Auto merge of #24641 - emilio:gecko-sync, r=emilio

style: Sync changes from mozilla-central.

See individual commits for details.

https://bugzilla.mozilla.org/show_bug.cgi?id=1593642

38 files changed, 265 insertions, 300 deletions

diff --git a/components/malloc_size_of/lib.rs b/components/malloc_size_of/lib.rs
index af7147d8edb..1d5cbeaff1e 100644
--- a/components/malloc_size_of/lib.rs
+++ b/components/malloc_size_of/lib.rs
@@ -837,6 +837,7 @@ malloc_size_of_is_0!(app_units::Au);
 
 malloc_size_of_is_0!(cssparser::RGBA, cssparser::TokenSerializationType);
 
+#[cfg(feature = "servo")]
 malloc_size_of_is_0!(csp::Destination);
 
 #[cfg(feature = "url")]
diff --git a/components/selectors/context.rs b/components/selectors/context.rs
index d159891ff02..44d586c8d84 100644
--- a/components/selectors/context.rs
+++ b/components/selectors/context.rs
@@ -189,15 +189,6 @@ where
         }
     }
 
-    /// Override the quirks mode we're matching against.
-    ///
-    /// FIXME(emilio): This is a hack for XBL quirks-mode mismatches.
-    #[inline]
-    pub fn set_quirks_mode(&mut self, quirks_mode: QuirksMode) {
-        self.quirks_mode = quirks_mode;
-        self.classes_and_ids_case_sensitivity = quirks_mode.classes_and_ids_case_sensitivity();
-    }
-
     /// Whether we're matching a nested selector.
     #[inline]
     pub fn is_nested(&self) -> bool {
diff --git a/components/selectors/matching.rs b/components/selectors/matching.rs
index 45acc13e7e1..49b7f3dbd32 100644
--- a/components/selectors/matching.rs
+++ b/components/selectors/matching.rs
@@ -667,7 +667,7 @@ where
 
     match *selector {
         Component::Combinator(_) => unreachable!(),
-        Component::Part(ref part) => element.is_part(part),
+        Component::Part(ref parts) => parts.iter().all(|part| element.is_part(part)),
         Component::Slotted(ref selector) => {
             // <slots> are never flattened tree slottables.
             !element.is_html_slot_element() &&
diff --git a/components/selectors/parser.rs b/components/selectors/parser.rs
index 982dff793a8..507121bbf97 100644
--- a/components/selectors/parser.rs
+++ b/components/selectors/parser.rs
@@ -607,7 +607,7 @@ impl<Impl: SelectorImpl> Selector<Impl> {
     }
 
     #[inline]
-    pub fn part(&self) -> Option<&Impl::PartName> {
+    pub fn parts(&self) -> Option<&[Impl::PartName]> {
         if !self.is_part() {
             return None;
         }
@@ -1013,7 +1013,7 @@ pub enum Component<Impl: SelectorImpl> {
     Slotted(Selector<Impl>),
     /// The `::part` pseudo-element.
     ///   https://drafts.csswg.org/css-shadow-parts/#part
-    Part(#[shmem(field_bound)] Impl::PartName),
+    Part(#[shmem(field_bound)] Box<[Impl::PartName]>),
     /// The `:host` pseudo-class:
     ///
     /// https://drafts.csswg.org/css-scoping/#host-selector
@@ -1302,9 +1302,14 @@ impl<Impl: SelectorImpl> ToCss for Component<Impl> {
                 selector.to_css(dest)?;
                 dest.write_char(')')
             },
-            Part(ref part_name) => {
+            Part(ref part_names) => {
                 dest.write_str("::part(")?;
-                display_to_css_identifier(part_name, dest)?;
+                for (i, name) in part_names.iter().enumerate() {
+                    if i != 0 {
+                        dest.write_char(' ')?;
+                    }
+                    display_to_css_identifier(name, dest)?;
+                }
                 dest.write_char(')')
             },
             PseudoElement(ref p) => p.to_css(dest),
@@ -1626,7 +1631,7 @@ enum SimpleSelectorParseResult<Impl: SelectorImpl> {
     SimpleSelector(Component<Impl>),
     PseudoElement(Impl::PseudoElement),
     SlottedPseudo(Selector<Impl>),
-    PartPseudo(Impl::PartName),
+    PartPseudo(Box<[Impl::PartName]>),
 }
 
 #[derive(Debug)]
@@ -2029,10 +2034,10 @@ where
             SimpleSelectorParseResult::SimpleSelector(s) => {
                 builder.push_simple_selector(s);
             },
-            SimpleSelectorParseResult::PartPseudo(part_name) => {
+            SimpleSelectorParseResult::PartPseudo(part_names) => {
                 state.insert(SelectorParsingState::AFTER_PART);
                 builder.push_combinator(Combinator::Part);
-                builder.push_simple_selector(Component::Part(part_name));
+                builder.push_simple_selector(Component::Part(part_names));
             },
             SimpleSelectorParseResult::SlottedPseudo(selector) => {
                 state.insert(SelectorParsingState::AFTER_SLOTTED);
@@ -2193,10 +2198,15 @@ where
                                 input.new_custom_error(SelectorParseErrorKind::InvalidState)
                             );
                         }
-                        let name = input.parse_nested_block(|input| {
-                            Ok(input.expect_ident()?.as_ref().into())
+                        let names = input.parse_nested_block(|input| {
+                            let mut result = Vec::with_capacity(1);
+                            result.push(input.expect_ident()?.as_ref().into());
+                            while !input.is_exhausted() {
+                                result.push(input.expect_ident()?.as_ref().into());
+                            }
+                            Ok(result.into_boxed_slice())
                         })?;
-                        return Ok(Some(SimpleSelectorParseResult::PartPseudo(name)));
+                        return Ok(Some(SimpleSelectorParseResult::PartPseudo(names)));
                     }
                     if P::parse_slotted(parser) && name.eq_ignore_ascii_case("slotted") {
                         if !state.allows_slotted() {
@@ -3051,8 +3061,7 @@ pub mod tests {
 
         assert!(parse("::part()").is_err());
         assert!(parse("::part(42)").is_err());
-        // Though note https://github.com/w3c/csswg-drafts/issues/3502
-        assert!(parse("::part(foo bar)").is_err());
+        assert!(parse("::part(foo bar)").is_ok());
         assert!(parse("::part(foo):hover").is_ok());
         assert!(parse("::part(foo) + bar").is_err());
 
diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
index 1a727387b7e..f15c64e2f56 100644
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@@ -25,7 +25,6 @@ servo-layout-2020 = []
 gecko_debug = []
 gecko_refcount_logging = []
 gecko_profiler = []
-moz_xbl = []
 
 [dependencies]
 app_units = "0.7"
diff --git a/components/style/build_gecko.rs b/components/style/build_gecko.rs
index 86d2098d063..a502b7d45f9 100644
--- a/components/style/build_gecko.rs
+++ b/components/style/build_gecko.rs
@@ -109,7 +109,10 @@ fn add_headers_recursively(path: PathBuf, added_paths: &mut HashSet<PathBuf>) {
 
 fn add_include(name: &str) -> String {
     let mut added_paths = ADDED_PATHS.lock().unwrap();
-    let file = search_include(name).expect("Include not found!");
+    let file = match search_include(name) {
+        Some(file) => file,
+        None => panic!("Include not found: {}", name),
+    };
     let result = String::from(file.to_str().unwrap());
     add_headers_recursively(file, &mut *added_paths);
     result
diff --git a/components/style/dom.rs b/components/style/dom.rs
index 7d56cc543e7..2ea64bbb3dc 100644
--- a/components/style/dom.rs
+++ b/components/style/dom.rs
@@ -776,14 +776,6 @@ pub trait TElement:
         return data.hint.has_animation_hint();
     }
 
-    /// Returns the anonymous content for the current element's XBL binding,
-    /// given if any.
-    ///
-    /// This is used in Gecko for XBL.
-    fn xbl_binding_anonymous_content(&self) -> Option<Self::ConcreteNode> {
-        None
-    }
-
     /// The shadow root this element is a host of.
     fn shadow_root(&self) -> Option<<Self::ConcreteNode as TNode>::ConcreteShadowRoot>;
 
diff --git a/components/style/gecko/media_features.rs b/components/style/gecko/media_features.rs
index ce084c9d16b..e3de8dbfaaa 100644
--- a/components/style/gecko/media_features.rs
+++ b/components/style/gecko/media_features.rs
@@ -598,8 +598,7 @@ lazy_static! {
             atom!("device-pixel-ratio"),
             AllowsRanges::Yes,
             Evaluator::Float(eval_device_pixel_ratio),
-            ParsingRequirements::WEBKIT_PREFIX |
-                ParsingRequirements::WEBKIT_DEVICE_PIXEL_RATIO_PREF_ENABLED,
+            ParsingRequirements::WEBKIT_PREFIX,
         ),
         // -webkit-transform-3d.
         feature!(
diff --git a/components/style/gecko/wrapper.rs b/components/style/gecko/wrapper.rs
index fd0ac9db8a6..c2c4a0c0feb 100644
--- a/components/style/gecko/wrapper.rs
+++ b/components/style/gecko/wrapper.rs
@@ -44,8 +44,6 @@ use crate::gecko_bindings::bindings::{Gecko_ElementState, Gecko_GetDocumentLWThe
 use crate::gecko_bindings::bindings::{Gecko_SetNodeFlags, Gecko_UnsetNodeFlags};
 use crate::gecko_bindings::structs;
 use crate::gecko_bindings::structs::nsChangeHint;
-#[cfg(feature = "moz_xbl")]
-use crate::gecko_bindings::structs::nsXBLBinding as RawGeckoXBLBinding;
 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;
@@ -86,8 +84,6 @@ use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::mem;
 use std::ptr;
-#[cfg(not(feature = "moz_xbl"))]
-use values::Impossible;
 
 #[inline]
 fn elements_with_id<'a, 'le>(
@@ -317,7 +313,7 @@ impl<'ln> GeckoNode<'ln> {
         }
 
         if let Some(parent) = parent_el {
-            if parent.shadow_root().is_some() || parent.xbl_binding().is_some() {
+            if parent.shadow_root().is_some() {
                 return false;
             }
         }
@@ -530,52 +526,6 @@ impl<'a> Iterator for GeckoChildrenIterator<'a> {
     }
 }
 
-/// A Simple wrapper over a non-null Gecko `nsXBLBinding` pointer.
-#[cfg(feature = "moz_xbl")]
-#[derive(Clone, Copy)]
-pub struct GeckoXBLBinding<'lb>(pub &'lb RawGeckoXBLBinding);
-
-#[cfg(feature = "moz_xbl")]
-impl<'lb> GeckoXBLBinding<'lb> {
-    #[inline]
-    fn base_binding(&self) -> Option<Self> {
-        unsafe { self.0.mNextBinding.mRawPtr.as_ref().map(GeckoXBLBinding) }
-    }
-
-    #[inline]
-    fn anon_content(&self) -> *const nsIContent {
-        self.0.mContent.raw::<nsIContent>()
-    }
-
-    // This duplicates the logic in Gecko's
-    // nsBindingManager::GetBindingWithContent.
-    fn binding_with_content(&self) -> Option<Self> {
-        let mut binding = *self;
-        loop {
-            if !binding.anon_content().is_null() {
-                return Some(binding);
-            }
-            binding = binding.base_binding()?;
-        }
-    }
-}
-
-/// A stub wraper for GeckoXBLBinding.
-#[cfg(not(feature = "moz_xbl"))]
-pub struct GeckoXBLBinding<'lb>(&'lb Impossible);
-
-#[cfg(not(feature = "moz_xbl"))]
-impl<'lb> GeckoXBLBinding<'lb> {
-    #[inline]
-    fn anon_content(&self) -> *const nsIContent {
-        match *self.0 {}
-    }
-
-    fn binding_with_content(&self) -> Option<Self> {
-        None
-    }
-}
-
 /// A simple wrapper over a non-null Gecko `Element` pointer.
 #[derive(Clone, Copy)]
 pub struct GeckoElement<'le>(pub &'le RawGeckoElement);
@@ -701,39 +651,6 @@ impl<'le> GeckoElement<'le> {
         })
     }
 
-    #[cfg(feature = "moz_xbl")]
-    #[inline]
-    fn may_be_in_binding_manager(&self) -> bool {
-        self.flags() & (structs::NODE_MAY_BE_IN_BINDING_MNGR as u32) != 0
-    }
-
-    #[cfg(feature = "moz_xbl")]
-    #[inline]
-    fn xbl_binding(&self) -> Option<GeckoXBLBinding<'le>> {
-        if !self.may_be_in_binding_manager() {
-            return None;
-        }
-
-        let slots = self.extended_slots()?;
-        unsafe { slots.mXBLBinding.mRawPtr.as_ref().map(GeckoXBLBinding) }
-    }
-
-    #[cfg(not(feature = "moz_xbl"))]
-    #[inline]
-    fn xbl_binding(&self) -> Option<GeckoXBLBinding<'le>> {
-        None
-    }
-
-    #[inline]
-    fn xbl_binding_with_content(&self) -> Option<GeckoXBLBinding<'le>> {
-        self.xbl_binding().and_then(|b| b.binding_with_content())
-    }
-
-    #[inline]
-    fn has_xbl_binding_with_content(&self) -> bool {
-        !self.xbl_binding_with_content().is_none()
-    }
-
     #[inline]
     fn namespace_id(&self) -> i32 {
         self.as_node().node_info().mInner.mNamespaceID
@@ -1107,9 +1024,8 @@ impl<'le> TElement for GeckoElement<'le> {
         // This condition is similar to the check that
         // StyleChildrenIterator::IsNeeded does, except that it might return
         // true if we used to (but no longer) have anonymous content from
-        // ::before/::after, XBL bindings, or nsIAnonymousContentCreators.
+        // ::before/::after, or nsIAnonymousContentCreators.
         if self.is_in_anonymous_subtree() ||
-            self.has_xbl_binding_with_content() ||
             self.is_html_slot_element() ||
             self.shadow_root().is_some() ||
             self.may_have_anonymous_children()
@@ -1595,11 +1511,6 @@ impl<'le> TElement for GeckoElement<'le> {
         self.may_have_animations() && unsafe { Gecko_ElementHasCSSTransitions(self.0) }
     }
 
-    fn xbl_binding_anonymous_content(&self) -> Option<GeckoNode<'le>> {
-        self.xbl_binding_with_content()
-            .map(|b| unsafe { GeckoNode::from_content(&*b.anon_content()) })
-    }
-
     fn might_need_transitions_update(
         &self,
         old_style: Option<&ComputedValues>,
diff --git a/components/style/invalidation/element/document_state.rs b/components/style/invalidation/element/document_state.rs
index 77b205f1b26..4e29e91eb0e 100644
--- a/components/style/invalidation/element/document_state.rs
+++ b/components/style/invalidation/element/document_state.rs
@@ -31,9 +31,6 @@ impl Default for InvalidationMatchingData {
 /// An invalidation processor for style changes due to state and attribute
 /// changes.
 pub struct DocumentStateInvalidationProcessor<'a, E: TElement, I> {
-    // TODO(emilio): We might want to just run everything for every possible
-    // binding along with the document data, or just apply the XBL stuff to the
-    // bound subtrees.
     rules: I,
     matching_context: MatchingContext<'a, E::Impl>,
     document_states_changed: DocumentState,
diff --git a/components/style/invalidation/element/invalidator.rs b/components/style/invalidation/element/invalidator.rs
index 2889c3e7b9d..3487d7b9353 100644
--- a/components/style/invalidation/element/invalidator.rs
+++ b/components/style/invalidation/element/invalidator.rs
@@ -28,7 +28,7 @@ where
 
     /// Whether the invalidation processor only cares about light-tree
     /// descendants of a given element, that is, doesn't invalidate
-    /// pseudo-elements, NAC, or XBL anon content.
+    /// pseudo-elements, NAC, shadow dom...
     fn light_tree_only(&self) -> bool {
         false
     }
@@ -455,11 +455,6 @@ where
 
         let mut sibling_invalidations = InvalidationVector::new();
         for child in parent.dom_children() {
-            // TODO(emilio): We handle <xbl:children> fine, because they appear
-            // in selector-matching (note bug 1374247, though).
-            //
-            // This probably needs a shadow root check on `child` here, and
-            // recursing if that's the case.
             let child = match child.as_element() {
                 Some(e) => e,
                 None => continue,
@@ -574,13 +569,6 @@ where
             any_descendant |= self.invalidate_dom_descendants_of(root.as_node(), invalidations);
         }
 
-        // This is needed for XBL (technically) unconditionally, because XBL
-        // bindings do not block combinators in any way. However this is kinda
-        // broken anyway, since we should be looking at XBL rules too.
-        if let Some(anon_content) = self.element.xbl_binding_anonymous_content() {
-            any_descendant |= self.invalidate_dom_descendants_of(anon_content, invalidations);
-        }
-
         if let Some(marker) = self.element.marker_pseudo_element() {
             any_descendant |= self.invalidate_pseudo_element_or_nac(marker, invalidations);
         }
diff --git a/components/style/lib.rs b/components/style/lib.rs
index 35070b0f254..354950f9c15 100644
--- a/components/style/lib.rs
+++ b/components/style/lib.rs
@@ -78,7 +78,6 @@ extern crate parking_lot;
 extern crate precomputed_hash;
 extern crate rayon;
 extern crate selectors;
-#[cfg(feature = "servo")]
 #[macro_use]
 extern crate serde;
 pub extern crate servo_arc;
diff --git a/components/style/media_queries/media_feature.rs b/components/style/media_queries/media_feature.rs
index c5251f7419f..a273e7f51be 100644
--- a/components/style/media_queries/media_feature.rs
+++ b/components/style/media_queries/media_feature.rs
@@ -123,9 +123,6 @@ bitflags! {
         const CHROME_AND_UA_ONLY = 1 << 0;
         /// The feature requires a -webkit- prefix.
         const WEBKIT_PREFIX = 1 << 1;
-        /// The feature requires the webkit-device-pixel-ratio preference to be
-        /// enabled.
-        const WEBKIT_DEVICE_PIXEL_RATIO_PREF_ENABLED = 1 << 2;
     }
 }
 
diff --git a/components/style/media_queries/media_feature_expression.rs b/components/style/media_queries/media_feature_expression.rs
index d4124450dc5..4704fab0ffc 100644
--- a/components/style/media_queries/media_feature_expression.rs
+++ b/components/style/media_queries/media_feature_expression.rs
@@ -242,6 +242,17 @@ fn consume_operation_or_colon(input: &mut Parser) -> Result<Option<Operator>, ()
     }))
 }
 
+#[allow(unused_variables)]
+fn disabled_by_pref(feature: &Atom) -> bool {
+    #[cfg(feature = "gecko")]
+    {
+        if *feature == atom!("-moz-touch-enabled") {
+            return !static_prefs::pref!("layout.css.moz-touch-enabled.enabled");
+        }
+    }
+    false
+}
+
 impl MediaFeatureExpression {
     fn new(
         feature_index: usize,
@@ -279,81 +290,53 @@ impl MediaFeatureExpression {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self, ParseError<'i>> {
-        // FIXME: remove extra indented block when lifetimes are non-lexical
-        let feature_index;
-        let feature;
-        let range;
-        {
-            let location = input.current_source_location();
-            let ident = input.expect_ident()?;
+        let mut requirements = ParsingRequirements::empty();
+        let location = input.current_source_location();
+        let ident = input.expect_ident()?;
 
-            let mut requirements = ParsingRequirements::empty();
-
-            if context.in_ua_or_chrome_sheet() {
-                requirements.insert(ParsingRequirements::CHROME_AND_UA_ONLY);
-            }
+        if context.in_ua_or_chrome_sheet() {
+            requirements.insert(ParsingRequirements::CHROME_AND_UA_ONLY);
+        }
 
-            let result = {
-                let mut feature_name = &**ident;
+        let mut feature_name = &**ident;
 
-                #[cfg(feature = "gecko")]
-                {
-                    if starts_with_ignore_ascii_case(feature_name, "-webkit-") {
-                        feature_name = &feature_name[8..];
-                        requirements.insert(ParsingRequirements::WEBKIT_PREFIX);
-                        if static_prefs::pref!("layout.css.prefixes.device-pixel-ratio-webkit") {
-                            requirements.insert(
-                                ParsingRequirements::WEBKIT_DEVICE_PIXEL_RATIO_PREF_ENABLED,
-                            );
-                        }
-                    }
-                }
+        if starts_with_ignore_ascii_case(feature_name, "-webkit-") {
+            feature_name = &feature_name[8..];
+            requirements.insert(ParsingRequirements::WEBKIT_PREFIX);
+        }
 
-                let range = if starts_with_ignore_ascii_case(feature_name, "min-") {
-                    feature_name = &feature_name[4..];
-                    Some(Range::Min)
-                } else if starts_with_ignore_ascii_case(feature_name, "max-") {
-                    feature_name = &feature_name[4..];
-                    Some(Range::Max)
-                } else {
-                    None
-                };
-
-                let atom = Atom::from(string_as_ascii_lowercase(feature_name));
-                match MEDIA_FEATURES
-                    .iter()
-                    .enumerate()
-                    .find(|(_, f)| f.name == atom)
-                {
-                    Some((i, f)) => Ok((i, f, range)),
-                    None => Err(()),
-                }
-            };
+        let range = if starts_with_ignore_ascii_case(feature_name, "min-") {
+            feature_name = &feature_name[4..];
+            Some(Range::Min)
+        } else if starts_with_ignore_ascii_case(feature_name, "max-") {
+            feature_name = &feature_name[4..];
+            Some(Range::Max)
+        } else {
+            None
+        };
 
-            match result {
-                Ok((i, f, r)) => {
-                    feature_index = i;
-                    feature = f;
-                    range = r;
-                },
-                Err(()) => {
-                    return Err(location.new_custom_error(
-                        StyleParseErrorKind::MediaQueryExpectedFeatureName(ident.clone()),
-                    ));
-                },
-            }
+        let atom = Atom::from(string_as_ascii_lowercase(feature_name));
 
-            if !(feature.requirements & !requirements).is_empty() {
+        let (feature_index, feature) = match MEDIA_FEATURES
+            .iter()
+            .enumerate()
+            .find(|(_, f)| f.name == atom)
+        {
+            Some((i, f)) => (i, f),
+            None => {
                 return Err(location.new_custom_error(
                     StyleParseErrorKind::MediaQueryExpectedFeatureName(ident.clone()),
-                ));
-            }
+                ))
+            },
+        };
 
-            if range.is_some() && !feature.allows_ranges() {
-                return Err(location.new_custom_error(
-                    StyleParseErrorKind::MediaQueryExpectedFeatureName(ident.clone()),
-                ));
-            }
+        if disabled_by_pref(&feature.name) ||
+            !requirements.contains(feature.requirements) ||
+            (range.is_some() && !feature.allows_ranges())
+        {
+            return Err(location.new_custom_error(
+                StyleParseErrorKind::MediaQueryExpectedFeatureName(ident.clone()),
+            ));
         }
 
         let operator = input.try(consume_operation_or_colon);
diff --git a/components/style/properties/counted_unknown_properties.py b/components/style/properties/counted_unknown_properties.py
index 826bbf740a3..de36199e77a 100644
--- a/components/style/properties/counted_unknown_properties.py
+++ b/components/style/properties/counted_unknown_properties.py
@@ -13,7 +13,6 @@
 #    "offset"
 COUNTED_UNKNOWN_PROPERTIES = [
     "-webkit-font-smoothing",
-    "zoom",
     "-webkit-tap-highlight-color",
     "speak",
     "text-size-adjust",
diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index 97321fcbd38..7783c7eebd3 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -276,11 +276,6 @@ impl ComputedValuesInner {
     pub fn get_raw_visited_style(&self) -> &Option<RawOffsetArc<ComputedValues>> {
         &self.visited_style
     }
-
-    #[allow(non_snake_case)]
-    pub fn has_moz_binding(&self) -> bool {
-        !self.get_box().gecko.mBinding.is_none()
-    }
 }
 
 <%def name="declare_style_struct(style_struct)">
diff --git a/components/style/properties/longhands/box.mako.rs b/components/style/properties/longhands/box.mako.rs
index 815dcab313e..a68b179c4c0 100644
--- a/components/style/properties/longhands/box.mako.rs
+++ b/components/style/properties/longhands/box.mako.rs
@@ -396,7 +396,7 @@ ${helpers.predefined_type(
     engines="gecko",
     animation_value_type="ComputedValue",
     gecko_pref="layout.css.motion-path.enabled",
-    flags="CREATES_STACKING_CONTEXT FIXPOS_CB",
+    flags="CREATES_STACKING_CONTEXT FIXPOS_CB CAN_ANIMATE_ON_COMPOSITOR",
     spec="https://drafts.fxtf.org/motion-1/#offset-path-property",
     servo_restyle_damage="reflow_out_of_flow"
 )}
@@ -409,6 +409,7 @@ ${helpers.predefined_type(
     engines="gecko",
     animation_value_type="ComputedValue",
     gecko_pref="layout.css.motion-path.enabled",
+    flags="CAN_ANIMATE_ON_COMPOSITOR",
     spec="https://drafts.fxtf.org/motion-1/#offset-distance-property",
     servo_restyle_damage="reflow_out_of_flow"
 )}
@@ -421,6 +422,7 @@ ${helpers.predefined_type(
     engines="gecko",
     animation_value_type="ComputedValue",
     gecko_pref="layout.css.motion-path.enabled",
+    flags="CAN_ANIMATE_ON_COMPOSITOR",
     spec="https://drafts.fxtf.org/motion-1/#offset-rotate-property",
     servo_restyle_damage="reflow_out_of_flow"
 )}
@@ -433,6 +435,7 @@ ${helpers.predefined_type(
     engines="gecko",
     animation_value_type="ComputedValue",
     gecko_pref="layout.css.motion-path.enabled",
+    flags="CAN_ANIMATE_ON_COMPOSITOR",
     spec="https://drafts.fxtf.org/motion-1/#offset-anchor-property",
     servo_restyle_damage="reflow_out_of_flow",
     boxed=True
@@ -453,7 +456,6 @@ ${helpers.predefined_type(
     "ScrollSnapAlign",
     "computed::ScrollSnapAlign::none()",
     engines="gecko",
-    gecko_pref="layout.css.scroll-snap-v1.enabled",
     spec="https://drafts.csswg.org/css-scroll-snap-1/#scroll-snap-align",
     animation_value_type="discrete",
 )}
@@ -631,18 +633,6 @@ ${helpers.predefined_type(
     gecko_ffi_name="mAppearance",
 )}
 
-${helpers.predefined_type(
-    "-moz-binding",
-    "url::UrlOrNone",
-    "computed::url::UrlOrNone::none()",
-    engines="gecko",
-    animation_value_type="none",
-    gecko_ffi_name="mBinding",
-    gecko_pref="layout.css.moz-binding.content.enabled",
-    enabled_in="chrome",
-    spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-binding)",
-)}
-
 ${helpers.single_keyword(
     "-moz-orient",
     "inline block horizontal vertical",
diff --git a/components/style/properties/longhands/margin.mako.rs b/components/style/properties/longhands/margin.mako.rs
index 4ad056f05b2..80c765faab7 100644
--- a/components/style/properties/longhands/margin.mako.rs
+++ b/components/style/properties/longhands/margin.mako.rs
@@ -34,7 +34,6 @@
         "Length",
         "computed::Length::zero()",
         engines="gecko",
-        gecko_pref="layout.css.scroll-snap-v1.enabled",
         logical=side[1],
         logical_group="scroll-margin",
         spec="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-margin-%s" % side[0],
diff --git a/components/style/properties/longhands/padding.mako.rs b/components/style/properties/longhands/padding.mako.rs
index 3089c0acb92..79668df7bbf 100644
--- a/components/style/properties/longhands/padding.mako.rs
+++ b/components/style/properties/longhands/padding.mako.rs
@@ -33,7 +33,6 @@
         "NonNegativeLengthPercentageOrAuto",
         "computed::NonNegativeLengthPercentageOrAuto::auto()",
         engines="gecko",
-        gecko_pref="layout.css.scroll-snap-v1.enabled",
         logical=side[1],
         logical_group="scroll-padding",
         spec="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-padding-%s" % side[0],
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 24dfe1c57b6..fe4d3cceaf8 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -1876,7 +1876,19 @@ impl PropertyId {
         if let Some(id) = static_id(property_name) {
             return Ok(match *id {
                 StaticId::Longhand(id) => PropertyId::Longhand(id),
-                StaticId::Shorthand(id) => PropertyId::Shorthand(id),
+                StaticId::Shorthand(id) => {
+                    #[cfg(feature = "gecko")]
+                    {
+                        // We want to count `zoom` even if disabled.
+                        if matches!(id, ShorthandId::Zoom) {
+                            if let Some(counters) = use_counters {
+                                counters.non_custom_properties.record(id.into());
+                            }
+                        }
+                    }
+
+                    PropertyId::Shorthand(id)
+                },
                 StaticId::LonghandAlias(id, alias) => PropertyId::LonghandAlias(id, alias),
                 StaticId::ShorthandAlias(id, alias) => PropertyId::ShorthandAlias(id, alias),
                 StaticId::CountedUnknown(unknown_prop) => {
@@ -3065,10 +3077,6 @@ impl ComputedValuesInner {
         self.rules.as_ref().unwrap()
     }
 
-    /// Whether this style has a -moz-binding value. This is always false for
-    /// Servo for obvious reasons.
-    pub fn has_moz_binding(&self) -> bool { false }
-
     #[inline]
     /// Returns whether the "content" property for the given style is completely
     /// ineffective, and would yield an empty `::before` or `::after`
diff --git a/components/style/properties/shorthands/box.mako.rs b/components/style/properties/shorthands/box.mako.rs
index 84d2cb220bd..7b4ce131922 100644
--- a/components/style/properties/shorthands/box.mako.rs
+++ b/components/style/properties/shorthands/box.mako.rs
@@ -441,3 +441,58 @@ ${helpers.two_properties_shorthand(
         }
     }
 </%helpers:shorthand>
+
+<%helpers:shorthand name="zoom" engines="gecko"
+                    sub_properties="transform transform-origin"
+                    gecko_pref="layout.css.zoom-transform-hack.enabled"
+                    flags="SHORTHAND_IN_GETCS IS_LEGACY_SHORTHAND"
+                    spec="Not a standard, only a compat hack">
+    use crate::parser::Parse;
+    use crate::values::specified::{Number, NumberOrPercentage, TransformOrigin};
+    use crate::values::generics::transform::{Transform, TransformOperation};
+
+    pub fn parse_value<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        let zoom = match input.try(|input| NumberOrPercentage::parse(context, input)) {
+            Ok(number_or_percent) => number_or_percent.to_number(),
+            Err(..) => {
+                input.expect_ident_matching("normal")?;
+                Number::new(1.0)
+            },
+        };
+
+        // Make sure that the initial value matches the values for the
+        // longhands, just for general sanity.
+        //
+        // FIXME: Should we just do this for the "normal" case? Seems weird
+        // either way, so maybe not?
+        Ok(if zoom.get() == 1.0 {
+            expanded! {
+                transform: Transform::none(),
+                transform_origin: TransformOrigin::initial_value(),
+            }
+        } else {
+            expanded! {
+                transform: Transform(vec![TransformOperation::Scale(zoom, zoom)].into()),
+                transform_origin: TransformOrigin::zero_zero(),
+            }
+        })
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a>  {
+        fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
+            if self.transform.0.is_empty() && *self.transform_origin == TransformOrigin::initial_value() {
+                return 1.0f32.to_css(dest);
+            }
+            if *self.transform_origin != TransformOrigin::zero_zero() {
+                return Ok(())
+            }
+            match &*self.transform.0 {
+                [TransformOperation::Scale(x, y)] if x == y => x.to_css(dest),
+                _ => Ok(()),
+            }
+        }
+    }
+</%helpers:shorthand>
diff --git a/components/style/properties/shorthands/margin.mako.rs b/components/style/properties/shorthands/margin.mako.rs
index 5d5f2101563..128fc5fb303 100644
--- a/components/style/properties/shorthands/margin.mako.rs
+++ b/components/style/properties/shorthands/margin.mako.rs
@@ -38,7 +38,6 @@ ${helpers.four_sides_shorthand(
     "specified::Length::parse",
     engines="gecko",
     spec="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-margin",
-    gecko_pref="layout.css.scroll-snap-v1.enabled",
 )}
 
 ${helpers.two_properties_shorthand(
@@ -48,7 +47,6 @@ ${helpers.two_properties_shorthand(
     "specified::Length::parse",
     engines="gecko",
     spec="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-margin-block",
-    gecko_pref="layout.css.scroll-snap-v1.enabled",
 )}
 
 ${helpers.two_properties_shorthand(
@@ -58,5 +56,4 @@ ${helpers.two_properties_shorthand(
     "specified::Length::parse",
     engines="gecko",
     spec="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-margin-inline",
-    gecko_pref="layout.css.scroll-snap-v1.enabled",
 )}
diff --git a/components/style/properties/shorthands/padding.mako.rs b/components/style/properties/shorthands/padding.mako.rs
index 02db51a88d6..4d2ea361e15 100644
--- a/components/style/properties/shorthands/padding.mako.rs
+++ b/components/style/properties/shorthands/padding.mako.rs
@@ -36,7 +36,6 @@ ${helpers.four_sides_shorthand(
     "scroll-padding-%s",
     "specified::NonNegativeLengthPercentageOrAuto::parse",
     engines="gecko",
-    gecko_pref="layout.css.scroll-snap-v1.enabled",
     spec="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-padding"
 )}
 
@@ -46,7 +45,6 @@ ${helpers.two_properties_shorthand(
     "scroll-padding-block-end",
     "specified::NonNegativeLengthPercentageOrAuto::parse",
     engines="gecko",
-    gecko_pref="layout.css.scroll-snap-v1.enabled",
     spec="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-padding-block"
 )}
 
@@ -56,7 +54,6 @@ ${helpers.two_properties_shorthand(
     "scroll-padding-inline-end",
     "specified::NonNegativeLengthPercentageOrAuto::parse",
     engines="gecko",
-    gecko_pref="layout.css.scroll-snap-v1.enabled",
     spec="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-padding-inline"
 )}
 
diff --git a/components/style/stylist.rs b/components/style/stylist.rs
index ed9af91af14..ab6fe309f3f 100644
--- a/components/style/stylist.rs
+++ b/components/style/stylist.rs
@@ -2032,11 +2032,17 @@ impl CascadeData {
                         // Part is special, since given it doesn't have any
                         // selectors inside, it's not worth using a whole
                         // SelectorMap for it.
-                        if let Some(part) = selector.part() {
+                        if let Some(parts) = selector.parts() {
+                            // ::part() has all semantics, so we just need to
+                            // put any of them in the selector map.
+                            //
+                            // We choose the last one quite arbitrarily,
+                            // expecting it's slightly more likely to be more
+                            // specific.
                             self.part_rules
                                 .get_or_insert_with(|| Box::new(Default::default()))
                                 .for_insertion(pseudo_element)
-                                .try_entry(part.clone())?
+                                .try_entry(parts.last().unwrap().clone())?
                                 .or_insert_with(SmallVec::new)
                                 .try_push(rule)?;
                         } else {
diff --git a/components/style/traversal.rs b/components/style/traversal.rs
index 1f64e7f22f0..360f5b6a25c 100644
--- a/components/style/traversal.rs
+++ b/components/style/traversal.rs
@@ -267,7 +267,6 @@ pub trait DomTraversal<E: TElement>: Sync {
         context: &mut StyleContext<E>,
         parent: E,
         parent_data: &ElementData,
-        is_initial_style: bool,
     ) -> bool {
         debug_assert!(
             parent.has_current_styles_for_traversal(parent_data, context.shared.traversal_flags)
@@ -279,21 +278,6 @@ pub trait DomTraversal<E: TElement>: Sync {
             return true;
         }
 
-        // Gecko-only XBL handling.
-        //
-        // When we apply the XBL binding during frame construction, we restyle
-        // the whole subtree again if the binding is valid, so assuming it's
-        // likely to load valid bindings, we avoid wasted work here, which may
-        // be a very big perf hit when elements with bindings are nested
-        // heavily.
-        if cfg!(feature = "gecko") &&
-            is_initial_style &&
-            parent_data.styles.primary().has_moz_binding()
-        {
-            debug!("Parent {:?} has XBL binding, deferring traversal", parent);
-            return true;
-        }
-
         return false;
     }
 
@@ -520,8 +504,8 @@ pub fn recalc_style_at<E, D, F>(
         !child_cascade_requirement.can_skip_cascade() ||
         is_servo_nonincremental_layout();
 
-    traverse_children = traverse_children &&
-        !traversal.should_cull_subtree(context, element, &data, is_initial_style);
+    traverse_children =
+        traverse_children && !traversal.should_cull_subtree(context, element, &data);
 
     // Examine our children, and enqueue the appropriate ones for traversal.
     if traverse_children {
diff --git a/components/style/values/computed/angle.rs b/components/style/values/computed/angle.rs
index d8cdefb5263..ea321d22337 100644
--- a/components/style/values/computed/angle.rs
+++ b/components/style/values/computed/angle.rs
@@ -13,16 +13,17 @@ use std::{f32, f64};
 use style_traits::{CssWriter, ToCss};
 
 /// A computed angle in degrees.
-#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 #[derive(
     Add,
     Animate,
     Clone,
     Copy,
     Debug,
+    Deserialize,
     MallocSizeOf,
     PartialEq,
     PartialOrd,
+    Serialize,
     ToAnimatedZero,
     ToResolvedValue,
 )]
diff --git a/components/style/values/computed/length.rs b/components/style/values/computed/length.rs
index 6d61198d364..53cf7cbd696 100644
--- a/components/style/values/computed/length.rs
+++ b/components/style/values/computed/length.rs
@@ -75,7 +75,9 @@ impl ToComputedValue for specified::Length {
 ///
 /// https://drafts.csswg.org/css-values-4/#typedef-length-percentage
 #[allow(missing_docs)]
-#[derive(Clone, Copy, Debug, MallocSizeOf, ToAnimatedZero, ToResolvedValue)]
+#[derive(
+    Clone, Copy, Debug, Deserialize, MallocSizeOf, Serialize, ToAnimatedZero, ToResolvedValue,
+)]
 #[repr(C)]
 pub struct LengthPercentage {
     length: Length,
@@ -605,15 +607,16 @@ impl Size {
 }
 
 /// The computed `<length>` value.
-#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 #[derive(
     Animate,
     Clone,
     ComputeSquaredDistance,
     Copy,
+    Deserialize,
     MallocSizeOf,
     PartialEq,
     PartialOrd,
+    Serialize,
     ToAnimatedValue,
     ToAnimatedZero,
     ToResolvedValue,
diff --git a/components/style/values/computed/percentage.rs b/components/style/values/computed/percentage.rs
index c22f8ed5683..b5a734367b2 100644
--- a/components/style/values/computed/percentage.rs
+++ b/components/style/values/computed/percentage.rs
@@ -12,7 +12,6 @@ use std::fmt;
 use style_traits::{CssWriter, ToCss};
 
 /// A computed percentage.
-#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 #[derive(
     Animate,
     Clone,
@@ -20,9 +19,11 @@ use style_traits::{CssWriter, ToCss};
     Copy,
     Debug,
     Default,
+    Deserialize,
     MallocSizeOf,
     PartialEq,
     PartialOrd,
+    Serialize,
     SpecifiedValueInfo,
     ToAnimatedValue,
     ToAnimatedZero,
diff --git a/components/style/values/generics/motion.rs b/components/style/values/generics/motion.rs
index e9ccc045186..685eaad43e2 100644
--- a/components/style/values/generics/motion.rs
+++ b/components/style/values/generics/motion.rs
@@ -14,9 +14,11 @@ use crate::values::specified::SVGPathData;
     Clone,
     Copy,
     Debug,
+    Deserialize,
     MallocSizeOf,
     Parse,
     PartialEq,
+    Serialize,
     SpecifiedValueInfo,
     ToAnimatedZero,
     ToComputedValue,
@@ -41,8 +43,10 @@ pub enum RaySize {
     Clone,
     ComputeSquaredDistance,
     Debug,
+    Deserialize,
     MallocSizeOf,
     PartialEq,
+    Serialize,
     SpecifiedValueInfo,
     ToAnimatedZero,
     ToComputedValue,
diff --git a/components/style/values/specified/color.rs b/components/style/values/specified/color.rs
index acad3383014..01e5890d015 100644
--- a/components/style/values/specified/color.rs
+++ b/components/style/values/specified/color.rs
@@ -119,6 +119,10 @@ pub enum SystemColor {
     Buttonshadow,
     Buttontext,
     Captiontext,
+    #[parse(aliases = "-moz-field")]
+    Field,
+    #[parse(aliases = "-moz-fieldtext")]
+    Fieldtext,
     Graytext,
     Highlight,
     Highlighttext,
@@ -139,8 +143,6 @@ pub enum SystemColor {
     Windowframe,
     Windowtext,
     MozButtondefault,
-    MozField,
-    MozFieldtext,
     MozDialog,
     MozDialogtext,
     /// Used to highlight valid regions to drop something onto.
diff --git a/components/style/values/specified/image.rs b/components/style/values/specified/image.rs
index c7a6ac1870c..7488e631e54 100644
--- a/components/style/values/specified/image.rs
+++ b/components/style/values/specified/image.rs
@@ -435,10 +435,7 @@ impl Gradient {
                     let (color, mut p) = i.parse_nested_block(|i| {
                         let p = match_ignore_ascii_case! { &function,
                             "color-stop" => {
-                                let p = match NumberOrPercentage::parse(context, i)? {
-                                    NumberOrPercentage::Number(number) => Percentage::new(number.value),
-                                    NumberOrPercentage::Percentage(p) => p,
-                                };
+                                let p = NumberOrPercentage::parse(context, i)?.to_percentage();
                                 i.expect_comma()?;
                                 p
                             },
diff --git a/components/style/values/specified/mod.rs b/components/style/values/specified/mod.rs
index 160295c8f55..d10a399dd01 100644
--- a/components/style/values/specified/mod.rs
+++ b/components/style/values/specified/mod.rs
@@ -179,13 +179,26 @@ impl Parse for Number {
 
 impl Number {
     /// Returns a new number with the value `val`.
-    pub fn new(val: CSSFloat) -> Self {
-        Number {
-            value: val,
-            calc_clamping_mode: None,
+    fn new_with_clamping_mode(
+        value: CSSFloat,
+        calc_clamping_mode: Option<AllowedNumericType>,
+    ) -> Self {
+        Self {
+            value,
+            calc_clamping_mode,
         }
     }
 
+    /// Returns this percentage as a number.
+    pub fn to_percentage(&self) -> Percentage {
+        Percentage::new_with_clamping_mode(self.value, self.calc_clamping_mode)
+    }
+
+    /// Returns a new number with the value `val`.
+    pub fn new(val: CSSFloat) -> Self {
+        Self::new_with_clamping_mode(val, None)
+    }
+
     /// Returns whether this number came from a `calc()` expression.
     #[inline]
     pub fn was_calc(&self) -> bool {
@@ -370,6 +383,22 @@ impl NumberOrPercentage {
     ) -> Result<Self, ParseError<'i>> {
         Self::parse_with_clamping_mode(context, input, AllowedNumericType::NonNegative)
     }
+
+    /// Convert the number or the percentage to a number.
+    pub fn to_percentage(self) -> Percentage {
+        match self {
+            Self::Percentage(p) => p,
+            Self::Number(n) => n.to_percentage(),
+        }
+    }
+
+    /// Convert the number or the percentage to a number.
+    pub fn to_number(self) -> Number {
+        match self {
+            Self::Percentage(p) => p.to_number(),
+            Self::Number(n) => n,
+        }
+    }
 }
 
 impl Parse for NumberOrPercentage {
@@ -419,17 +448,7 @@ impl Parse for Opacity {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self, ParseError<'i>> {
-        let number = match NumberOrPercentage::parse(context, input)? {
-            NumberOrPercentage::Percentage(p) => Number {
-                value: p.get(),
-                calc_clamping_mode: if p.is_calc() {
-                    Some(AllowedNumericType::All)
-                } else {
-                    None
-                },
-            },
-            NumberOrPercentage::Number(n) => n,
-        };
+        let number = NumberOrPercentage::parse(context, input)?.to_number();
         Ok(Opacity(number))
     }
 }
diff --git a/components/style/values/specified/percentage.rs b/components/style/values/specified/percentage.rs
index acfa6db64af..64cb02bb424 100644
--- a/components/style/values/specified/percentage.rs
+++ b/components/style/values/specified/percentage.rs
@@ -8,6 +8,7 @@ use crate::parser::{Parse, ParserContext};
 use crate::values::computed::percentage::Percentage as ComputedPercentage;
 use crate::values::computed::{Context, ToComputedValue};
 use crate::values::specified::calc::CalcNode;
+use crate::values::specified::Number;
 use crate::values::{serialize_percentage, CSSFloat};
 use cssparser::{Parser, Token};
 use std::fmt::{self, Write};
@@ -46,13 +47,21 @@ impl ToCss for Percentage {
 
 impl Percentage {
     /// Creates a percentage from a numeric value.
-    pub fn new(value: CSSFloat) -> Self {
+    pub(super) fn new_with_clamping_mode(
+        value: CSSFloat,
+        calc_clamping_mode: Option<AllowedNumericType>,
+    ) -> Self {
         Self {
             value,
-            calc_clamping_mode: None,
+            calc_clamping_mode,
         }
     }
 
+    /// Creates a percentage from a numeric value.
+    pub fn new(value: CSSFloat) -> Self {
+        Self::new_with_clamping_mode(value, None)
+    }
+
     /// `0%`
     #[inline]
     pub fn zero() -> Self {
@@ -70,12 +79,18 @@ impl Percentage {
             calc_clamping_mode: None,
         }
     }
+
     /// Gets the underlying value for this float.
     pub fn get(&self) -> CSSFloat {
         self.calc_clamping_mode
             .map_or(self.value, |mode| mode.clamp(self.value))
     }
 
+    /// Returns this percentage as a number.
+    pub fn to_number(&self) -> Number {
+        Number::new_with_clamping_mode(self.value, self.calc_clamping_mode)
+    }
+
     /// Returns whether this percentage is a `calc()` value.
     pub fn is_calc(&self) -> bool {
         self.calc_clamping_mode.is_some()
diff --git a/components/style/values/specified/svg_path.rs b/components/style/values/specified/svg_path.rs
index 4f49029b51e..9a94af6a82f 100644
--- a/components/style/values/specified/svg_path.rs
+++ b/components/style/values/specified/svg_path.rs
@@ -46,7 +46,7 @@ impl SVGPathData {
 
     /// Create a normalized copy of this path by converting each relative
     /// command to an absolute command.
-    fn normalize(&self) -> Box<[PathCommand]> {
+    pub fn normalize(&self) -> Self {
         let mut state = PathTraversalState {
             subpath_start: CoordPair::new(0.0, 0.0),
             pos: CoordPair::new(0.0, 0.0),
@@ -56,7 +56,8 @@ impl SVGPathData {
             .iter()
             .map(|seg| seg.normalize(&mut state))
             .collect::<Vec<_>>();
-        result.into_boxed_slice()
+
+        SVGPathData(crate::ArcSlice::from_iter(result.into_iter()))
     }
 }
 
@@ -119,8 +120,9 @@ impl Animate for SVGPathData {
         // re-normalize again.
         let result = self
             .normalize()
+            .0
             .iter()
-            .zip(other.normalize().iter())
+            .zip(other.normalize().0.iter())
             .map(|(a, b)| a.animate(&b, procedure))
             .collect::<Result<Vec<_>, _>>()?;
 
@@ -134,8 +136,9 @@ impl ComputeSquaredDistance for SVGPathData {
             return Err(());
         }
         self.normalize()
+            .0
             .iter()
-            .zip(other.normalize().iter())
+            .zip(other.normalize().0.iter())
             .map(|(this, other)| this.compute_squared_distance(&other))
             .sum()
     }
diff --git a/components/style/values/specified/transform.rs b/components/style/values/specified/transform.rs
index 9d33fd4188f..157c6504856 100644
--- a/components/style/values/specified/transform.rs
+++ b/components/style/values/specified/transform.rs
@@ -33,6 +33,27 @@ pub type TransformOrigin = generic::TransformOrigin<
     Length,
 >;
 
+impl TransformOrigin {
+    /// Returns the initial specified value for `transform-origin`.
+    #[inline]
+    pub fn initial_value() -> Self {
+        Self::new(
+            OriginComponent::Length(LengthPercentage::Percentage(ComputedPercentage(0.5))),
+            OriginComponent::Length(LengthPercentage::Percentage(ComputedPercentage(0.5))),
+            Length::zero(),
+        )
+    }
+
+    /// Returns the `0 0` value.
+    pub fn zero_zero() -> Self {
+        Self::new(
+            OriginComponent::Length(LengthPercentage::zero()),
+            OriginComponent::Length(LengthPercentage::zero()),
+            Length::zero(),
+        )
+    }
+}
+
 impl Transform {
     /// Internal parse function for deciding if we wish to accept prefixed values or not
     ///
@@ -260,7 +281,7 @@ impl Parse for TransformOrigin {
         let parse_depth = |input: &mut Parser| {
             input
                 .try(|i| Length::parse(context, i))
-                .unwrap_or(Length::from_px(0.))
+                .unwrap_or(Length::zero())
         };
         match input.try(|i| OriginComponent::parse(context, i)) {
             Ok(x_origin @ OriginComponent::Center) => {
diff --git a/components/style_traits/Cargo.toml b/components/style_traits/Cargo.toml
index 213c09b08df..f3dd0df744f 100644
--- a/components/style_traits/Cargo.toml
+++ b/components/style_traits/Cargo.toml
@@ -10,7 +10,7 @@ name = "style_traits"
 path = "lib.rs"
 
 [features]
-servo = ["serde", "servo_atoms", "cssparser/serde", "webrender_api", "servo_url", "euclid/serde"]
+servo = ["servo_atoms", "cssparser/serde", "webrender_api", "servo_url", "euclid/serde"]
 gecko = []
 
 [dependencies]
@@ -22,7 +22,7 @@ lazy_static = "1"
 malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = "0.1"
 selectors = { path = "../selectors" }
-serde = {version = "1.0", optional = true}
+serde = "1.0"
 webrender_api = {git = "https://github.com/servo/webrender", optional = true}
 servo_atoms = {path = "../atoms", optional = true}
 servo_arc = { path = "../servo_arc" }
diff --git a/components/style_traits/lib.rs b/components/style_traits/lib.rs
index b2dcc8431cb..3fb17743c13 100644
--- a/components/style_traits/lib.rs
+++ b/components/style_traits/lib.rs
@@ -22,7 +22,6 @@ extern crate malloc_size_of;
 #[macro_use]
 extern crate malloc_size_of_derive;
 extern crate selectors;
-#[cfg(feature = "servo")]
 #[macro_use]
 extern crate serde;
 extern crate servo_arc;
diff --git a/components/style_traits/values.rs b/components/style_traits/values.rs
index 0c3166858a2..66c1d79cd07 100644
--- a/components/style_traits/values.rs
+++ b/components/style_traits/values.rs
@@ -507,7 +507,9 @@ pub mod specified {
 
     /// Whether to allow negative lengths or not.
     #[repr(u8)]
-    #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, PartialOrd, ToShmem)]
+    #[derive(
+        Clone, Copy, Debug, Deserialize, Eq, MallocSizeOf, PartialEq, PartialOrd, Serialize, ToShmem,
+    )]
     pub enum AllowedNumericType {
         /// Allow all kind of numeric values.
         All,