Auto merge of #25717 - emilio:gecko-sync, r=emilio,nox

style: Sync changes from mozilla-central.

See individual commits for details. https://bugzilla.mozilla.org/show_bug.cgi?id=1614394

17 files changed, 178 insertions, 452 deletions

diff --git a/components/style/properties/cascade.rs b/components/style/properties/cascade.rs
index dd87916cf7d..50029da8479 100644
--- a/components/style/properties/cascade.rs
+++ b/components/style/properties/cascade.rs
@@ -25,7 +25,7 @@ use smallvec::SmallVec;
 use std::borrow::Cow;
 use std::cell::RefCell;
 use crate::style_adjuster::StyleAdjuster;
-use crate::values::computed;
+use crate::values::{computed, specified};
 
 /// We split the cascade in two phases: 'early' properties, and 'late'
 /// properties.
@@ -250,7 +250,7 @@ where
     let custom_properties = {
         let mut builder = CustomPropertiesBuilder::new(
             inherited_style.custom_properties(),
-            device.environment(),
+            device,
         );
 
         for (declaration, origin) in iter_declarations() {
@@ -263,8 +263,11 @@ where
         builder.build()
     };
 
+
+    let is_root_element =
+        pseudo.is_none() && element.map_or(false, |e| e.is_root());
+
     let mut context = computed::Context {
-        is_root_element: pseudo.is_none() && element.map_or(false, |e| e.is_root()),
         // We'd really like to own the rules here to avoid refcount traffic, but
         // animation's usage of `apply_declarations` make this tricky. See bug
         // 1375525.
@@ -275,6 +278,7 @@ where
             pseudo,
             Some(rules.clone()),
             custom_properties,
+            is_root_element,
         ),
         cached_system_font: None,
         in_media_query: false,
@@ -333,27 +337,37 @@ where
     context.builder.build()
 }
 
-fn should_ignore_declaration_when_ignoring_document_colors(
-    device: &Device,
+/// How should a declaration behave when ignoring document colors?
+enum DeclarationApplication {
+    /// We should apply the declaration.
+    Apply,
+    /// We should ignore the declaration.
+    Ignore,
+    /// We should apply the following declaration, only if any other declaration
+    /// hasn't set it before.
+    ApplyUnlessOverriden(PropertyDeclaration),
+}
+
+fn application_when_ignoring_colors(
+    builder: &StyleBuilder,
     longhand_id: LonghandId,
     origin: Origin,
-    pseudo: Option<&PseudoElement>,
-    declaration: &mut Cow<PropertyDeclaration>,
-) -> bool {
+    declaration: &PropertyDeclaration,
+) -> DeclarationApplication {
     if !longhand_id.ignored_when_document_colors_disabled() {
-        return false;
+        return DeclarationApplication::Apply;
     }
 
     let is_ua_or_user_rule = matches!(origin, Origin::User | Origin::UserAgent);
     if is_ua_or_user_rule {
-        return false;
+        return DeclarationApplication::Apply;
     }
 
     // Don't override background-color on ::-moz-color-swatch. It is set as an
     // author style (via the style attribute), but it's pretty important for it
     // to show up for obvious reasons :)
-    if pseudo.map_or(false, |p| p.is_color_swatch()) && longhand_id == LonghandId::BackgroundColor {
-        return false;
+    if builder.pseudo.map_or(false, |p| p.is_color_swatch()) && longhand_id == LonghandId::BackgroundColor {
+        return DeclarationApplication::Apply;
     }
 
     // Treat background-color a bit differently.  If the specified color is
@@ -365,26 +379,41 @@ fn should_ignore_declaration_when_ignoring_document_colors(
     // a background image, if we're ignoring document colors).
     // Here we check backplate status to decide if ignoring background-image
     // is the right decision.
-    {
-        let background_color = match **declaration {
-            PropertyDeclaration::BackgroundColor(ref color) => color,
-            // In the future, if/when we remove the backplate pref, we can remove this
-            // special case along with the 'ignored_when_colors_disabled=True' mako line
-            // for the "background-image" property.
-            #[cfg(feature = "gecko")]
-            PropertyDeclaration::BackgroundImage(..) => return !static_prefs::pref!("browser.display.permit_backplate"),
-            _ => return true,
-        };
-
-        if background_color.is_transparent() {
-            return false;
+    match *declaration {
+        PropertyDeclaration::BackgroundColor(ref color) => {
+            if color.is_transparent() {
+                return DeclarationApplication::Apply;
+            }
+            let color = builder.device.default_background_color();
+            DeclarationApplication::ApplyUnlessOverriden(
+                PropertyDeclaration::BackgroundColor(color.into())
+            )
         }
+        PropertyDeclaration::Color(ref color) => {
+            if color.0.is_transparent() {
+                return DeclarationApplication::Apply;
+            }
+            if builder.get_parent_inherited_text().clone_color().alpha != 0 {
+                return DeclarationApplication::Ignore;
+            }
+            let color = builder.device.default_color();
+            DeclarationApplication::ApplyUnlessOverriden(
+                PropertyDeclaration::Color(specified::ColorPropertyValue(color.into()))
+            )
+        },
+        // In the future, if/when we remove the backplate pref, we can remove this
+        // special case along with the 'ignored_when_colors_disabled=True' mako line
+        // for the "background-image" property.
+        #[cfg(feature = "gecko")]
+        PropertyDeclaration::BackgroundImage(..) => {
+            if static_prefs::pref!("browser.display.permit_backplate") {
+                DeclarationApplication::Apply
+            } else {
+                DeclarationApplication::Ignore
+            }
+        },
+        _ => DeclarationApplication::Ignore,
     }
-
-    let color = device.default_background_color();
-    *declaration.to_mut() = PropertyDeclaration::BackgroundColor(color.into());
-
-    false
 }
 
 struct Cascade<'a, 'b: 'a> {
@@ -424,7 +453,7 @@ impl<'a, 'b: 'a> Cascade<'a, 'b> {
             declaration.id,
             self.context.builder.custom_properties.as_ref(),
             self.context.quirks_mode,
-            self.context.device().environment(),
+            self.context.device(),
         ))
     }
 
@@ -461,6 +490,8 @@ impl<'a, 'b: 'a> Cascade<'a, 'b> {
         );
 
         let ignore_colors = !self.context.builder.device.use_document_colors();
+        let mut declarations_to_apply_unless_overriden =
+            SmallVec::<[PropertyDeclaration; 2]>::new();
 
         for (declaration, origin) in declarations {
             let declaration_id = declaration.id();
@@ -502,21 +533,25 @@ impl<'a, 'b: 'a> Cascade<'a, 'b> {
                 continue;
             }
 
-            let mut declaration = self.substitute_variables_if_needed(declaration);
+            let declaration = self.substitute_variables_if_needed(declaration);
 
-            // When document colors are disabled, skip properties that are
-            // marked as ignored in that mode, unless they come from a UA or
-            // user style sheet.
+            // When document colors are disabled, do special handling of
+            // properties that are marked as ignored in that mode.
             if ignore_colors {
-                let should_ignore = should_ignore_declaration_when_ignoring_document_colors(
-                    self.context.builder.device,
+                let application = application_when_ignoring_colors(
+                    &self.context.builder,
                     longhand_id,
                     origin,
-                    self.context.builder.pseudo,
-                    &mut declaration,
+                    &declaration,
                 );
-                if should_ignore {
-                    continue;
+
+                match application {
+                    DeclarationApplication::Ignore => continue,
+                    DeclarationApplication::Apply => {},
+                    DeclarationApplication::ApplyUnlessOverriden(decl) => {
+                        declarations_to_apply_unless_overriden.push(decl);
+                        continue;
+                    }
                 }
             }
 
@@ -554,6 +589,20 @@ impl<'a, 'b: 'a> Cascade<'a, 'b> {
             self.apply_declaration(longhand_id, &*declaration);
         }
 
+        if ignore_colors {
+            for declaration in declarations_to_apply_unless_overriden.iter() {
+                let longhand_id = match declaration.id() {
+                    PropertyDeclarationId::Longhand(id) => id,
+                    PropertyDeclarationId::Custom(..) => unreachable!(),
+                };
+                debug_assert!(!longhand_id.is_logical());
+                if self.seen.contains(longhand_id) {
+                    continue;
+                }
+                self.apply_declaration(longhand_id, declaration);
+            }
+        }
+
         if Phase::is_early() {
             self.fixup_font_stuff();
             self.compute_writing_mode();
diff --git a/components/style/properties/computed_value_flags.rs b/components/style/properties/computed_value_flags.rs
index a86f8a4da3a..4363f3f36e9 100644
--- a/components/style/properties/computed_value_flags.rs
+++ b/components/style/properties/computed_value_flags.rs
@@ -11,6 +11,7 @@ bitflags! {
     /// anonymous boxes, see StyleBuilder::for_inheritance and its callsites.
     /// If we ever want to add some flags that shouldn't inherit for them,
     /// we might want to add a function to handle this.
+    #[repr(C)]
     pub struct ComputedValueFlags: u16 {
         /// Whether the style or any of the ancestors has a text-decoration-line
         /// property that should get propagated to descendants.
@@ -63,6 +64,9 @@ bitflags! {
         ///
         /// Only used in Servo.
         const CAN_BE_FRAGMENTED = 1 << 10;
+
+        /// Whether this style is the style of the document element.
+        const IS_ROOT_ELEMENT_STYLE = 1 << 11;
     }
 }
 
@@ -71,9 +75,9 @@ impl ComputedValueFlags {
     #[inline]
     fn inherited_flags() -> Self {
         ComputedValueFlags::IS_RELEVANT_LINK_VISITED |
-        ComputedValueFlags::CAN_BE_FRAGMENTED |
-        ComputedValueFlags::IS_IN_PSEUDO_ELEMENT_SUBTREE |
-        ComputedValueFlags::HAS_TEXT_DECORATION_LINES
+            ComputedValueFlags::CAN_BE_FRAGMENTED |
+            ComputedValueFlags::IS_IN_PSEUDO_ELEMENT_SUBTREE |
+            ComputedValueFlags::HAS_TEXT_DECORATION_LINES
     }
 
     /// Flags that may be propagated to descendants.
@@ -97,22 +101,3 @@ impl ComputedValueFlags {
         self & Self::maybe_inherited_flags()
     }
 }
-
-/// Asserts that the relevant servo and Gecko representations match.
-#[cfg(feature = "gecko")]
-#[inline]
-pub fn assert_match() {
-    use crate::gecko_bindings::structs;
-    macro_rules! assert_bit {
-        ($rust:ident, $cpp:ident) => {
-            debug_assert_eq!(ComputedValueFlags::$rust.bits, structs::$cpp);
-        }
-    }
-
-    assert_bit!(HAS_TEXT_DECORATION_LINES, ComputedStyleBit_HasTextDecorationLines);
-    assert_bit!(IS_IN_PSEUDO_ELEMENT_SUBTREE, ComputedStyleBit_HasPseudoElementData);
-    assert_bit!(SHOULD_SUPPRESS_LINEBREAK, ComputedStyleBit_SuppressLineBreak);
-    assert_bit!(IS_TEXT_COMBINED, ComputedStyleBit_IsTextCombined);
-    assert_bit!(IS_RELEVANT_LINK_VISITED, ComputedStyleBit_RelevantLinkVisited);
-    assert_bit!(DEPENDS_ON_FONT_METRICS, ComputedStyleBit_DependsOnFontMetrics);
-}
diff --git a/components/style/properties/declaration_block.rs b/components/style/properties/declaration_block.rs
index 90dec0a47d7..53b483887ce 100644
--- a/components/style/properties/declaration_block.rs
+++ b/components/style/properties/declaration_block.rs
@@ -8,7 +8,7 @@
 
 use super::*;
 use crate::context::QuirksMode;
-use crate::custom_properties::{CssEnvironment, CustomPropertiesBuilder};
+use crate::custom_properties::CustomPropertiesBuilder;
 use crate::error_reporting::{ContextualParseError, ParseErrorReporter};
 use crate::parser::ParserContext;
 use crate::properties::animated_properties::{AnimationValue, AnimationValueMap};
@@ -778,6 +778,7 @@ impl PropertyDeclarationBlock {
         dest: &mut CssStringWriter,
         computed_values: Option<&ComputedValues>,
         custom_properties_block: Option<&PropertyDeclarationBlock>,
+        device: &Device,
     ) -> fmt::Result {
         if let Ok(shorthand) = property.as_shorthand() {
             return self.shorthand_to_css(shorthand, dest);
@@ -790,19 +791,13 @@ impl PropertyDeclarationBlock {
             None => return Err(fmt::Error),
         };
 
-        // TODO(emilio): When we implement any environment variable without
-        // hard-coding the values we're going to need to get something
-        // meaningful out of here... All this code path is so terribly hacky
-        // ;_;.
-        let env = CssEnvironment;
-
         let custom_properties = if let Some(cv) = computed_values {
             // If there are extra custom properties for this declaration block,
             // factor them in too.
             if let Some(block) = custom_properties_block {
                 // FIXME(emilio): This is not super-efficient here, and all this
                 // feels like a hack anyway...
-                block.cascade_custom_properties(cv.custom_properties(), &env)
+                block.cascade_custom_properties(cv.custom_properties(), device)
             } else {
                 cv.custom_properties().cloned()
             }
@@ -825,7 +820,7 @@ impl PropertyDeclarationBlock {
                         declaration.id,
                         custom_properties.as_ref(),
                         QuirksMode::NoQuirks,
-                        &env,
+                        device,
                     )
                     .to_css(dest)
             },
@@ -873,7 +868,7 @@ impl PropertyDeclarationBlock {
     ) -> Option<Arc<crate::custom_properties::CustomPropertiesMap>> {
         self.cascade_custom_properties(
             context.style().custom_properties(),
-            context.device().environment(),
+            context.device(),
         )
     }
 
@@ -883,9 +878,9 @@ impl PropertyDeclarationBlock {
     fn cascade_custom_properties(
         &self,
         inherited_custom_properties: Option<&Arc<crate::custom_properties::CustomPropertiesMap>>,
-        environment: &CssEnvironment,
+        device: &Device,
     ) -> Option<Arc<crate::custom_properties::CustomPropertiesMap>> {
-        let mut builder = CustomPropertiesBuilder::new(inherited_custom_properties, environment);
+        let mut builder = CustomPropertiesBuilder::new(inherited_custom_properties, device);
 
         for declaration in self.normal_declaration_iter() {
             if let PropertyDeclaration::Custom(ref declaration) = *declaration {
diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index 14262e7a074..6cfb4c859b4 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -12,6 +12,7 @@
 
 use crate::Atom;
 use app_units::Au;
+use crate::computed_value_flags::*;
 use crate::custom_properties::CustomPropertiesMap;
 use crate::gecko_bindings::bindings;
 % for style_struct in data.style_structs:
@@ -24,28 +25,20 @@ use crate::gecko_bindings::bindings::Gecko_CopyCounterStyle;
 use crate::gecko_bindings::bindings::Gecko_CopyCursorArrayFrom;
 use crate::gecko_bindings::bindings::Gecko_CopyFontFamilyFrom;
 use crate::gecko_bindings::bindings::Gecko_CopyImageValueFrom;
-use crate::gecko_bindings::bindings::Gecko_CopyListStyleImageFrom;
 use crate::gecko_bindings::bindings::Gecko_EnsureImageLayersLength;
-use crate::gecko_bindings::bindings::Gecko_SetCursorArrayLength;
-use crate::gecko_bindings::bindings::Gecko_SetCursorImageValue;
 use crate::gecko_bindings::bindings::Gecko_nsStyleFont_SetLang;
 use crate::gecko_bindings::bindings::Gecko_nsStyleFont_CopyLangFrom;
-use crate::gecko_bindings::bindings::Gecko_SetListStyleImageNone;
-use crate::gecko_bindings::bindings::Gecko_SetListStyleImageImageValue;
 use crate::gecko_bindings::bindings::Gecko_SetNullImageValue;
 use crate::gecko_bindings::structs;
 use crate::gecko_bindings::structs::nsCSSPropertyID;
 use crate::gecko_bindings::structs::mozilla::PseudoStyleType;
-use crate::gecko_bindings::sugar::refptr::RefPtr;
 use crate::gecko::values::round_border_to_device_pixels;
 use crate::logical_geometry::WritingMode;
 use crate::media_queries::Device;
-use crate::properties::computed_value_flags::*;
 use crate::properties::longhands;
 use crate::rule_tree::StrongRuleNode;
 use crate::selector_parser::PseudoElement;
 use servo_arc::{Arc, RawOffsetArc, UniqueArc};
-use std::marker::PhantomData;
 use std::mem::{forget, MaybeUninit};
 use std::{cmp, ops, ptr};
 use crate::values::{self, CustomIdent, Either, KeyframesName, None_};
@@ -55,8 +48,6 @@ use crate::values::computed::BorderStyle;
 use crate::values::computed::font::FontSize;
 use crate::values::generics::column::ColumnCount;
 use crate::values::generics::image::ImageLayer;
-use crate::values::generics::transform::TransformStyle;
-use crate::values::generics::url::UrlOrNone;
 
 
 pub mod style_structs {
@@ -959,48 +950,16 @@ fn static_assert() {
 
 <% skip_position_longhands = " ".join(x.ident for x in SIDES) %>
 <%self:impl_trait style_struct_name="Position"
-                  skip_longhands="${skip_position_longhands}
-                                  align-content justify-content align-self
-                                  justify-self align-items justify-items
-                                  grid-auto-flow">
+                  skip_longhands="${skip_position_longhands} grid-auto-flow">
     % for side in SIDES:
     <% impl_split_style_coord(side.ident, "mOffset", side.index) %>
     % endfor
-
-    % for kind in ["align", "justify"]:
-    ${impl_simple_type_with_conversion(kind + "_content")}
-    ${impl_simple_type_with_conversion(kind + "_self")}
-    % endfor
-    ${impl_simple_type_with_conversion("align_items")}
-
-    pub fn set_justify_items(&mut self, v: longhands::justify_items::computed_value::T) {
-        self.gecko.mSpecifiedJustifyItems = v.specified.into();
-        self.set_computed_justify_items(v.computed);
-    }
-
+    ${impl_simple_type_with_conversion("grid_auto_flow")}
     pub fn set_computed_justify_items(&mut self, v: values::specified::JustifyItems) {
         debug_assert_ne!(v.0, crate::values::specified::align::AlignFlags::LEGACY);
-        self.gecko.mJustifyItems = v.into();
+        self.gecko.mJustifyItems.computed = v;
     }
 
-    pub fn reset_justify_items(&mut self, reset_style: &Self) {
-        self.gecko.mJustifyItems = reset_style.gecko.mJustifyItems;
-        self.gecko.mSpecifiedJustifyItems = reset_style.gecko.mSpecifiedJustifyItems;
-    }
-
-    pub fn copy_justify_items_from(&mut self, other: &Self) {
-        self.gecko.mJustifyItems = other.gecko.mJustifyItems;
-        self.gecko.mSpecifiedJustifyItems = other.gecko.mJustifyItems;
-    }
-
-    pub fn clone_justify_items(&self) -> longhands::justify_items::computed_value::T {
-        longhands::justify_items::computed_value::T {
-            computed: self.gecko.mJustifyItems.into(),
-            specified: self.gecko.mSpecifiedJustifyItems.into(),
-        }
-    }
-
-    ${impl_simple_type_with_conversion("grid_auto_flow")}
 </%self:impl_trait>
 
 <% skip_outline_longhands = " ".join("outline-style outline-width".split() +
@@ -1507,7 +1466,7 @@ fn static_assert() {
                           animation-iteration-count animation-timing-function
                           clear transition-duration transition-delay
                           transition-timing-function transition-property
-                          transform-style shape-outside -webkit-line-clamp""" %>
+                          shape-outside -webkit-line-clamp""" %>
 <%self:impl_trait style_struct_name="Box" skip_longhands="${skip_box_longhands}">
     #[inline]
     pub fn set_display(&mut self, v: longhands::display::computed_value::T) {
@@ -1664,25 +1623,6 @@ fn static_assert() {
         self.copy_transition_property_from(other)
     }
 
-    // Hand-written because the Mako helpers transform `Preserve3d` into `PRESERVE3D`.
-    pub fn set_transform_style(&mut self, v: TransformStyle) {
-        self.gecko.mTransformStyle = match v {
-            TransformStyle::Flat => structs::NS_STYLE_TRANSFORM_STYLE_FLAT as u8,
-            TransformStyle::Preserve3d => structs::NS_STYLE_TRANSFORM_STYLE_PRESERVE_3D as u8,
-        };
-    }
-
-    // Hand-written because the Mako helpers transform `Preserve3d` into `PRESERVE3D`.
-    pub fn clone_transform_style(&self) -> TransformStyle {
-        match self.gecko.mTransformStyle as u32 {
-            structs::NS_STYLE_TRANSFORM_STYLE_FLAT => TransformStyle::Flat,
-            structs::NS_STYLE_TRANSFORM_STYLE_PRESERVE_3D => TransformStyle::Preserve3d,
-            _ => panic!("illegal transform style"),
-        }
-    }
-
-    ${impl_simple_copy('transform_style', 'mTransformStyle')}
-
     ${impl_transition_count('property', 'Property')}
 
     pub fn animations_equals(&self, other: &Self) -> bool {
@@ -2162,57 +2102,20 @@ fn static_assert() {
     <% impl_simple_image_array_property("blend_mode", "background", "mImage", "mBlendMode", "Background") %>
 </%self:impl_trait>
 
-<%self:impl_trait style_struct_name="List"
-                  skip_longhands="list-style-image list-style-type">
-
-    pub fn set_list_style_image(&mut self, image: longhands::list_style_image::computed_value::T) {
-        match image {
-            UrlOrNone::None => {
-                unsafe {
-                    Gecko_SetListStyleImageNone(&mut *self.gecko);
-                }
-            }
-            UrlOrNone::Url(ref url) => {
-                unsafe {
-                    Gecko_SetListStyleImageImageValue(&mut *self.gecko, url);
-                }
-            }
-        }
-    }
-
-    pub fn copy_list_style_image_from(&mut self, other: &Self) {
-        unsafe { Gecko_CopyListStyleImageFrom(&mut *self.gecko, &*other.gecko); }
-    }
-
-    pub fn reset_list_style_image(&mut self, other: &Self) {
-        self.copy_list_style_image_from(other)
-    }
-
-    pub fn clone_list_style_image(&self) -> longhands::list_style_image::computed_value::T {
-        if self.gecko.mListStyleImage.mRawPtr.is_null() {
-            return UrlOrNone::None;
-        }
-
-        unsafe {
-            let ref gecko_image_request = *self.gecko.mListStyleImage.mRawPtr;
-            UrlOrNone::Url(ComputedImageUrl::from_image_request(gecko_image_request))
-        }
-    }
-
+<%self:impl_trait style_struct_name="List" skip_longhands="list-style-type">
     pub fn set_list_style_type(&mut self, v: longhands::list_style_type::computed_value::T) {
-        use crate::gecko_bindings::bindings::Gecko_SetCounterStyleToName;
-        use crate::gecko_bindings::bindings::Gecko_SetCounterStyleToString;
         use nsstring::{nsACString, nsCStr};
         use self::longhands::list_style_type::computed_value::T;
         match v {
             T::None => unsafe {
-                Gecko_SetCounterStyleToName(&mut self.gecko.mCounterStyle,
-                                            atom!("none").into_addrefed());
+                bindings::Gecko_SetCounterStyleToNone(&mut self.gecko.mCounterStyle)
             }
             T::CounterStyle(s) => s.to_gecko_value(&mut self.gecko.mCounterStyle),
             T::String(s) => unsafe {
-                Gecko_SetCounterStyleToString(&mut self.gecko.mCounterStyle,
-                                              &nsCStr::from(&s) as &nsACString)
+                bindings::Gecko_SetCounterStyleToString(
+                    &mut self.gecko.mCounterStyle,
+                    &nsCStr::from(&s) as &nsACString,
+                )
             }
         }
     }
@@ -2488,14 +2391,11 @@ clip-path
     pub fn set_cursor(&mut self, v: longhands::cursor::computed_value::T) {
         self.gecko.mCursor = v.keyword;
         unsafe {
-            Gecko_SetCursorArrayLength(&mut *self.gecko, v.images.len());
+            bindings::Gecko_SetCursorArrayCapacity(&mut *self.gecko, v.images.len());
         }
         for i in 0..v.images.len() {
             unsafe {
-                Gecko_SetCursorImageValue(
-                    &mut self.gecko.mCursorImages[i],
-                    &v.images[i].url
-                );
+                bindings::Gecko_AppendCursorImage(&mut *self.gecko, &v.images[i].url);
             }
 
             match v.images[i].hotspot {
@@ -2528,10 +2428,7 @@ clip-path
         let keyword = self.gecko.mCursor;
 
         let images = self.gecko.mCursorImages.iter().map(|gecko_cursor_image| {
-            let url = unsafe {
-                let gecko_image_request = gecko_cursor_image.mImage.mRawPtr.as_ref().unwrap();
-                ComputedImageUrl::from_image_request(&gecko_image_request)
-            };
+            let url = gecko_cursor_image.mImage.clone();
 
             let hotspot =
                 if gecko_cursor_image.mHaveHotspot {
@@ -2580,236 +2477,9 @@ clip-path
     ${impl_simple('column_rule_style', 'mColumnRuleStyle')}
 </%self:impl_trait>
 
-<%self:impl_trait style_struct_name="Counters" skip_longhands="content">
+<%self:impl_trait style_struct_name="Counters">
     pub fn ineffective_content_property(&self) -> bool {
-        self.gecko.mContents.is_empty()
-    }
-
-    pub fn set_content(&mut self, v: longhands::content::computed_value::T) {
-        use crate::values::CustomIdent;
-        use crate::values::generics::counters::{Content, ContentItem};
-        use crate::values::generics::CounterStyle;
-        use crate::gecko_bindings::structs::nsStyleContentData;
-        use crate::gecko_bindings::structs::nsStyleContentAttr;
-        use crate::gecko_bindings::structs::StyleContentType;
-        use crate::gecko_bindings::bindings::Gecko_ClearAndResizeStyleContents;
-
-        // Converts a string as utf16, and returns an owned, zero-terminated raw buffer.
-        fn as_utf16_and_forget(s: &str) -> *mut u16 {
-            use std::mem;
-            let mut vec = s.encode_utf16().collect::<Vec<_>>();
-            vec.push(0u16);
-            let ptr = vec.as_mut_ptr();
-            mem::forget(vec);
-            ptr
-        }
-
-        fn set_counter_function(
-            data: &mut nsStyleContentData,
-            content_type: StyleContentType,
-            name: CustomIdent,
-            sep: &str,
-            style: CounterStyle,
-        ) {
-            debug_assert!(content_type == StyleContentType::Counter ||
-                          content_type == StyleContentType::Counters);
-            let counter_func = unsafe {
-                bindings::Gecko_SetCounterFunction(data, content_type).as_mut().unwrap()
-            };
-            counter_func.mIdent.set_move(unsafe {
-                RefPtr::from_addrefed(name.0.into_addrefed())
-            });
-            if content_type == StyleContentType::Counters {
-                counter_func.mSeparator.assign_str(sep);
-            }
-            style.to_gecko_value(&mut counter_func.mCounterStyle);
-        }
-
-        match v {
-            Content::None |
-            Content::Normal => {
-                // Ensure destructors run, otherwise we could leak.
-                if !self.gecko.mContents.is_empty() {
-                    unsafe {
-                        Gecko_ClearAndResizeStyleContents(&mut *self.gecko, 0);
-                    }
-                }
-            },
-            Content::MozAltContent => {
-                unsafe {
-                    Gecko_ClearAndResizeStyleContents(&mut *self.gecko, 1);
-                    *self.gecko.mContents[0].mContent.mString.as_mut() = ptr::null_mut();
-                }
-                self.gecko.mContents[0].mType = StyleContentType::AltContent;
-            },
-            Content::Items(items) => {
-                unsafe {
-                    Gecko_ClearAndResizeStyleContents(&mut *self.gecko,
-                                                      items.len() as u32);
-                }
-                for (i, item) in items.into_vec().into_iter().enumerate() {
-                    // NB: Gecko compares the mString value if type is not image
-                    // or URI independently of whatever gets there. In the quote
-                    // cases, they set it to null, so do the same here.
-                    unsafe {
-                        *self.gecko.mContents[i].mContent.mString.as_mut() = ptr::null_mut();
-                    }
-                    match item {
-                        ContentItem::String(ref value) => {
-                            self.gecko.mContents[i].mType = StyleContentType::String;
-                            unsafe {
-                                // NB: we share allocators, so doing this is fine.
-                                *self.gecko.mContents[i].mContent.mString.as_mut() =
-                                    as_utf16_and_forget(&value);
-                            }
-                        }
-                        ContentItem::Attr(ref attr) => {
-                            self.gecko.mContents[i].mType = StyleContentType::Attr;
-                            unsafe {
-                                // NB: we share allocators, so doing this is fine.
-                                let maybe_ns = attr.namespace.clone();
-                                let attr_struct = Box::new(nsStyleContentAttr {
-                                    mName: structs::RefPtr {
-                                        mRawPtr: attr.attribute.clone().into_addrefed(),
-                                        _phantom_0: PhantomData,
-                                    },
-                                    mNamespaceURL: structs::RefPtr {
-                                        mRawPtr: maybe_ns.map_or(ptr::null_mut(), |x| (x.1).0.into_addrefed()),
-                                        _phantom_0: PhantomData,
-                                    },
-                                });
-                                *self.gecko.mContents[i].mContent.mAttr.as_mut() =
-                                    Box::into_raw(attr_struct);
-                            }
-                        }
-                        ContentItem::OpenQuote
-                            => self.gecko.mContents[i].mType = StyleContentType::OpenQuote,
-                        ContentItem::CloseQuote
-                            => self.gecko.mContents[i].mType = StyleContentType::CloseQuote,
-                        ContentItem::NoOpenQuote
-                            => self.gecko.mContents[i].mType = StyleContentType::NoOpenQuote,
-                        ContentItem::NoCloseQuote
-                            => self.gecko.mContents[i].mType = StyleContentType::NoCloseQuote,
-                        ContentItem::Counter(name, style) => {
-                            set_counter_function(
-                                &mut self.gecko.mContents[i],
-                                StyleContentType::Counter,
-                                name,
-                                "",
-                                style,
-                            );
-                        }
-                        ContentItem::Counters(name, sep, style) => {
-                            set_counter_function(
-                                &mut self.gecko.mContents[i],
-                                StyleContentType::Counters,
-                                name,
-                                &sep,
-                                style,
-                            );
-                        }
-                        ContentItem::Url(ref url) => {
-                            unsafe {
-                                bindings::Gecko_SetContentDataImageValue(
-                                    &mut self.gecko.mContents[i],
-                                    url,
-                                )
-                            }
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    pub fn copy_content_from(&mut self, other: &Self) {
-        use crate::gecko_bindings::bindings::Gecko_CopyStyleContentsFrom;
-        unsafe {
-            Gecko_CopyStyleContentsFrom(&mut *self.gecko, &*other.gecko)
-        }
-    }
-
-    pub fn reset_content(&mut self, other: &Self) {
-        self.copy_content_from(other)
-    }
-
-    pub fn clone_content(&self) -> longhands::content::computed_value::T {
-        use {Atom, Namespace};
-        use crate::gecko::conversions::string_from_chars_pointer;
-        use crate::gecko_bindings::structs::StyleContentType;
-        use crate::values::generics::counters::{Content, ContentItem};
-        use crate::values::{CustomIdent, Either};
-        use crate::values::generics::CounterStyle;
-        use crate::values::specified::Attr;
-
-        if self.gecko.mContents.is_empty() {
-            return Content::None;
-        }
-
-        if self.gecko.mContents.len() == 1 &&
-           self.gecko.mContents[0].mType == StyleContentType::AltContent {
-            return Content::MozAltContent;
-        }
-
-        Content::Items(
-            self.gecko.mContents.iter().map(|gecko_content| {
-                match gecko_content.mType {
-                    StyleContentType::OpenQuote => ContentItem::OpenQuote,
-                    StyleContentType::CloseQuote => ContentItem::CloseQuote,
-                    StyleContentType::NoOpenQuote => ContentItem::NoOpenQuote,
-                    StyleContentType::NoCloseQuote => ContentItem::NoCloseQuote,
-                    StyleContentType::String => {
-                        let gecko_chars = unsafe { gecko_content.mContent.mString.as_ref() };
-                        let string = unsafe { string_from_chars_pointer(*gecko_chars) };
-                        ContentItem::String(string.into_boxed_str())
-                    },
-                    StyleContentType::Attr => {
-                        let (namespace, attribute) = unsafe {
-                            let s = &**gecko_content.mContent.mAttr.as_ref();
-                            let ns = if s.mNamespaceURL.mRawPtr.is_null() {
-                                None
-                            } else {
-                                // FIXME(bholley): We don't have any way to get the prefix here. :-(
-                                let prefix = atom!("");
-                                Some((prefix, Namespace(Atom::from_raw(s.mNamespaceURL.mRawPtr))))
-                            };
-                            (ns, Atom::from_raw(s.mName.mRawPtr))
-                        };
-                        ContentItem::Attr(Attr { namespace, attribute })
-                    },
-                    StyleContentType::Counter | StyleContentType::Counters => {
-                        let gecko_function =
-                            unsafe { &**gecko_content.mContent.mCounters.as_ref() };
-                        let ident = CustomIdent(unsafe {
-                            Atom::from_raw(gecko_function.mIdent.mRawPtr)
-                        });
-                        let style =
-                            CounterStyle::from_gecko_value(&gecko_function.mCounterStyle);
-                        let style = match style {
-                            Either::First(counter_style) => counter_style,
-                            Either::Second(_) =>
-                                unreachable!("counter function shouldn't have single string type"),
-                        };
-                        if gecko_content.mType == StyleContentType::Counter {
-                            ContentItem::Counter(ident, style)
-                        } else {
-                            let separator = gecko_function.mSeparator.to_string();
-                            ContentItem::Counters(ident, separator.into_boxed_str(), style)
-                        }
-                    },
-                    StyleContentType::Image => {
-                        unsafe {
-                            let gecko_image_request =
-                                &**gecko_content.mContent.mImage.as_ref();
-                            ContentItem::Url(
-                                ComputedImageUrl::from_image_request(gecko_image_request)
-                            )
-                        }
-                    },
-                    _ => panic!("Found unexpected value in style struct for content property"),
-                }
-            }).collect::<Vec<_>>().into_boxed_slice()
-        )
+        !self.gecko.mContent.is_items()
     }
 </%self:impl_trait>
 
diff --git a/components/style/properties/helpers.mako.rs b/components/style/properties/helpers.mako.rs
index 4d3895440d5..7a25b2569ea 100644
--- a/components/style/properties/helpers.mako.rs
+++ b/components/style/properties/helpers.mako.rs
@@ -563,6 +563,7 @@
                 Copy,
                 Debug,
                 Eq,
+                FromPrimitive,
                 Hash,
                 MallocSizeOf,
                 Parse,
@@ -762,7 +763,7 @@
         % endif
         pub mod computed_value {
             #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
-            #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToCss, ToResolvedValue)]
+            #[derive(Clone, Copy, Debug, Eq, FromPrimitive, MallocSizeOf, PartialEq, ToCss, ToResolvedValue)]
             % if not extra_specified:
             #[derive(Parse, SpecifiedValueInfo, ToComputedValue, ToShmem)]
             % endif
diff --git a/components/style/properties/helpers/animated_properties.mako.rs b/components/style/properties/helpers/animated_properties.mako.rs
index c81e186a129..84f843ec728 100644
--- a/components/style/properties/helpers/animated_properties.mako.rs
+++ b/components/style/properties/helpers/animated_properties.mako.rs
@@ -507,7 +507,7 @@ impl AnimationValue {
                         declaration.id,
                         custom_properties,
                         context.quirks_mode,
-                        context.device().environment(),
+                        context.device(),
                     )
                 };
                 return AnimationValue::from_declaration(
diff --git a/components/style/properties/longhands/box.mako.rs b/components/style/properties/longhands/box.mako.rs
index fba2fac66dc..90c8dc539d8 100644
--- a/components/style/properties/longhands/box.mako.rs
+++ b/components/style/properties/longhands/box.mako.rs
@@ -47,6 +47,7 @@ ${helpers.single_keyword(
     values="static absolute relative fixed ${'sticky' if engine in ['gecko', 'servo-2013'] else ''}"
     engines="gecko servo-2013 servo-2020"
     animation_value_type="discrete"
+    gecko_enum_prefix="StylePositionProperty"
     flags="CREATES_STACKING_CONTEXT ABSPOS_CB"
     spec="https://drafts.csswg.org/css-position/#position-property"
     servo_restyle_damage="rebuild_and_reflow"
@@ -452,6 +453,7 @@ ${helpers.single_keyword(
     engines="gecko",
     spec="https://drafts.csswg.org/cssom-view/#propdef-scroll-behavior",
     animation_value_type="discrete",
+    gecko_enum_prefix="StyleScrollBehavior",
 )}
 
 ${helpers.predefined_type(
@@ -472,13 +474,15 @@ ${helpers.predefined_type(
     animation_value_type="discrete",
 )}
 
-% for axis in ["x", "y"]:
+% for (axis, logical) in ALL_AXES:
     ${helpers.predefined_type(
         "overscroll-behavior-" + axis,
         "OverscrollBehavior",
         "computed::OverscrollBehavior::Auto",
         engines="gecko",
         needs_context=False,
+        logical_group="overscroll-behavior",
+        logical=logical,
         gecko_pref="layout.css.overscroll-behavior.enabled",
         spec="https://wicg.github.io/overscroll-behavior/#overscroll-behavior-properties",
         animation_value_type="discrete",
@@ -589,7 +593,7 @@ ${helpers.single_keyword(
 ${helpers.predefined_type(
     "transform-style",
     "TransformStyle",
-    "computed::TransformStyle::" + ("Flat" if engine == "gecko" else "Auto"),
+    "computed::TransformStyle::Flat",
     engines="gecko servo-2013 servo-2020",
     servo_2020_pref="layout.2020.unimplemented",
     spec="https://drafts.csswg.org/css-transforms-2/#transform-style-property",
diff --git a/components/style/properties/longhands/column.mako.rs b/components/style/properties/longhands/column.mako.rs
index 8b49679abf7..1974e82d137 100644
--- a/components/style/properties/longhands/column.mako.rs
+++ b/components/style/properties/longhands/column.mako.rs
@@ -13,7 +13,7 @@ ${helpers.predefined_type(
     engines="gecko servo-2013 servo-2020",
     servo_2020_pref="layout.2020.unimplemented",
     initial_specified_value="specified::length::NonNegativeLengthOrAuto::auto()",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     animation_value_type="NonNegativeLengthOrAuto",
     servo_2013_pref="layout.columns.enabled",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-width",
@@ -29,7 +29,7 @@ ${helpers.predefined_type(
     initial_specified_value="specified::ColumnCount::auto()",
     servo_2013_pref="layout.columns.enabled",
     animation_value_type="AnimatedColumnCount",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-count",
     servo_restyle_damage="rebuild_and_reflow",
 )}
@@ -38,7 +38,7 @@ ${helpers.single_keyword(
     "column-fill",
     "balance auto",
     engines="gecko",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     animation_value_type="discrete",
     gecko_enum_prefix="StyleColumnFill",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-fill",
@@ -53,7 +53,7 @@ ${helpers.predefined_type(
     computed_type="crate::values::computed::NonNegativeLength",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-rule-width",
     animation_value_type="NonNegativeLength",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
 )}
 
 // https://drafts.csswg.org/css-multicol-1/#crc
@@ -64,22 +64,19 @@ ${helpers.predefined_type(
     engines="gecko",
     initial_specified_value="specified::Color::currentcolor()",
     animation_value_type="AnimatedColor",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     ignored_when_colors_disabled=True,
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-rule-color",
 )}
 
-// FIXME: Remove enabled_in="ua" once column-span is enabled on nightly (bug 1423383).
 ${helpers.single_keyword(
     "column-span",
     "none all",
     engines="gecko",
     animation_value_type="discrete",
     gecko_enum_prefix="StyleColumnSpan",
-    gecko_pref="layout.css.column-span.enabled",
-    enabled_in="ua",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-span",
-    extra_prefixes="moz:layout.css.column-span.enabled",
+    extra_prefixes="moz:layout.css.prefixes.columns",
 )}
 
 ${helpers.predefined_type(
@@ -89,7 +86,7 @@ ${helpers.predefined_type(
     engines="gecko",
     needs_context=False,
     initial_specified_value="specified::BorderStyle::None",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     animation_value_type="discrete",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-rule-style",
 )}
diff --git a/components/style/properties/longhands/inherited_box.mako.rs b/components/style/properties/longhands/inherited_box.mako.rs
index 78c2e6023ee..e8f3a0a45d9 100644
--- a/components/style/properties/longhands/inherited_box.mako.rs
+++ b/components/style/properties/longhands/inherited_box.mako.rs
@@ -43,7 +43,7 @@ ${helpers.single_keyword(
     servo_2020_pref="layout.2020.unimplemented",
     animation_value_type="none",
     spec="https://drafts.csswg.org/css-writing-modes/#propdef-direction",
-    needs_conversion=True,
+    gecko_enum_prefix="StyleDirection",
     servo_restyle_damage="rebuild_and_reflow",
 )}
 
@@ -78,6 +78,7 @@ ${helpers.single_keyword(
     extra_servo_2013_values="pixelated",
     extra_servo_2020_values="pixelated",
     gecko_aliases="-moz-crisp-edges=crisp-edges",
+    gecko_enum_prefix="StyleImageRendering",
     animation_value_type="discrete",
     spec="https://drafts.csswg.org/css-images/#propdef-image-rendering",
 )}
diff --git a/components/style/properties/longhands/inherited_svg.mako.rs b/components/style/properties/longhands/inherited_svg.mako.rs
index 1d75df08bd8..1839f90d6e6 100644
--- a/components/style/properties/longhands/inherited_svg.mako.rs
+++ b/components/style/properties/longhands/inherited_svg.mako.rs
@@ -17,6 +17,7 @@ ${helpers.single_keyword(
     engines="gecko",
     animation_value_type="discrete",
     spec="https://www.w3.org/TR/css-inline-3/#propdef-dominant-baseline",
+    gecko_enum_prefix="StyleDominantBaseline",
 )}
 
 ${helpers.single_keyword(
@@ -118,6 +119,7 @@ ${helpers.single_keyword(
     engines="gecko",
     animation_value_type="discrete",
     spec="https://www.w3.org/TR/SVG11/painting.html#StrokeLinejoinProperty",
+    gecko_enum_prefix = "StyleStrokeLinejoin",
 )}
 
 ${helpers.predefined_type(
diff --git a/components/style/properties/longhands/inherited_table.mako.rs b/components/style/properties/longhands/inherited_table.mako.rs
index 06b42e802b6..488fe5d2659 100644
--- a/components/style/properties/longhands/inherited_table.mako.rs
+++ b/components/style/properties/longhands/inherited_table.mako.rs
@@ -20,7 +20,7 @@ ${helpers.single_keyword(
     "empty-cells",
     "show hide",
     engines="gecko servo-2013",
-    gecko_constant_prefix="NS_STYLE_TABLE_EMPTY_CELLS",
+    gecko_enum_prefix="StyleEmptyCells",
     animation_value_type="discrete",
     spec="https://drafts.csswg.org/css-tables/#propdef-empty-cells",
     servo_restyle_damage="rebuild_and_reflow",
diff --git a/components/style/properties/longhands/inherited_text.mako.rs b/components/style/properties/longhands/inherited_text.mako.rs
index 9784e2529e9..f01bedb177e 100644
--- a/components/style/properties/longhands/inherited_text.mako.rs
+++ b/components/style/properties/longhands/inherited_text.mako.rs
@@ -382,8 +382,8 @@ ${helpers.single_keyword(
 // text underline offset
 ${helpers.predefined_type(
     "text-underline-offset",
-    "TextDecorationLength",
-    "generics::text::GenericTextDecorationLength::Auto",
+    "LengthPercentageOrAuto",
+    "computed::LengthPercentageOrAuto::auto()",
     engines="gecko",
     animation_value_type="ComputedValue",
     gecko_pref="layout.css.text-underline-offset.enabled",
diff --git a/components/style/properties/longhands/position.mako.rs b/components/style/properties/longhands/position.mako.rs
index d974a0f5915..5e3cbf1324c 100644
--- a/components/style/properties/longhands/position.mako.rs
+++ b/components/style/properties/longhands/position.mako.rs
@@ -398,7 +398,7 @@ ${helpers.predefined_type(
     "computed::length::NonNegativeLengthPercentageOrNormal::normal()",
     engines="gecko servo-2013",
     alias="grid-column-gap" if engine == "gecko" else "",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     servo_2013_pref="layout.columns.enabled",
     spec="https://drafts.csswg.org/css-align-3/#propdef-column-gap",
     animation_value_type="NonNegativeLengthPercentageOrNormal",
diff --git a/components/style/properties/longhands/svg.mako.rs b/components/style/properties/longhands/svg.mako.rs
index f25cbb8e019..724c38b2d1b 100644
--- a/components/style/properties/longhands/svg.mako.rs
+++ b/components/style/properties/longhands/svg.mako.rs
@@ -69,6 +69,7 @@ ${helpers.single_keyword(
     "mask-type",
     "luminance alpha",
     engines="gecko",
+    gecko_enum_prefix="StyleMaskType",
     animation_value_type="discrete",
     spec="https://drafts.fxtf.org/css-masking/#propdef-mask-type",
 )}
diff --git a/components/style/properties/longhands/table.mako.rs b/components/style/properties/longhands/table.mako.rs
index 0564942fc0a..104c28b8e04 100644
--- a/components/style/properties/longhands/table.mako.rs
+++ b/components/style/properties/longhands/table.mako.rs
@@ -12,6 +12,7 @@ ${helpers.single_keyword(
     engines="gecko servo-2013",
     gecko_ffi_name="mLayoutStrategy",
     animation_value_type="discrete",
+    gecko_enum_prefix="StyleTableLayout",
     spec="https://drafts.csswg.org/css-tables/#propdef-table-layout",
     servo_restyle_damage="reflow",
 )}
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 30a03f79290..d3e61867518 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -28,6 +28,7 @@ use crate::context::QuirksMode;
 #[cfg(feature = "servo")] use crate::computed_values;
 use crate::logical_geometry::WritingMode;
 use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
+use crate::computed_value_flags::*;
 use crate::media_queries::Device;
 use crate::parser::ParserContext;
 use crate::properties::longhands::system_font::SystemFont;
@@ -45,7 +46,6 @@ use crate::values::computed::NonNegativeLength;
 use crate::values::serialize_atom_name;
 use crate::rule_tree::StrongRuleNode;
 use crate::Zero;
-use self::computed_value_flags::*;
 use crate::str::{CssString, CssStringBorrow, CssStringWriter};
 use std::cell::Cell;
 
@@ -58,8 +58,6 @@ pub use self::cascade::*;
     import os.path
 %>
 
-#[path="${repr(os.path.join(os.path.dirname(__file__), 'computed_value_flags.rs'))[1:-1]}"]
-pub mod computed_value_flags;
 #[path="${repr(os.path.join(os.path.dirname(__file__), 'declaration_block.rs'))[1:-1]}"]
 pub mod declaration_block;
 #[path="${repr(os.path.join(os.path.dirname(__file__), 'cascade.rs'))[1:-1]}"]
@@ -1584,7 +1582,7 @@ impl UnparsedValue {
         longhand_id: LonghandId,
         custom_properties: Option<<&Arc<crate::custom_properties::CustomPropertiesMap>>,
         quirks_mode: QuirksMode,
-        environment: &::custom_properties::CssEnvironment,
+        device: &Device,
     ) -> PropertyDeclaration {
         let invalid_at_computed_value_time = || {
             let keyword = if longhand_id.inherited() {
@@ -1602,7 +1600,7 @@ impl UnparsedValue {
             &self.css,
             self.first_token_type,
             custom_properties,
-            environment,
+            device,
         ) {
             Ok(css) => css,
             Err(..) => return invalid_at_computed_value_time(),
@@ -1803,8 +1801,11 @@ impl ToCss for PropertyId {
 }
 
 /// The counted unknown property list which is used for css use counters.
+///
+/// FIXME: This should be just #[repr(u8)], but can't be because of ABI issues,
+/// see https://bugs.llvm.org/show_bug.cgi?id=44228.
 #[derive(Clone, Copy, Debug, Eq, FromPrimitive, Hash, PartialEq)]
-#[repr(u8)]
+#[repr(u32)]
 pub enum CountedUnknownProperty {
     % for prop in data.counted_unknown_properties:
     /// ${prop.name}
@@ -2894,9 +2895,18 @@ pub struct ComputedValues {
     /// We maintain this distinction in servo to reduce the amount of special
     /// casing.
     inner: ComputedValuesInner,
+
+    /// The pseudo-element that we're using.
+    pseudo: Option<PseudoElement>,
 }
 
 impl ComputedValues {
+    /// Returns the pseudo-element that this style represents.
+    #[cfg(feature = "servo")]
+    pub fn pseudo(&self) -> Option<<&PseudoElement> {
+        self.pseudo.as_ref()
+    }
+
     /// Returns whether this style's display value is equal to contents.
     pub fn is_display_contents(&self) -> bool {
         self.get_box().clone_display().is_contents()
@@ -2999,7 +3009,7 @@ impl ComputedValues {
 impl ComputedValues {
     /// Create a new refcounted `ComputedValues`
     pub fn new(
-        _: Option<<&PseudoElement>,
+        pseudo: Option<<&PseudoElement>,
         custom_properties: Option<Arc<crate::custom_properties::CustomPropertiesMap>>,
         writing_mode: WritingMode,
         flags: ComputedValueFlags,
@@ -3019,7 +3029,8 @@ impl ComputedValues {
             % for style_struct in data.active_style_structs():
                 ${style_struct.ident},
             % endfor
-            }
+            },
+            pseudo: pseudo.cloned(),
         })
     }
 
@@ -3433,6 +3444,9 @@ pub struct StyleBuilder<'a> {
     /// `StyleAdjuster` did any work.
     modified_reset: bool,
 
+    /// Whether this is the style for the root element.
+    pub is_root_element: bool,
+
     /// The writing mode flags.
     ///
     /// TODO(emilio): Make private.
@@ -3459,6 +3473,7 @@ impl<'a> StyleBuilder<'a> {
         pseudo: Option<<&'a PseudoElement>,
         rules: Option<StrongRuleNode>,
         custom_properties: Option<Arc<crate::custom_properties::CustomPropertiesMap>>,
+        is_root_element: bool,
     ) -> Self {
         debug_assert_eq!(parent_style.is_some(), parent_style_ignoring_first_line.is_some());
         #[cfg(feature = "gecko")]
@@ -3480,6 +3495,7 @@ impl<'a> StyleBuilder<'a> {
             pseudo,
             rules,
             modified_reset: false,
+            is_root_element,
             custom_properties,
             writing_mode: inherited_style.writing_mode,
             flags: Cell::new(flags),
@@ -3518,6 +3534,7 @@ impl<'a> StyleBuilder<'a> {
             reset_style,
             pseudo: None,
             modified_reset: false,
+            is_root_element: false,
             rules: None,
             custom_properties: style_to_derive_from.custom_properties().cloned(),
             writing_mode: style_to_derive_from.writing_mode,
@@ -3645,6 +3662,7 @@ impl<'a> StyleBuilder<'a> {
             pseudo,
             /* rules = */ None,
             parent.and_then(|p| p.custom_properties().cloned()),
+            /* is_root_element = */ false,
         );
         ret.visited_style = visited_style;
         ret
@@ -3827,9 +3845,9 @@ pub use self::lazy_static_module::INITIAL_SERVO_VALUES;
 #[allow(missing_docs)]
 mod lazy_static_module {
     use crate::logical_geometry::WritingMode;
+    use crate::computed_value_flags::ComputedValueFlags;
     use servo_arc::Arc;
     use super::{ComputedValues, ComputedValuesInner, longhands, style_structs};
-    use super::computed_value_flags::ComputedValueFlags;
 
     lazy_static! {
         /// The initial values for all style structs as defined by the specification.
@@ -3859,7 +3877,8 @@ mod lazy_static_module {
                 rules: None,
                 visited_style: None,
                 flags: ComputedValueFlags::empty(),
-            }
+            },
+            pseudo: None,
         };
     }
 }
diff --git a/components/style/properties/shorthands/column.mako.rs b/components/style/properties/shorthands/column.mako.rs
index f9612fd6c0c..d5e385faa4c 100644
--- a/components/style/properties/shorthands/column.mako.rs
+++ b/components/style/properties/shorthands/column.mako.rs
@@ -9,7 +9,8 @@
                     sub_properties="column-width column-count"
                     servo_2013_pref="layout.columns.enabled",
                     derive_serialize="True"
-                    extra_prefixes="moz" spec="https://drafts.csswg.org/css-multicol/#propdef-columns">
+                    extra_prefixes="moz:layout.css.prefixes.columns"
+                    spec="https://drafts.csswg.org/css-multicol/#propdef-columns">
     use crate::properties::longhands::{column_count, column_width};
 
     pub fn parse_value<'i, 't>(
@@ -59,7 +60,7 @@
 <%helpers:shorthand
     name="column-rule"
     engines="gecko"
-    extra_prefixes="moz"
+    extra_prefixes="moz:layout.css.prefixes.columns"
     sub_properties="column-rule-width column-rule-style column-rule-color"
     derive_serialize="True"
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-rule"