Auto merge of #13110 - emilio:element-flags, r=SimonSapin

Fix incremental restyling under some circumstances due to our bogus use of ElementFlags.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors

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- [x] There are tests for these changes OR

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Depends on https://github.com/servo/rust-selectors/pull/98

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This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/13110)
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1 files changed, 5 insertions, 3 deletions

diff --git a/components/style/restyle_hints.rs b/components/style/restyle_hints.rs
index c150f1802dc..2801b17e368 100644
--- a/components/style/restyle_hints.rs
+++ b/components/style/restyle_hints.rs
@@ -8,8 +8,8 @@ use element_state::*;
 #[cfg(feature = "servo")]
 use heapsize::HeapSizeOf;
 use selector_impl::{ElementExt, TheSelectorImpl, NonTSPseudoClass, AttrValue};
-use selectors::matching::StyleRelations;
 use selectors::matching::matches_complex_selector;
+use selectors::matching::{MatchingReason, StyleRelations};
 use selectors::parser::{AttrSelector, Combinator, ComplexSelector, SimpleSelector, SelectorImpl};
 use selectors::{Element, MatchAttr};
 use std::clone::Clone;
@@ -476,10 +476,12 @@ impl DependencySet {
             if (attrs_changed || state_changes.intersects(dep.sensitivities.states)) && !hint.intersects(dep.hint) {
                 let matched_then =
                     matches_complex_selector(&dep.selector, snapshot, None,
-                                             &mut StyleRelations::empty());
+                                             &mut StyleRelations::empty(),
+                                             MatchingReason::Other);
                 let matches_now =
                     matches_complex_selector(&dep.selector, element, None,
-                                             &mut StyleRelations::empty());
+                                             &mut StyleRelations::empty(),
+                                             MatchingReason::Other);
                 if matched_then != matches_now {
                     hint.insert(dep.hint);
                 }