style: Make Invalidation work in terms of a dependency, not a selector.

That way we can look at the parent dependency as described in the previous
patch. An alternative would be to add a:

    parent_dependency: Option<&'a Dependency>

on construction to `Invalidation`, but this way seems slightly better to avoid
growing the struct. It's not even one more indirection because the selector is
contained directly in the Dependency struct.

Differential Revision: https://phabricator.services.mozilla.com/D71422

components/style/dom_apis.rs

@@ -9,6 +9,7 @@ use crate::context::QuirksMode;
 use crate::dom::{TDocument, TElement, TNode, TShadowRoot};
 use crate::invalidation::element::invalidator::{DescendantInvalidationLists, Invalidation};
 use crate::invalidation::element::invalidator::{InvalidationProcessor, InvalidationVector};
+use crate::invalidation::element::invalidation_map::Dependency;
 use crate::Atom;
 use selectors::attr::CaseSensitivity;
 use selectors::matching::{self, MatchingContext, MatchingMode};
@@ -130,7 +131,7 @@ where
 {
     results: &'a mut Q::Output,
     matching_context: MatchingContext<'a, E::Impl>,
-    selector_list: &'a SelectorList<E::Impl>,
+    dependencies: &'a [Dependency],
 }
 
 impl<'a, E, Q> InvalidationProcessor<'a, E> for QuerySelectorProcessor<'a, E, Q>
@@ -143,6 +144,11 @@ where
         true
     }
 
+    fn check_outer_dependency(&mut self, _: &Dependency, _: E) -> bool {
+        debug_assert!(false, "How? We should only have parent-less dependencies here!");
+        true
+    }
+
     fn collect_invalidations(
         &mut self,
         element: E,
@@ -171,11 +177,10 @@ where
             self_invalidations
         };
 
-        for selector in self.selector_list.0.iter() {
+        for dependency in self.dependencies.iter() {
             target_vector.push(Invalidation::new(
-                selector,
+                dependency,
                 self.matching_context.current_host.clone(),
-                0,
             ))
         }
 
@@ -642,10 +647,13 @@ pub fn query_selector<E, Q>(
     if root_element.is_some() || !invalidation_may_be_useful {
         query_selector_slow::<E, Q>(root, selector_list, results, &mut matching_context);
     } else {
+        let dependencies = selector_list.0.iter().map(|selector| {
+            Dependency::for_full_selector_invalidation(selector.clone())
+        }).collect::<SmallVec<[_; 5]>>();
         let mut processor = QuerySelectorProcessor::<E, Q> {
             results,
             matching_context,
-            selector_list,
+            dependencies: &dependencies,
         };
 
         for node in root.dom_children() {