style: Refactor :-moz-lwtheme pseudo-classes to get invalidated correctly

Use the same document state mechanism we have for :moz-locale-dir. Also,
simplify the setup of the later to be the same as :dir(), allowing the
matching code to be less repetitive.

This should fix some flakiness in chrome mochitests, but we have no existing
tests for these pseudo-classes more generally and since they're just
chrome-only I'm not super-excited about adding more.

Differential Revision: https://phabricator.services.mozilla.com/D130735

components/style/element_state.rs

@@ -137,9 +137,17 @@ bitflags! {
     /// dom/base/Document.h.
     #[derive(MallocSizeOf)]
     pub struct DocumentState: u64 {
-        /// RTL locale: specific to the XUL localedir attribute
-        const NS_DOCUMENT_STATE_RTL_LOCALE = 1 << 0;
         /// Window activation status
-        const NS_DOCUMENT_STATE_WINDOW_INACTIVE = 1 << 1;
+        const WINDOW_INACTIVE = 1 << 0;
+        /// RTL locale: specific to the XUL localedir attribute
+        const RTL_LOCALE = 1 << 1;
+        /// LTR locale: specific to the XUL localedir attribute
+        const LTR_LOCALE = 1 << 2;
+        /// LWTheme status
+        const LWTHEME = 1 << 3;
+        /// LWTheme status
+        const LWTHEME_BRIGHTTEXT = 1 << 4;
+        /// LWTheme status
+        const LWTHEME_DARKTEXT = 1 << 5;
     }
 }

components/style/gecko/selector_parser.rs

@@ -8,7 +8,7 @@ use crate::element_state::{DocumentState, ElementState};
 use crate::gecko_bindings::structs::RawServoSelectorList;
 use crate::gecko_bindings::sugar::ownership::{HasBoxFFI, HasFFI, HasSimpleFFI};
 use crate::invalidation::element::document_state::InvalidationMatchingData;
-use crate::selector_parser::{Direction, SelectorParser};
+use crate::selector_parser::{Direction, HorizontalDirection, SelectorParser};
 use crate::str::starts_with_ignore_ascii_case;
 use crate::string_cache::{Atom, Namespace, WeakAtom, WeakNamespace};
 use crate::values::{AtomIdent, AtomString};
@@ -174,8 +174,17 @@ impl NonTSPseudoClass {
     /// Get the document state flag associated with a pseudo-class, if any.
     pub fn document_state_flag(&self) -> DocumentState {
         match *self {
-            NonTSPseudoClass::MozLocaleDir(..) => DocumentState::NS_DOCUMENT_STATE_RTL_LOCALE,
+            NonTSPseudoClass::MozLocaleDir(ref dir) => {
-            NonTSPseudoClass::MozWindowInactive => DocumentState::NS_DOCUMENT_STATE_WINDOW_INACTIVE,
+                match dir.as_horizontal_direction() {
+                    Some(HorizontalDirection::Ltr) => DocumentState::LTR_LOCALE,
+                    Some(HorizontalDirection::Rtl) => DocumentState::RTL_LOCALE,
+                    None => DocumentState::empty(),
+                }
+            },
+            NonTSPseudoClass::MozWindowInactive => DocumentState::WINDOW_INACTIVE,
+            NonTSPseudoClass::MozLWTheme => DocumentState::LWTHEME,
+            NonTSPseudoClass::MozLWThemeBrightText => DocumentState::LWTHEME_BRIGHTTEXT,
+            NonTSPseudoClass::MozLWThemeDarkText => DocumentState::LWTHEME_DARKTEXT,
             _ => DocumentState::empty(),
         }
     }

components/style/gecko/wrapper.rs

@@ -39,11 +39,10 @@ use crate::gecko_bindings::bindings::Gecko_IsSignificantChild;
 use crate::gecko_bindings::bindings::Gecko_MatchLang;
 use crate::gecko_bindings::bindings::Gecko_UnsetDirtyStyleAttr;
 use crate::gecko_bindings::bindings::Gecko_UpdateAnimations;
-use crate::gecko_bindings::bindings::{Gecko_ElementState, Gecko_GetDocumentLWTheme};
+use crate::gecko_bindings::bindings::Gecko_ElementState;
 use crate::gecko_bindings::bindings::{Gecko_SetNodeFlags, Gecko_UnsetNodeFlags};
 use crate::gecko_bindings::structs;
 use crate::gecko_bindings::structs::nsChangeHint;
-use crate::gecko_bindings::structs::Document_DocumentTheme as DocumentTheme;
 use crate::gecko_bindings::structs::EffectCompositor_CascadeLevel as CascadeLevel;
 use crate::gecko_bindings::structs::ELEMENT_HANDLED_SNAPSHOT;
 use crate::gecko_bindings::structs::ELEMENT_HAS_ANIMATION_ONLY_DIRTY_DESCENDANTS_FOR_SERVO;
@@ -62,7 +61,7 @@ use crate::properties::animated_properties::{AnimationValue, AnimationValueMap};
 use crate::properties::{ComputedValues, LonghandId};
 use crate::properties::{Importance, PropertyDeclaration, PropertyDeclarationBlock};
 use crate::rule_tree::CascadeLevel as ServoCascadeLevel;
-use crate::selector_parser::{AttrValue, HorizontalDirection, Lang};
+use crate::selector_parser::{AttrValue, Lang};
 use crate::shared_lock::{Locked, SharedRwLock};
 use crate::string_cache::{Atom, Namespace, WeakAtom, WeakNamespace};
 use crate::stylist::CascadeData;
@@ -752,12 +751,6 @@ impl<'le> GeckoElement<'le> {
             .get_bool_flag(nsINode_BooleanFlag::ElementMayHaveStyle)
     }
 
-    #[inline]
-    fn document_theme(&self) -> DocumentTheme {
-        let node = self.as_node();
-        unsafe { Gecko_GetDocumentLWTheme(node.owner_doc().0) }
-    }
-
     /// Only safe to call on the main thread, with exclusive access to the
     /// element and its ancestors.
     ///
@@ -2033,39 +2026,24 @@ impl<'le> ::selectors::Element for GeckoElement<'le> {
                 bindings::Gecko_IsSelectListBox(self.0)
             },
             NonTSPseudoClass::MozIsHTML => self.is_html_element_in_html_document(),
-            NonTSPseudoClass::MozLWTheme => self.document_theme() != DocumentTheme::Doc_Theme_None,
+
-            NonTSPseudoClass::MozLWThemeBrightText => {
+            NonTSPseudoClass::MozLWTheme |
-                self.document_theme() == DocumentTheme::Doc_Theme_Bright
+            NonTSPseudoClass::MozLWThemeBrightText |
-            },
+            NonTSPseudoClass::MozLWThemeDarkText |
-            NonTSPseudoClass::MozLWThemeDarkText => {
+            NonTSPseudoClass::MozLocaleDir(..) |
-                self.document_theme() == DocumentTheme::Doc_Theme_Dark
-            },
             NonTSPseudoClass::MozWindowInactive => {
-                let state_bit = DocumentState::NS_DOCUMENT_STATE_WINDOW_INACTIVE;
+                let state_bit = pseudo_class.document_state_flag();
+                if state_bit.is_empty() {
+                    debug_assert!(matches!(pseudo_class, NonTSPseudoClass::MozLocaleDir(..)), "Only moz-locale-dir should ever return an empty state");
+                    return false;
+                }
                 if context.extra_data.document_state.intersects(state_bit) {
                     return !context.in_negation();
                 }
-
                 self.document_state().contains(state_bit)
             },
             NonTSPseudoClass::MozPlaceholder => false,
             NonTSPseudoClass::Lang(ref lang_arg) => self.match_element_lang(None, lang_arg),
-            NonTSPseudoClass::MozLocaleDir(ref dir) => {
-                let state_bit = DocumentState::NS_DOCUMENT_STATE_RTL_LOCALE;
-                if context.extra_data.document_state.intersects(state_bit) {
-                    // NOTE(emilio): We could still return false for values
-                    // other than "ltr" and "rtl", but we don't bother.
-                    return !context.in_negation();
-                }
-
-                let doc_is_rtl = self.document_state().contains(state_bit);
-
-                match dir.as_horizontal_direction() {
-                    Some(HorizontalDirection::Ltr) => !doc_is_rtl,
-                    Some(HorizontalDirection::Rtl) => doc_is_rtl,
-                    None => false,
-                }
-            },
         }
     }