
     })
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn Servo_SelectorList_Closest<'a>(
+    element: RawGeckoElementBorrowed<'a>,
+    selectors: RawServoSelectorListBorrowed,
+) -> RawGeckoElementBorrowedOrNull<'a> {
+    use std::borrow::Borrow;
+
+    let mut nth_index_cache = NthIndexCache::default();
+
+    let element = GeckoElement(element);
+    let mut context = MatchingContext::new(
+        MatchingMode::Normal,
+        None,
+        Some(&mut nth_index_cache),
+        element.owner_document_quirks_mode(),
+    );
+    context.scope_element = Some(element.opaque());
+
+    let selectors = ::selectors::SelectorList::from_ffi(selectors).borrow();
+    let mut current = Some(element);
+    while let Some(element) = current.take() {
+        if selectors::matching::matches_selector_list(&selectors, &element, &mut context) {
+            return Some(element.0);
+        }
+        current = element.parent_element();
+    }
+
+    return None;
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn Servo_SelectorList_Matches(
     element: RawGeckoElementBorrowed,