style: Fix container units on ::backdrop

Differential Revision: https://phabricator.services.mozilla.com/D165542

components/style/properties/cascade.rs

@@ -55,6 +55,7 @@ pub fn cascade<E>(
     pseudo: Option<&PseudoElement>,
     rule_node: &StrongRuleNode,
     guards: &StylesheetGuards,
+    originating_element_style: Option<&ComputedValues>,
     parent_style: Option<&ComputedValues>,
     parent_style_ignoring_first_line: Option<&ComputedValues>,
     layout_parent_style: Option<&ComputedValues>,
@@ -73,6 +74,7 @@ where
         pseudo,
         rule_node,
         guards,
+        originating_element_style,
         parent_style,
         parent_style_ignoring_first_line,
         layout_parent_style,
@@ -173,6 +175,7 @@ fn cascade_rules<E>(
     pseudo: Option<&PseudoElement>,
     rule_node: &StrongRuleNode,
     guards: &StylesheetGuards,
+    originating_element_style: Option<&ComputedValues>,
     parent_style: Option<&ComputedValues>,
     parent_style_ignoring_first_line: Option<&ComputedValues>,
     layout_parent_style: Option<&ComputedValues>,
@@ -196,6 +199,7 @@ where
         rule_node,
         guards,
         DeclarationIterator::new(rule_node, guards, pseudo),
+        originating_element_style,
         parent_style,
         parent_style_ignoring_first_line,
         layout_parent_style,
@@ -232,6 +236,7 @@ pub fn apply_declarations<'a, E, I>(
     rules: &StrongRuleNode,
     guards: &StylesheetGuards,
     iter: I,
+    originating_element_style: Option<&ComputedValues>,
     parent_style: Option<&ComputedValues>,
     parent_style_ignoring_first_line: Option<&ComputedValues>,
     layout_parent_style: Option<&ComputedValues>,
@@ -246,6 +251,10 @@ where
     E: TElement,
     I: Iterator<Item = (&'a PropertyDeclaration, CascadePriority)>,
 {
+    debug_assert_eq!(
+        originating_element_style.is_some(),
+        element.is_some() && pseudo.is_some()
+    );
     debug_assert!(layout_parent_style.is_none() || parent_style.is_some());
     debug_assert_eq!(
         parent_style.is_some(),
@@ -282,7 +291,7 @@ where
 
     let is_root_element = pseudo.is_none() && element.map_or(false, |e| e.is_root());
     let container_size_query =
-        ContainerSizeQuery::for_option_element(element, pseudo.and(parent_style));
+        ContainerSizeQuery::for_option_element(element, originating_element_style);
 
     let mut context = computed::Context::new(
         // We'd really like to own the rules here to avoid refcount traffic, but
@@ -339,6 +348,7 @@ where
             if let Some(visited_rules) = visited_rules {
                 cascade.compute_visited_style_if_needed(
                     element,
+                    originating_element_style,
                     parent_style,
                     parent_style_ignoring_first_line,
                     layout_parent_style,
@@ -725,6 +735,7 @@ impl<'a, 'b: 'a> Cascade<'a, 'b> {
     fn compute_visited_style_if_needed<E>(
         &mut self,
         element: Option<E>,
+        originating_element_style: Option<&ComputedValues>,
         parent_style: Option<&ComputedValues>,
         parent_style_ignoring_first_line: Option<&ComputedValues>,
         layout_parent_style: Option<&ComputedValues>,
@@ -755,6 +766,7 @@ impl<'a, 'b: 'a> Cascade<'a, 'b> {
             self.context.builder.pseudo,
             visited_rules,
             guards,
+            visited_parent!(originating_element_style),
             visited_parent!(parent_style),
             visited_parent!(parent_style_ignoring_first_line),
             visited_parent!(layout_parent_style),

components/style/style_resolver.rs

@@ -349,6 +349,7 @@ where
             pseudo,
             inputs,
             &self.context.shared.guards,
+            pseudo.and(parent_style),
             parent_style,
             parent_style,
             layout_parent_style,

components/style/stylist.rs

@@ -895,8 +895,9 @@ impl Stylist {
             },
             pseudo,
             guards,
+            /* originating_element_style */ None,
             parent,
-            None,
+            /* element */ None,
         )
     }
 
@@ -989,6 +990,7 @@ impl Stylist {
             cascade_inputs,
             pseudo,
             guards,
+            Some(originating_element_style),
             Some(parent_style),
             Some(element),
         ))
@@ -1003,6 +1005,7 @@ impl Stylist {
         inputs: CascadeInputs,
         pseudo: &PseudoElement,
         guards: &StylesheetGuards,
+        originating_element_style: Option<&ComputedValues>,
         parent_style: Option<&ComputedValues>,
         element: Option<E>,
     ) -> Arc<ComputedValues>
@@ -1026,6 +1029,7 @@ impl Stylist {
             Some(pseudo),
             inputs,
             guards,
+            originating_element_style,
             parent_style,
             parent_style,
             parent_style,
@@ -1052,6 +1056,7 @@ impl Stylist {
         pseudo: Option<&PseudoElement>,
         inputs: CascadeInputs,
         guards: &StylesheetGuards,
+        originating_element_style: Option<&ComputedValues>,
         parent_style: Option<&ComputedValues>,
         parent_style_ignoring_first_line: Option<&ComputedValues>,
         layout_parent_style: Option<&ComputedValues>,
@@ -1087,6 +1092,7 @@ impl Stylist {
             pseudo,
             inputs.rules.as_ref().unwrap_or(self.rule_tree.root()),
             guards,
+            originating_element_style,
             parent_style,
             parent_style_ignoring_first_line,
             layout_parent_style,
@@ -1505,6 +1511,7 @@ impl Stylist {
                     ),
                 )
             }),
+            /* originating_element_style */ None,
             Some(parent_style),
             Some(parent_style),
             Some(parent_style),