Replace all uses of the heapsize crate with malloc_size_of.

Servo currently uses `heapsize`, but Stylo/Gecko use `malloc_size_of`. `malloc_size_of` is better -- it handles various cases that `heapsize` does not -- so this patch changes Servo to use `malloc_size_of`. This patch makes the following changes to the `malloc_size_of` crate. - Adds `MallocSizeOf` trait implementations for numerous types, some built-in (e.g. `VecDeque`), some external and Servo-only (e.g. `string_cache`). - Makes `enclosing_size_of_op` optional, because vanilla jemalloc doesn't support that operation. - For `HashSet`/`HashMap`, falls back to a computed estimate when `enclosing_size_of_op` isn't available. - Adds an extern "C" `malloc_size_of` function that does the actual heap measurement; this is based on the same functions from the `heapsize` crate. This patch makes the following changes elsewhere. - Converts all the uses of `heapsize` to instead use `malloc_size_of`. - Disables the "heapsize"/"heap_size" feature for the external crates that provide it. - Removes the `HeapSizeOf` implementation from `hashglobe`. - Adds `ignore` annotations to a few `Rc`/`Arc`, because `malloc_size_of` doesn't derive those types, unlike `heapsize`.
2025-08-09 15:35:34 +01:00 · 2017-10-18 10:42:01 +11:00 · 2017-10-18 10:42:01 +11:00 · 4506f0d30c
commit 4506f0d30c
parent 421baa854e
269 changed files with 1418 additions and 1521 deletions
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@ -16,12 +16,11 @@ path = "lib.rs"
 doctest = false

 [features]
-gecko = ["malloc_size_of", "malloc_size_of_derive", "nsstring_vendor", "num_cpus",
+gecko = ["nsstring_vendor", "num_cpus",
         "style_traits/gecko", "fallible/known_system_malloc"]
 use_bindgen = ["bindgen", "regex", "toml"]
-servo = ["serde", "heapsize", "heapsize_derive",
-         "style_traits/servo", "servo_atoms", "servo_config", "html5ever",
-         "cssparser/heapsize", "cssparser/serde", "encoding", "smallvec/heapsizeof",
+servo = ["serde", "style_traits/servo", "servo_atoms", "servo_config", "html5ever",
+         "cssparser/serde", "encoding", "malloc_size_of/servo",

         # FIXME: Uncomment when https://github.com/servo/servo/pull/16953 has landed:
         #"arrayvec/use_union"
@ -42,16 +41,14 @@ euclid = "0.15"
 fallible = { path = "../fallible" }
 fnv = "1.0"
 hashglobe = { path = "../hashglobe" }
-heapsize = {version = "0.4", optional = true}
-heapsize_derive = {version = "0.1", optional = true}
 itertools = "0.5"
 itoa = "0.3"
 html5ever = {version = "0.20", optional = true}
 lazy_static = "0.2"
 lru_cache = { path = "../lru_cache" }
 log = "0.3"
-malloc_size_of = { path = "../malloc_size_of", optional=true }
-malloc_size_of_derive = { path = "../malloc_size_of_derive", optional=true }
+malloc_size_of = { path = "../malloc_size_of" }
+malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 matches = "0.1"
 nsstring_vendor = {path = "gecko_bindings/nsstring_vendor", optional = true}
 num_cpus = {version = "1.1.0", optional = true}
--- a/components/style/applicable_declarations.rs
+++ b/components/style/applicable_declarations.rs
@ -36,9 +36,7 @@ const SOURCE_ORDER_MASK: u32 = (1 << SOURCE_ORDER_BITS) - 1;
 const SOURCE_ORDER_MAX: u32 = SOURCE_ORDER_MASK;

 /// Stores the source order of a block and the cascade level it belongs to.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Eq, PartialEq)]
+#[derive(Clone, Copy, Eq, MallocSizeOf, PartialEq)]
 struct SourceOrderAndCascadeLevel(u32);

 impl SourceOrderAndCascadeLevel {
@ -76,13 +74,10 @@ impl Debug for SourceOrderAndCascadeLevel {
 ///
 /// This represents the declarations in a given declaration block for a given
 /// importance.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 pub struct ApplicableDeclarationBlock {
    /// The style source, either a style rule, or a property declaration block.
-    #[cfg_attr(feature = "gecko", ignore_malloc_size_of = "contains Arcs")]
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+    #[ignore_malloc_size_of = "Arc"]
    pub source: StyleSource,
    /// The source order of the block, and the cascade level it belongs to.
    order_and_level: SourceOrderAndCascadeLevel,
--- a/components/style/attr.rs
+++ b/components/style/attr.rs
@ -27,7 +27,7 @@ use values::specified::Length;
 const UNSIGNED_LONG_MAX: u32 = 2147483647;

 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum LengthOrPercentageOrAuto {
    Auto,
    Percentage(f32),
@ -35,7 +35,7 @@ pub enum LengthOrPercentageOrAuto {
 }

 #[derive(Clone, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum AttrValue {
    String(String),
    TokenList(String, Vec<Atom>),
@ -66,7 +66,7 @@ pub enum AttrValue {
    /// declaration block), but that avoids keeping a refcounted
    /// declarationblock for longer than needed.
    Declaration(String,
-                #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+                #[ignore_malloc_size_of = "Arc"]
                Arc<Locked<PropertyDeclarationBlock>>)
 }

@ -596,7 +596,7 @@ pub fn parse_length(mut value: &str) -> LengthOrPercentageOrAuto {

 /// A struct that uniquely identifies an element's attribute.
 #[derive(Clone, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct AttrIdentifier {
    pub local_name: LocalName,
    pub name: LocalName,
--- a/components/style/custom_properties.rs
+++ b/components/style/custom_properties.rs
@ -41,9 +41,7 @@ pub fn parse_name(s: &str) -> Result<&str, ()> {
 ///
 /// We preserve the original CSS for serialization, and also the variable
 /// references to other custom property names.
-#[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 pub struct VariableValue {
    css: String,

--- a/components/style/dom.rs
+++ b/components/style/dom.rs
@ -44,7 +44,7 @@ use traversal_flags::{TraversalFlags, self};
 /// data structures. Also, layout code tends to be faster when the DOM is not being accessed, for
 /// locality reasons. Using `OpaqueNode` enforces this invariant.
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf, Deserialize, Serialize))]
 pub struct OpaqueNode(pub usize);

 impl OpaqueNode {
--- a/components/style/element_state.rs
+++ b/components/style/element_state.rs
@ -14,8 +14,7 @@ bitflags! {
    ///
    /// TODO(emilio): We really really want to use the NS_EVENT_STATE bindings
    /// for this.
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(MallocSizeOf)]
    pub flags ElementState: u64 {
        /// The mouse is down on this element.
        /// <https://html.spec.whatwg.org/multipage/#selector-active>
--- a/components/style/invalidation/element/invalidation_map.rs
+++ b/components/style/invalidation/element/invalidation_map.rs
@ -55,14 +55,12 @@ pub fn dir_selector_to_state(s: &[u16]) -> ElementState {
 /// This allows us to quickly scan through the dependency sites of all style
 /// rules and determine the maximum effect that a given state or attribute
 /// change may have on the style of elements in the document.
-#[derive(Clone, Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub struct Dependency {
    /// The dependency selector.
    #[cfg_attr(feature = "gecko",
               ignore_malloc_size_of = "CssRules have primary refs, we measure there")]
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+    #[cfg_attr(feature = "servo", ignore_malloc_size_of = "Arc")]
    pub selector: Selector<SelectorImpl>,

    /// The offset into the selector that we should match on.
@ -115,9 +113,7 @@ impl SelectorMapEntry for Dependency {

 /// The same, but for state selectors, which can track more exactly what state
 /// do they track.
-#[derive(Clone, Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub struct StateDependency {
    /// The other dependency fields.
    pub dep: Dependency,
@ -139,9 +135,7 @@ impl SelectorMapEntry for StateDependency {
 /// In particular, we want to lookup as few things as possible to get the fewer
 /// selectors the better, so this looks up by id, class, or looks at the list of
 /// state/other attribute affecting selectors.
-#[derive(Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Debug, MallocSizeOf)]
 pub struct InvalidationMap {
    /// A map from a given class name to all the selectors with that class
    /// selector.
--- a/components/style/invalidation/element/restyle_hints.rs
+++ b/components/style/invalidation/element/restyle_hints.rs
@ -230,9 +230,7 @@ impl From<nsRestyleHint> for RestyleHint {
 }

 #[cfg(feature = "servo")]
-impl ::heapsize::HeapSizeOf for RestyleHint {
-    fn heap_size_of_children(&self) -> usize { 0 }
-}
+malloc_size_of_is_0!(RestyleHint);

 /// Asserts that all replacement hints have a matching nsRestyleHint value.
 #[cfg(feature = "gecko")]
--- a/components/style/invalidation/media_queries.rs
+++ b/components/style/invalidation/media_queries.rs
@ -23,9 +23,7 @@ use stylesheets::{NestedRuleIterationCondition, Stylesheet, SupportsRule};
 ///
 /// If this changes, though, we may need to remove the item from the cache if
 /// present before it goes away.
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
 pub struct MediaListKey(usize);

 impl MediaListKey {
@ -53,9 +51,7 @@ impl ToMediaListKey for MediaRule {}

 /// A struct that holds the result of a media query evaluation pass for the
 /// media queries that evaluated successfully.
-#[derive(Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Debug, MallocSizeOf, PartialEq)]
 pub struct EffectiveMediaQueryResults {
    /// The set of media lists that matched last time.
    set: FnvHashSet<MediaListKey>,
--- a/components/style/invalidation/stylesheets.rs
+++ b/components/style/invalidation/stylesheets.rs
@ -24,7 +24,7 @@ use stylesheets::{CssRule, StylesheetInDocument};
 /// element is determined by whether the invalidation is stored in the
 /// StylesheetInvalidationSet's invalid_scopes or invalid_elements table.
 #[derive(Debug, Eq, Hash, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 enum Invalidation {
    /// An element with a given id.
    ID(Atom),
@ -75,7 +75,7 @@ impl Invalidation {
 ///
 /// TODO(emilio): We might be able to do the same analysis for media query
 /// changes too (or even selector changes?).
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct StylesheetInvalidationSet {
    /// The subtrees we know we have to restyle so far.
    invalid_scopes: FnvHashSet<Invalidation>,
--- a/components/style/lib.rs
+++ b/components/style/lib.rs
@ -50,8 +50,6 @@ extern crate fallible;
 extern crate fnv;
 #[cfg(feature = "gecko")] #[macro_use] pub mod gecko_string_cache;
 extern crate hashglobe;
-#[cfg(feature = "servo")] extern crate heapsize;
-#[cfg(feature = "servo")] #[macro_use] extern crate heapsize_derive;
 extern crate itertools;
 extern crate itoa;
 #[cfg(feature = "servo")] #[macro_use] extern crate html5ever;
@ -60,8 +58,8 @@ extern crate lazy_static;
 #[macro_use]
 extern crate log;
 extern crate lru_cache;
-#[cfg(feature = "gecko")] #[macro_use] extern crate malloc_size_of;
-#[cfg(feature = "gecko")] #[macro_use] extern crate malloc_size_of_derive;
+#[macro_use] extern crate malloc_size_of;
+#[macro_use] extern crate malloc_size_of_derive;
 #[allow(unused_extern_crates)]
 #[macro_use]
 extern crate matches;
--- a/components/style/logical_geometry.rs
+++ b/components/style/logical_geometry.rs
@ -24,7 +24,7 @@ pub enum InlineBaseDirection {

 // TODO: improve the readability of the WritingMode serialization, refer to the Debug:fmt()
 bitflags!(
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf, Serialize))]
+    #[cfg_attr(feature = "servo", derive(MallocSizeOf, Serialize))]
    pub flags WritingMode: u8 {
        const FLAG_RTL = 1 << 0,
        const FLAG_VERTICAL = 1 << 1,
--- a/components/style/macros.rs
+++ b/components/style/macros.rs
@ -47,9 +47,8 @@ macro_rules! define_numbered_css_keyword_enum {
    };
    ($name: ident: $( $css: expr => $variant: ident = $value: expr ),+) => {
        #[allow(non_camel_case_types, missing_docs)]
-        #[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+        #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Ord, PartialEq, PartialOrd)]
+        #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
        pub enum $name {
            $( $variant = $value ),+
        }
@ -103,9 +102,7 @@ macro_rules! add_impls_for_keyword_enum {
 macro_rules! define_keyword_type {
    ($name: ident, $css: expr) => {
        #[allow(missing_docs)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(Animate, Clone, ComputeSquaredDistance, Copy, PartialEq)]
+        #[derive(Animate, Clone, ComputeSquaredDistance, Copy, MallocSizeOf, PartialEq)]
        #[derive(ToAnimatedZero, ToComputedValue, ToCss)]
        pub struct $name;

--- a/components/style/media_queries.rs
+++ b/components/style/media_queries.rs
@ -26,7 +26,7 @@ pub use gecko::media_queries::{Device, Expression};

 /// A type that encapsulates a media query list.
 #[derive(Clone, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct MediaList {
    /// The list of media queries.
    pub media_queries: Vec<MediaQuery>,
@ -48,7 +48,7 @@ impl MediaList {
 }

 /// <https://drafts.csswg.org/mediaqueries/#mq-prefix>
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Clone, Copy, Debug, Eq, PartialEq, ToCss)]
 pub enum Qualifier {
    /// Hide a media query from legacy UAs:
@ -63,7 +63,7 @@ pub enum Qualifier {
 ///
 /// [mq]: https://drafts.csswg.org/mediaqueries/
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct MediaQuery {
    /// The qualifier for this query.
    pub qualifier: Option<Qualifier>,
@ -135,7 +135,7 @@ impl ToCss for MediaQuery {

 /// <http://dev.w3.org/csswg/mediaqueries-3/#media0>
 #[derive(Clone, Debug, Eq, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum MediaQueryType {
    /// A media type that matches every device.
    All,
@ -164,7 +164,7 @@ impl MediaQueryType {

 /// <https://drafts.csswg.org/mediaqueries/#media-types>
 #[derive(Clone, Debug, Eq, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct MediaType(pub CustomIdent);

 impl MediaType {
--- a/components/style/properties/declaration_block.rs
+++ b/components/style/properties/declaration_block.rs
@ -40,9 +40,7 @@ impl AnimationRules {
 }

 /// Whether a given declaration comes from CSS parsing, or from CSSOM.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
 pub enum DeclarationSource {
    /// The declaration was obtained from CSS parsing of sheets and such.
    Parsing,
@ -53,9 +51,7 @@ pub enum DeclarationSource {
 /// A declaration [importance][importance].
 ///
 /// [importance]: https://drafts.csswg.org/css-cascade/#importance
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
 pub enum Importance {
    /// Indicates a declaration without `!important`.
    Normal,
--- a/components/style/properties/helpers.mako.rs
+++ b/components/style/properties/helpers.mako.rs
@ -117,9 +117,7 @@
            use values::computed::ComputedVecIter;

            /// The computed value, effectively a list of single values.
-            #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-            #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-            #[derive(Clone, Debug, PartialEq)]
+            #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
            % if need_animatable or animation_value_type == "ComputedValue":
            #[derive(Animate, ComputeSquaredDistance)]
            % endif
@ -178,9 +176,7 @@
        }

        /// The specified value of ${name}.
-        #[derive(Clone, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
        pub struct SpecifiedValue(pub Vec<single_value::SpecifiedValue>);

        impl ToCss for SpecifiedValue {
@ -950,9 +946,7 @@
            pub type T = ::values::computed::${length_type};
        }

-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(Clone, Debug, PartialEq, ToCss)]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
        pub struct SpecifiedValue(pub ${length_type});

        % if length_type == "MozLength":
--- a/components/style/properties/helpers/animated_properties.mako.rs
+++ b/components/style/properties/helpers/animated_properties.mako.rs
@ -77,9 +77,7 @@ pub fn nscsspropertyid_is_animatable(property: nsCSSPropertyID) -> bool {
 /// a shorthand with at least one transitionable longhand component, or an unsupported property.
 // NB: This needs to be here because it needs all the longhands generated
 // beforehand.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
 pub enum TransitionProperty {
    /// All, any transitionable property changing should generate a transition.
    ///
@ -203,7 +201,7 @@ pub fn nscsspropertyid_is_transitionable(property: nsCSSPropertyID) -> bool {
 /// property.
 #[cfg(feature = "servo")]
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum AnimatedProperty {
    % for prop in data.longhands:
        % if prop.animatable:
@ -339,7 +337,7 @@ unsafe impl HasSimpleFFI for AnimationValueMap {}
 /// FIXME: We need to add a path for custom properties, but that's trivial after
 /// this (is a similar path to that of PropertyDeclaration).
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum AnimationValue {
    % for prop in data.longhands:
        % if prop.animatable:
@ -1190,7 +1188,7 @@ fn rotate_to_matrix(x: f32, y: f32, z: f32, a: Angle) -> ComputedMatrix {

 /// A 2d matrix for interpolation.
 #[derive(Clone, ComputeSquaredDistance, Copy, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[allow(missing_docs)]
 // FIXME: We use custom derive for ComputeSquaredDistance. However, If possible, we should convert
 // the InnerMatrix2D into types with physical meaning. This custom derive computes the squared
@ -1202,18 +1200,18 @@ pub struct InnerMatrix2D {
 }

 /// A 2d translation function.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
 pub struct Translate2D(f32, f32);

 /// A 2d scale function.
 #[derive(Clone, ComputeSquaredDistance, Copy, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct Scale2D(f32, f32);

 /// A decomposed 2d matrix.
 #[derive(Clone, Copy, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct MatrixDecomposed2D {
    /// The translation function.
    pub translate: Translate2D,
@ -1497,33 +1495,33 @@ impl From<ComputedMatrix> for RawGeckoGfxMatrix4x4 {
 }

 /// A 3d translation.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
 pub struct Translate3D(f32, f32, f32);

 /// A 3d scale function.
 #[derive(Clone, ComputeSquaredDistance, Copy, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct Scale3D(f32, f32, f32);

 /// A 3d skew function.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Animate, Clone, Copy, Debug)]
 pub struct Skew(f32, f32, f32);

 /// A 3d perspective transformation.
 #[derive(Clone, ComputeSquaredDistance, Copy, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct Perspective(f32, f32, f32, f32);

 /// A quaternion used to represent a rotation.
 #[derive(Clone, Copy, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct Quaternion(f64, f64, f64, f64);

 /// A decomposed 3d matrix.
 #[derive(Clone, ComputeSquaredDistance, Copy, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct MatrixDecomposed3D {
    /// A translation function.
    pub translate: Translate3D,
--- a/components/style/properties/longhand/background.mako.rs
+++ b/components/style/properties/longhand/background.mako.rs
@ -52,9 +52,7 @@ ${helpers.predefined_type("background-image", "ImageLayer",
                             "round" => Round,
                             "no-repeat" => NoRepeat);

-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    #[derive(Clone, Debug, PartialEq, ToCss)]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
    pub enum SpecifiedValue {
        RepeatX,
        RepeatY,
@ -64,9 +62,7 @@ ${helpers.predefined_type("background-image", "ImageLayer",
    pub mod computed_value {
        pub use super::RepeatKeyword;

-        #[derive(Clone, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
        pub struct T(pub RepeatKeyword, pub RepeatKeyword);
    }

--- a/components/style/properties/longhand/border.mako.rs
+++ b/components/style/properties/longhand/border.mako.rs
@ -81,15 +81,11 @@ ${helpers.gecko_keyword_conversion(Keyword('border-style',

        pub mod computed_value {
            use cssparser::RGBA;
-            #[derive(Clone, Debug, PartialEq)]
-            #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-            #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+            #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
            pub struct T(pub Option<Vec<RGBA>>);
        }

-        #[derive(Clone, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
        pub enum SpecifiedValue {
            None,
            Colors(Vec<RGBAColor>),
@ -232,15 +228,11 @@ ${helpers.predefined_type("border-image-outset", "LengthOrNumberRect",
    pub mod computed_value {
        pub use super::RepeatKeyword;

-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(Clone, Debug, PartialEq, ToCss)]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
        pub struct T(pub RepeatKeyword, pub RepeatKeyword);
    }

-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    #[derive(Clone, Debug, PartialEq, ToCss)]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
    pub struct SpecifiedValue(pub RepeatKeyword,
                              pub Option<RepeatKeyword>);

--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhand/box.mako.rs
@ -162,9 +162,8 @@
    }

    #[allow(non_camel_case_types)]
-    #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, ToComputedValue)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+    #[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, PartialEq, ToComputedValue)]
+    #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
    pub enum SpecifiedValue {
        % for value in values:
            ${to_rust_ident(value)},
@ -460,9 +459,7 @@ ${helpers.predefined_type("transition-delay",
        pub use super::SpecifiedValue as T;
    }

-    #[derive(Clone, Debug, Eq, Hash, PartialEq, ToComputedValue)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq, ToComputedValue)]
    pub struct SpecifiedValue(pub Option<KeyframesName>);

    impl SpecifiedValue {
@ -555,9 +552,7 @@ ${helpers.predefined_type("animation-timing-function",
    }

    // https://drafts.csswg.org/css-animations/#animation-iteration-count
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    #[derive(Clone, Debug, PartialEq, ToCss, ToComputedValue)]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss, ToComputedValue)]
    pub enum SpecifiedValue {
        Number(f32),
        Infinite,
@ -689,9 +684,7 @@ ${helpers.predefined_type(
        use values::computed;
        use values::computed::{Length, LengthOrPercentage};

-        #[derive(Clone, Copy, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
        pub struct ComputedMatrix {
            pub m11: CSSFloat, pub m12: CSSFloat, pub m13: CSSFloat, pub m14: CSSFloat,
            pub m21: CSSFloat, pub m22: CSSFloat, pub m23: CSSFloat, pub m24: CSSFloat,
@ -699,9 +692,7 @@ ${helpers.predefined_type(
            pub m41: CSSFloat, pub m42: CSSFloat, pub m43: CSSFloat, pub m44: CSSFloat,
        }

-        #[derive(Clone, Copy, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
        pub struct ComputedMatrixWithPercents {
            pub m11: CSSFloat, pub m12: CSSFloat, pub m13: CSSFloat, pub m14: CSSFloat,
            pub m21: CSSFloat, pub m22: CSSFloat, pub m23: CSSFloat, pub m24: CSSFloat,
@ -733,9 +724,7 @@ ${helpers.predefined_type(
            }
        }

-        #[derive(Clone, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
        pub enum ComputedOperation {
            Matrix(ComputedMatrix),
            // For `-moz-transform` matrix and matrix3d.
@ -767,9 +756,7 @@ ${helpers.predefined_type(
                               count: computed::Integer },
        }

-        #[derive(Clone, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
        pub struct T(pub Option<Vec<ComputedOperation>>);
    }

@ -779,9 +766,7 @@ ${helpers.predefined_type(
    /// Multiple transform functions compose a transformation.
    ///
    /// Some transformations can be expressed by other more general functions.
-    #[derive(Clone, Debug, PartialEq)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
    pub enum SpecifiedOperation {
        /// Represents a 2D 2x3 matrix.
        Matrix(Matrix<Number>),
@ -970,9 +955,7 @@ ${helpers.predefined_type(
        }
    }

-    #[derive(Clone, Debug, PartialEq)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
    pub struct SpecifiedValue(Vec<SpecifiedOperation>);

    impl ToCss for SpecifiedValue {
@ -1688,9 +1671,7 @@ ${helpers.predefined_type("transform-origin",
    }

    bitflags! {
-        #[derive(ToComputedValue)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(MallocSizeOf, ToComputedValue)]
        pub flags SpecifiedValue: u8 {
            const LAYOUT = 0x01,
            const STYLE = 0x02,
@ -1829,9 +1810,7 @@ ${helpers.single_keyword("-moz-orient",
        pub use super::SpecifiedValue as T;
    }

-    #[derive(Clone, Debug, PartialEq, ToComputedValue)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
    pub enum SpecifiedValue {
        Auto,
        AnimateableFeatures(Vec<CustomIdent>),
--- a/components/style/properties/longhand/counters.mako.rs
+++ b/components/style/properties/longhand/counters.mako.rs
@ -36,9 +36,7 @@
        #[cfg(feature = "gecko")]
        use values::specified::Attr;

-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[derive(Clone, Debug, Eq, PartialEq, ToComputedValue)]
+        #[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
        pub enum ContentItem {
            /// Literal string content.
            String(String),
@ -98,9 +96,7 @@
            }
        }

-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(Clone, Debug, Eq, PartialEq, ToComputedValue)]
+        #[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
        pub enum T {
            Normal,
            None,
@ -249,9 +245,7 @@
        use style_traits::ToCss;
        use values::CustomIdent;

-        #[derive(Clone, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
        pub struct T(pub Vec<(CustomIdent, i32)>);

        impl ToCss for T {
--- a/components/style/properties/longhand/font.mako.rs
+++ b/components/style/properties/longhand/font.mako.rs
@ -91,25 +91,22 @@ macro_rules! impl_gecko_keyword_conversions {
        use Atom;
        pub use self::FontFamily as SingleComputedValue;

-        #[derive(Clone, Debug, Eq, Hash, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+        #[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
+        #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
        pub enum FontFamily {
            FamilyName(FamilyName),
            Generic(Atom),
        }

-        #[derive(Clone, Debug, Eq, Hash, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+        #[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
+        #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
        pub struct FamilyName {
            pub name: Atom,
            pub syntax: FamilyNameSyntax,
        }

-        #[derive(Clone, Debug, Eq, Hash, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+        #[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
+        #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
        pub enum FamilyNameSyntax {
            /// The family name was specified in a quoted form, e.g. "Font Name"
            /// or 'Font Name'.
@ -334,7 +331,7 @@ macro_rules! impl_gecko_keyword_conversions {
        }

        #[cfg(feature = "servo")]
-        #[derive(Clone, Debug, Eq, Hash, HeapSizeOf, PartialEq)]
+        #[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
        pub struct FontFamilyList(Vec<FontFamily>);

        #[cfg(feature = "gecko")]
@ -460,7 +457,7 @@ macro_rules! impl_gecko_keyword_conversions {
        }

        #[derive(Clone, Debug, Eq, Hash, PartialEq)]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
        pub struct T(pub FontFamilyList);

        #[cfg(feature = "gecko")]
@ -625,9 +622,7 @@ ${helpers.single_keyword_system("font-variant-caps",
    use properties::longhands::system_font::SystemFont;


-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    #[derive(Clone, Copy, Debug, Eq, PartialEq, ToCss)]
+    #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
    pub enum SpecifiedValue {
        Normal,
        Bold,
@ -679,9 +674,9 @@ ${helpers.single_keyword_system("font-variant-caps",
        ///
        /// However, system fonts may provide other values. Pango
        /// may provide 350, 380, and 1000 (on top of the existing values), for example.
-        #[derive(Clone, ComputeSquaredDistance, Copy, Debug, Eq, Hash, PartialEq, ToCss)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+        #[derive(Clone, ComputeSquaredDistance, Copy, Debug, Eq, Hash, MallocSizeOf, PartialEq,
+                 ToCss)]
+        #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
        pub struct T(pub u16);

        impl T {
@ -927,9 +922,7 @@ ${helpers.single_keyword_system("font-variant-caps",
    use properties::longhands::system_font::SystemFont;


-    #[derive(Clone, Copy, Debug, PartialEq, ToCss)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
    pub enum SpecifiedValue {
        None,
        Number(specified::Number),
@ -976,9 +969,8 @@ ${helpers.single_keyword_system("font-variant-caps",
        use values::CSSFloat;
        use values::animated::{ToAnimatedValue, ToAnimatedZero};

-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, PartialEq, ToCss)]
+        #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq,
+                 ToCss)]
        pub enum T {
            #[animation(error)]
            None,
@ -1051,9 +1043,7 @@ ${helpers.single_keyword_system("font-variant-caps",
        pub use super::SpecifiedValue as T;
    }

-    #[derive(Clone, Debug, PartialEq, ToComputedValue)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
    pub struct SpecifiedValue {
        pub weight: bool,
        pub style: bool,
@ -1159,9 +1149,7 @@ ${helpers.single_keyword_system("font-kerning",
    use values::CustomIdent;


-    #[derive(Clone, Debug, PartialEq)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
    pub enum VariantAlternates {
        Stylistic(CustomIdent),
        Styleset(Box<[CustomIdent]>),
@ -1172,14 +1160,10 @@ ${helpers.single_keyword_system("font-kerning",
        HistoricalForms,
    }

-    #[derive(Clone, Debug, PartialEq)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
    pub struct VariantAlternatesList(pub Box<[VariantAlternates]>);

-    #[derive(Clone, Debug, PartialEq, ToCss)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
    pub enum SpecifiedValue {
        Value(VariantAlternatesList),
        System(SystemFont)
@ -1268,7 +1252,7 @@ ${helpers.single_keyword_system("font-kerning",
    }

    bitflags! {
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
        pub flags ParsingFlags: u8 {
            const NORMAL = 0,
            const HISTORICAL_FORMS = 0x01,
@ -1375,8 +1359,7 @@ macro_rules! exclusive_value {


    bitflags! {
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(MallocSizeOf)]
        pub flags VariantEastAsian: u16 {
            const NORMAL = 0,
            const JIS78 = 0x01,
@ -1521,8 +1504,7 @@ macro_rules! exclusive_value {


    bitflags! {
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(MallocSizeOf)]
        pub flags VariantLigatures: u16 {
            const NORMAL = 0,
            const NONE = 0x01,
@ -1681,8 +1663,7 @@ macro_rules! exclusive_value {


    bitflags! {
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(MallocSizeOf)]
        pub flags VariantNumeric: u8 {
            const NORMAL = 0,
            const LINING_NUMS = 0x01,
@ -1907,9 +1888,7 @@ https://drafts.csswg.org/css-fonts-4/#low-level-font-variation-settings-control-
    use style_traits::ToCss;
    use byteorder::{BigEndian, ByteOrder};

-    #[derive(Clone, Debug, Eq, PartialEq)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq)]
    pub enum SpecifiedValue {
        Normal,
        Override(String),
@ -1965,9 +1944,7 @@ https://drafts.csswg.org/css-fonts-4/#low-level-font-variation-settings-control-
        // OpenType "language system" tag, so we should be able to compute
        // it and store it as a 32-bit integer
        // (see http://www.microsoft.com/typography/otspec/languagetags.htm).
-        #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq)]
        pub struct T(pub u32);
    }

@ -2074,9 +2051,7 @@ https://drafts.csswg.org/css-fonts-4/#low-level-font-variation-settings-control-
            }
        }

-        #[derive(Clone, Debug, PartialEq, ToComputedValue)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
        pub struct T(pub Atom);
    }

@ -2278,9 +2253,7 @@ ${helpers.single_keyword("-moz-math-variant",
            }
        }

-        #[derive(Clone, Debug, PartialEq, ToComputedValue)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
        /// text-zoom. Enable if true, disable if false
        pub struct T(pub bool);
    }
@ -2473,7 +2446,7 @@ ${helpers.single_keyword("-moz-math-variant",
        // dummy system font module that does nothing

        #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, ToCss)]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
        /// void enum for system font, can never exist
        pub enum SystemFont {}
        impl SystemFont {
--- a/components/style/properties/longhand/inherited_box.mako.rs
+++ b/components/style/properties/longhand/inherited_box.mako.rs
@ -70,9 +70,7 @@ ${helpers.single_keyword("image-rendering",
    use std::f64::consts::PI;
    const TWO_PI: f64 = 2.0 * PI;

-    #[derive(Clone, Copy, Debug, PartialEq)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
    pub struct SpecifiedValue {
        pub angle: Option<Angle>,
        pub flipped: bool
@ -102,9 +100,7 @@ ${helpers.single_keyword("image-rendering",
        use style_traits::ToCss;
        use values::specified::Angle;

-        #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq)]
        pub enum Orientation {
            Angle0 = 0,
            Angle90,
@ -135,9 +131,7 @@ ${helpers.single_keyword("image-rendering",
            }
        }

-        #[derive(Clone, Copy, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
        pub enum T {
            FromImage,
            AngleWithFlipped(Orientation, bool),
--- a/components/style/properties/longhand/inherited_svg.mako.rs
+++ b/components/style/properties/longhand/inherited_svg.mako.rs
@ -166,9 +166,7 @@ ${helpers.predefined_type("marker-end", "UrlOrNone", "Either::Second(None_)",
    ///
    /// Higher priority values, i.e. the values specified first,
    /// will be painted first (and may be covered by paintings of lower priority)
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    #[derive(Clone, Copy, Debug, PartialEq, ToComputedValue)]
+    #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
    pub struct SpecifiedValue(pub u8);

    impl SpecifiedValue {
--- a/components/style/properties/longhand/inherited_text.mako.rs
+++ b/components/style/properties/longhand/inherited_text.mako.rs
@ -285,9 +285,7 @@ ${helpers.predefined_type("word-spacing",
    use std::fmt;
    use style_traits::ToCss;

-    #[derive(Clone, Copy, Debug, Default, PartialEq)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Copy, Debug, Default, MallocSizeOf, PartialEq)]
    pub struct SpecifiedValue {
        pub underline: bool,
        pub overline: bool,
@ -408,36 +406,29 @@ ${helpers.predefined_type(


    pub mod computed_value {
-        #[derive(Clone, Debug, PartialEq, ToCss)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf, ToComputedValue))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+        #[cfg_attr(feature = "servo", derive(ToComputedValue))]
        pub enum T {
            Keyword(KeywordValue),
            None,
            String(String),
        }

-        #[derive(Clone, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
        pub struct KeywordValue {
            pub fill: bool,
            pub shape: super::ShapeKeyword,
        }
    }

-    #[derive(Clone, Debug, PartialEq, ToCss)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
    pub enum SpecifiedValue {
        Keyword(KeywordValue),
        None,
        String(String),
    }

-    #[derive(Clone, Debug, PartialEq)]
-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
    pub enum KeywordValue {
        Fill(bool),
        Shape(ShapeKeyword),
@ -604,9 +595,7 @@ ${helpers.predefined_type(
                             "left" => Left);
    add_impls_for_keyword_enum!(HorizontalWritingModeValue);

-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    #[derive(Clone, Debug, PartialEq, ToComputedValue, ToCss)]
+    #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
    pub struct SpecifiedValue(pub HorizontalWritingModeValue, pub VerticalWritingModeValue);

    pub mod computed_value {
--- a/components/style/properties/longhand/list.mako.rs
+++ b/components/style/properties/longhand/list.mako.rs
@ -104,9 +104,7 @@ ${helpers.single_keyword("list-style-position", "outside inside", animation_valu
    pub mod computed_value {
        use values::specified::UrlOrNone;

-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(Clone, Debug, PartialEq, ToCss)]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
        pub struct T(pub UrlOrNone);

        // FIXME(nox): This is wrong, there are different types for specified
@ -146,9 +144,7 @@ ${helpers.single_keyword("list-style-position", "outside inside", animation_valu
    pub use self::computed_value::T as SpecifiedValue;

    pub mod computed_value {
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(Clone, Debug, PartialEq, ToComputedValue)]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
        pub struct T(pub Vec<(String, String)>);
    }

--- a/components/style/properties/longhand/pointing.mako.rs
+++ b/components/style/properties/longhand/pointing.mako.rs
@ -21,9 +21,7 @@
        #[cfg(feature = "gecko")]
        use values::specified::url::SpecifiedUrl;

-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
+        #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
        pub enum Keyword {
            Auto,
            Cursor(Cursor),
--- a/components/style/properties/longhand/position.mako.rs
+++ b/components/style/properties/longhand/position.mako.rs
@ -294,17 +294,13 @@ ${helpers.predefined_type("object-position",
    pub type SpecifiedValue = computed_value::T;

    pub mod computed_value {
-        #[derive(Clone, Copy, Debug, Eq, PartialEq, ToComputedValue)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
        pub enum AutoFlow {
            Row,
            Column,
        }

-        #[derive(Clone, Copy, Debug, Eq, PartialEq, ToComputedValue)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
        pub struct T {
            pub autoflow: AutoFlow,
            pub dense: bool,
--- a/components/style/properties/longhand/table.mako.rs
+++ b/components/style/properties/longhand/table.mako.rs
@ -19,9 +19,7 @@ ${helpers.single_keyword("table-layout", "auto fixed",
        use std::fmt;
        use style_traits::ToCss;

-        #[derive(Clone, Copy, Debug, PartialEq, ToComputedValue)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
        pub struct T(pub i32);

        impl ToCss for T {
--- a/components/style/properties/longhand/text.mako.rs
+++ b/components/style/properties/longhand/text.mako.rs
@ -19,18 +19,14 @@
    use style_traits::ToCss;


-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    #[derive(Clone, Debug, Eq, PartialEq, ToCss)]
+    #[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
    pub enum Side {
        Clip,
        Ellipsis,
        String(Box<str>),
    }

-    #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    #[derive(Clone, Debug, Eq, PartialEq, ToCss)]
+    #[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
    pub struct SpecifiedValue {
        pub first: Side,
        pub second: Option<Side>
@ -39,9 +35,7 @@
    pub mod computed_value {
        pub use super::Side;

-        #[derive(Clone, Debug, PartialEq)]
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
        pub struct T {
            // When the specified value only has one side, that's the "second"
            // side, and the sides are logical, so "second" means "end".  The
@ -153,9 +147,7 @@ ${helpers.single_keyword("unicode-bidi",
    use style_traits::ToCss;

    bitflags! {
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(ToComputedValue)]
+        #[derive(MallocSizeOf, ToComputedValue)]
        pub flags SpecifiedValue: u8 {
            const NONE = 0,
            const UNDERLINE = 0x01,
--- a/components/style/properties/longhand/ui.mako.rs
+++ b/components/style/properties/longhand/ui.mako.rs
@ -48,9 +48,7 @@ ${helpers.single_keyword("-moz-window-shadow", "none default menu tooltip sheet"
    use style_traits::ToCss;

    pub mod computed_value {
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        #[derive(Clone, Copy, Debug, PartialEq, ToComputedValue)]
+        #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
        pub struct T(pub bool);
    }

--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@ -250,9 +250,7 @@ static ${name}: LonghandIdSet = LonghandIdSet {
 </%def>

 /// A set of longhand properties
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 pub struct LonghandIdSet {
    storage: [u32; (${len(data.longhands)} - 1 + 32) / 32]
 }
@ -400,9 +398,7 @@ impl PropertyDeclarationIdSet {
 }

 /// An enum to represent a CSS Wide keyword.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, Eq, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
 pub enum CSSWideKeyword {
    /// The `initial` keyword.
    Initial,
@ -465,9 +461,7 @@ bitflags! {
 }

 /// An identifier for a given longhand property.
-#[derive(Clone, Copy, Eq, Hash, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Eq, Hash, MallocSizeOf, PartialEq)]
 pub enum LonghandId {
    % for i, property in enumerate(data.longhands):
        /// ${property.name}
@ -731,9 +725,7 @@ impl LonghandId {
 }

 /// An identifier for a given shorthand property.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, PartialEq, ToCss)]
 pub enum ShorthandId {
    % for property in data.shorthands:
        /// ${property.name}
@ -1022,7 +1014,7 @@ impl<'a, T: ToCss> ToCss for DeclaredValue<'a, T> {
 /// An identifier for a given property declaration, which can be either a
 /// longhand or a custom property.
 #[derive(Clone, Copy, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum PropertyDeclarationId<'a> {
    /// A longhand.
    Longhand(LonghandId),
@ -1810,12 +1802,10 @@ pub mod style_structs {

    % for style_struct in data.active_style_structs():
        % if style_struct.name == "Font":
-        #[derive(Clone, Debug)]
+        #[derive(Clone, Debug, MallocSizeOf)]
        % else:
-        #[derive(Clone, Debug, PartialEq)]
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq)]
        % endif
-        #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
        /// The ${style_struct.name} style struct.
        pub struct ${style_struct.name} {
            % for longhand in style_struct.longhands:
@ -3575,7 +3565,7 @@ pub fn adjust_border_width(style: &mut StyleBuilder) {

 /// An identifier for a given alias property.
 #[derive(Clone, Copy, Eq, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum AliasId {
    % for i, property in enumerate(data.all_aliases()):
        /// ${property.name}
--- a/components/style/rule_tree/mod.rs
+++ b/components/style/rule_tree/mod.rs
@ -9,8 +9,6 @@
 use applicable_declarations::ApplicableDeclarationList;
 #[cfg(feature = "gecko")]
 use gecko::selector_parser::PseudoElement;
-#[cfg(feature = "servo")]
-use heapsize::HeapSizeOf;
 #[cfg(feature = "gecko")]
 use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
 use properties::{Importance, LonghandIdSet, PropertyDeclarationBlock};
@ -46,7 +44,7 @@ use thread_state;
 /// logs from http://logs.glob.uno/?c=mozilla%23servo&s=3+Apr+2017&e=3+Apr+2017#c644094
 /// to se a discussion about the different memory orderings used here.
 #[derive(Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct RuleTree {
    root: StrongRuleNode,
 }
@ -463,7 +461,7 @@ const RULE_TREE_GC_INTERVAL: usize = 300;
 /// [1]: https://drafts.csswg.org/css-cascade/#cascade-origin
 #[repr(u8)]
 #[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum CascadeLevel {
    /// Normal User-Agent rules.
    UANormal = 0,
@ -827,10 +825,7 @@ pub struct StrongRuleNode {
 }

 #[cfg(feature = "servo")]
-impl HeapSizeOf for StrongRuleNode {
-    fn heap_size_of_children(&self) -> usize { 0 }
-}
-
+malloc_size_of_is_0!(StrongRuleNode);

 impl StrongRuleNode {
    fn new(n: Box<RuleNode>) -> Self {
--- a/components/style/selector_map.rs
+++ b/components/style/selector_map.rs
@ -94,9 +94,7 @@ pub trait SelectorMapEntry : Sized + Clone {
 /// * https://bugzilla.mozilla.org/show_bug.cgi?id=681755
 ///
 /// TODO: Tune the initial capacity of the HashMap
-#[derive(Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Debug, MallocSizeOf)]
 pub struct SelectorMap<T: 'static> {
    /// A hash from an ID to rules which contain that ID selector.
    pub id_hash: MaybeCaseInsensitiveHashMap<Atom, SmallVec<[T; 1]>>,
@ -465,9 +463,7 @@ fn find_bucket<'a>(mut iter: SelectorIter<'a, SelectorImpl>) -> Bucket<'a> {
 }

 /// Wrapper for PrecomputedHashMap that does ASCII-case-insensitive lookup in quirks mode.
-#[derive(Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Debug, MallocSizeOf)]
 pub struct MaybeCaseInsensitiveHashMap<K: PrecomputedHash + Hash + Eq, V: 'static>(PrecomputedDiagnosticHashMap<K, V>);

 // FIXME(Manishearth) the 'static bound can be removed when
--- a/components/style/selector_parser.rs
+++ b/components/style/selector_parser.rs
@ -35,7 +35,7 @@ pub use servo::restyle_damage::ServoRestyleDamage as RestyleDamage;
 pub use gecko::restyle_damage::GeckoRestyleDamage as RestyleDamage;

 /// Servo's selector parser.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct SelectorParser<'a> {
    /// The origin of the stylesheet we're parsing.
    pub stylesheet_origin: Origin,
@ -103,8 +103,7 @@ pub enum PseudoElementCascadeType {
 }

 /// A per-functional-pseudo map, from a given pseudo to a `T`.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(MallocSizeOf)]
 pub struct PerPseudoElementMap<T> {
    entries: [Option<T>; SIMPLE_PSEUDO_COUNT],
 }
--- a/components/style/servo/media_queries.rs
+++ b/components/style/servo/media_queries.rs
@ -27,7 +27,7 @@ use values::specified;
 /// is displayed in.
 ///
 /// This is the struct against which media queries are evaluated.
-#[derive(HeapSizeOf)]
+#[derive(MallocSizeOf)]
 pub struct Device {
    /// The current media type used by de device.
    media_type: MediaType,
@ -44,14 +44,14 @@ pub struct Device {
    /// other style being computed at the same time, given we need the style of
    /// the parent to compute everything else. So it is correct to just use
    /// a relaxed atomic here.
-    #[ignore_heap_size_of = "Pure stack type"]
+    #[ignore_malloc_size_of = "Pure stack type"]
    root_font_size: AtomicIsize,
    /// Whether any styles computed in the document relied on the root font-size
    /// by using rem units.
-    #[ignore_heap_size_of = "Pure stack type"]
+    #[ignore_malloc_size_of = "Pure stack type"]
    used_root_font_size: AtomicBool,
    /// Whether any styles computed in the document relied on the viewport size.
-    #[ignore_heap_size_of = "Pure stack type"]
+    #[ignore_malloc_size_of = "Pure stack type"]
    used_viewport_units: AtomicBool,
 }

@ -153,7 +153,7 @@ impl Device {
 ///
 /// Only `pub` for unit testing, please don't use it directly!
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum ExpressionKind {
    /// <http://dev.w3.org/csswg/mediaqueries-3/#width>
    Width(Range<specified::Length>),
@ -163,7 +163,7 @@ pub enum ExpressionKind {
 ///
 /// <http://dev.w3.org/csswg/mediaqueries-3/#media1>
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct Expression(pub ExpressionKind);

 impl Expression {
@ -240,7 +240,7 @@ impl ToCss for Expression {
 /// Only public for testing, implementation details of `Expression` may change
 /// for Stylo.
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum Range<T> {
    /// At least the inner value.
    Min(T),
--- a/components/style/servo/restyle_damage.rs
+++ b/components/style/servo/restyle_damage.rs
@ -8,7 +8,6 @@
 #![deny(missing_docs)]

 use computed_values::display;
-use heapsize::HeapSizeOf;
 use matching::{StyleChange, StyleDifference};
 use properties::ComputedValues;
 use std::fmt;
@ -53,9 +52,7 @@ bitflags! {
    }
 }

-impl HeapSizeOf for ServoRestyleDamage {
-    fn heap_size_of_children(&self) -> usize { 0 }
-}
+malloc_size_of_is_0!(ServoRestyleDamage);

 impl ServoRestyleDamage {
    /// Compute the `StyleDifference` (including the appropriate restyle damage)
--- a/components/style/servo/selector_parser.rs
+++ b/components/style/servo/selector_parser.rs
@ -30,7 +30,7 @@ use style_traits::{ParseError, StyleParseErrorKind};
 ///
 /// NB: If you add to this list, be sure to update `each_simple_pseudo_element` too.
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[allow(missing_docs)]
 #[repr(usize)]
 pub enum PseudoElement {
@ -251,7 +251,7 @@ pub type PseudoClassStringArg = Box<str>;
 /// A non tree-structural pseudo-class.
 /// See https://drafts.csswg.org/selectors-4/#structural-pseudos
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[allow(missing_docs)]
 pub enum NonTSPseudoClass {
    Active,
@ -368,7 +368,7 @@ impl NonTSPseudoClass {
 /// The abstract struct we implement the selector parser implementation on top
 /// of.
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct SelectorImpl;

 impl ::selectors::SelectorImpl for SelectorImpl {
@ -601,7 +601,7 @@ impl DerefMut for SnapshotMap {

 /// Servo's version of an element snapshot.
 #[derive(Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct ServoElementSnapshot {
    /// The stored state of the element.
    pub state: Option<ElementState>,
--- a/components/style/servo/url.rs
+++ b/components/style/servo/url.rs
@ -22,7 +22,7 @@ use values::computed::{Context, ToComputedValue, ComputedUrl};
 ///
 /// However, this approach is still not necessarily optimal: See
 /// <https://bugzilla.mozilla.org/show_bug.cgi?id=1347435#c6>
-#[derive(Clone, Debug, Deserialize, HeapSizeOf, Serialize)]
+#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
 pub struct SpecifiedUrl {
    /// The original URI. This might be optional since we may insert computed
    /// values of images into the cascade directly, and we don't bother to
@ -30,6 +30,7 @@ pub struct SpecifiedUrl {
    ///
    /// Refcounted since cloning this should be cheap and data: uris can be
    /// really large.
+    #[ignore_malloc_size_of = "Arc"]
    original: Option<Arc<String>>,

    /// The resolved value for the url, if valid.
--- a/components/style/shared_lock.rs
+++ b/components/style/shared_lock.rs
@ -26,10 +26,10 @@ use stylesheets::Origin;
 /// but that may not be web-compatible and may need to be changed (at which
 /// point Servo could use AtomicRefCell too).
 #[derive(Clone)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct SharedRwLock {
    #[cfg(feature = "servo")]
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+    #[cfg_attr(feature = "servo", ignore_malloc_size_of = "Arc")]
    arc: Arc<RwLock<()>>,

    #[cfg(feature = "gecko")]
--- a/components/style/stylesheet_set.rs
+++ b/components/style/stylesheet_set.rs
@ -12,7 +12,7 @@ use std::slice;
 use stylesheets::{Origin, OriginSet, OriginSetIterator, PerOrigin, StylesheetInDocument};

 /// Entry for a StylesheetSet.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 struct StylesheetSetEntry<S>
 where
    S: StylesheetInDocument + PartialEq + 'static,
@ -103,7 +103,7 @@ where

 /// The validity of the data in a given cascade origin.
 #[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum OriginValidity {
    /// The origin is clean, all the data already there is valid, though we may
    /// have new sheets at the end.
@ -260,7 +260,7 @@ where
    }
 }

-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 struct SheetCollection<S>
 where
    S: StylesheetInDocument + PartialEq + 'static,
@ -366,7 +366,7 @@ where
 }

 /// The set of stylesheets effective for a given document.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct StylesheetSet<S>
 where
    S: StylesheetInDocument + PartialEq + 'static,
--- a/components/style/stylesheets/keyframes_rule.rs
+++ b/components/style/stylesheets/keyframes_rule.rs
@ -96,9 +96,7 @@ impl DeepCloneWithLock for KeyframesRule {

 /// A number from 0 to 1, indicating the percentage of the animation when this
 /// keyframe should run.
-#[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd)]
 pub struct KeyframePercentage(pub f32);

 impl ::std::cmp::Ord for KeyframePercentage {
@ -260,16 +258,14 @@ impl DeepCloneWithLock for Keyframe {
 /// declarations to apply.
 ///
 /// TODO: Find a better name for this?
-#[derive(Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Debug, MallocSizeOf)]
 pub enum KeyframesStepValue {
    /// A step formed by a declaration block specified by the CSS.
    Declarations {
        /// The declaration block per se.
        #[cfg_attr(feature = "gecko",
                   ignore_malloc_size_of = "XXX: Primary ref, measure if DMD says it's worthwhile")]
-        #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+        #[cfg_attr(feature = "servo", ignore_malloc_size_of = "Arc")]
        block: Arc<Locked<PropertyDeclarationBlock>>
    },
    /// A synthetic step computed from the current computed values at the time
@ -278,9 +274,7 @@ pub enum KeyframesStepValue {
 }

 /// A single step from a keyframe animation.
-#[derive(Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Debug, MallocSizeOf)]
 pub struct KeyframesStep {
    /// The percentage of the animation duration when this step starts.
    pub start_percentage: KeyframePercentage,
@ -350,9 +344,7 @@ impl KeyframesStep {
 /// of keyframes, in order.
 ///
 /// It only takes into account animable properties.
-#[derive(Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Debug, MallocSizeOf)]
 pub struct KeyframesAnimation {
    /// The difference steps of the animation.
    pub steps: Vec<KeyframesStep>,
--- a/components/style/stylesheets/origin.rs
+++ b/components/style/stylesheets/origin.rs
@ -12,7 +12,7 @@ use std::ops::BitOrAssign;
 /// <https://drafts.csswg.org/css-cascade/#cascading-origins>
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 #[repr(u8)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub enum Origin {
    /// <https://drafts.csswg.org/css-cascade/#cascade-origin-user-agent>
    UserAgent = 1 << 0,
@ -40,7 +40,7 @@ impl Origin {

 bitflags! {
    /// A set of origins. This is equivalent to Gecko's OriginFlags.
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
    pub flags OriginSet: u8 {
        /// <https://drafts.csswg.org/css-cascade/#cascade-origin-user-agent>
        const ORIGIN_USER_AGENT = Origin::UserAgent as u8,
@ -104,9 +104,7 @@ impl Iterator for OriginSetIterator {
 }

 /// An object that stores a `T` for each origin of the CSS cascade.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Debug, Default)]
+#[derive(Debug, Default, MallocSizeOf)]
 pub struct PerOrigin<T> {
    /// Data for `Origin::UserAgent`.
    pub user_agent: T,
--- a/components/style/stylesheets/rule_parser.rs
+++ b/components/style/stylesheets/rule_parser.rs
@ -100,9 +100,7 @@ pub enum State {
    Body = 4,
 }

-#[derive(Clone, Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf)]
 /// Vendor prefix.
 pub enum VendorPrefix {
    /// -moz prefix.
--- a/components/style/stylesheets/stylesheet.rs
+++ b/components/style/stylesheets/stylesheet.rs
@ -38,7 +38,7 @@ pub struct UserAgentStylesheets {
 /// A set of namespaces applying to a given stylesheet.
 ///
 /// The namespace id is used in gecko
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Debug, Default, MallocSizeOf)]
 #[allow(missing_docs)]
 pub struct Namespaces {
    pub default: Option<(Namespace, NamespaceId)>,
@ -275,9 +275,9 @@ impl StylesheetInDocument for Stylesheet {
 /// A simple wrapper over an `Arc<Stylesheet>`, with pointer comparison, and
 /// suitable for its use in a `StylesheetSet`.
 #[derive(Clone)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct DocumentStyleSheet(
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+    #[cfg_attr(feature = "servo", ignore_malloc_size_of = "Arc")]
    pub Arc<Stylesheet>
 );

--- a/components/style/stylesheets/viewport_rule.rs
+++ b/components/style/stylesheets/viewport_rule.rs
@ -78,7 +78,7 @@ macro_rules! declare_viewport_descriptor_inner {
        $number_of_variants: expr
    ) => {
        #[derive(Clone, Debug, PartialEq)]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
        #[allow(missing_docs)]
        pub enum ViewportDescriptor {
            $(
@ -140,7 +140,7 @@ trait FromMeta: Sized {
 /// * http://dev.w3.org/csswg/css-device-adapt/#min-max-width-desc
 /// * http://dev.w3.org/csswg/css-device-adapt/#extend-to-zoom
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[allow(missing_docs)]
 pub enum ViewportLength {
    Specified(LengthOrPercentageOrAuto),
@ -231,7 +231,7 @@ struct ViewportRuleParser<'a, 'b: 'a> {
 }

 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[allow(missing_docs)]
 pub struct ViewportDescriptorDeclaration {
    pub origin: Origin,
@ -330,7 +330,7 @@ impl<'a, 'b, 'i> DeclarationParser<'i> for ViewportRuleParser<'a, 'b> {

 /// A `@viewport` rule.
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct ViewportRule {
    /// The declarations contained in this @viewport rule.
    pub declarations: Vec<ViewportDescriptorDeclaration>
--- a/components/style/stylist.rs
+++ b/components/style/stylist.rs
@ -182,11 +182,11 @@ impl UserAgentCascadeData {

 /// All the computed information for a stylesheet.
 #[derive(Default)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 struct DocumentCascadeData {
    #[cfg_attr(
        feature = "servo",
-        ignore_heap_size_of = "Arc, owned by UserAgentCascadeDataCache"
+        ignore_malloc_size_of = "Arc, owned by UserAgentCascadeDataCache"
    )]
    user_agent: Arc<UserAgentCascadeData>,
    user: CascadeData,
@ -338,7 +338,7 @@ impl DocumentCascadeData {

 /// A wrapper over a StylesheetSet that can be `Sync`, since it's only used and
 /// exposed via mutable methods in the `Stylist`.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 struct StylistStylesheetSet(StylesheetSet<StylistSheet>);
 // Read above to see why this is fine.
 unsafe impl Sync for StylistStylesheetSet {}
@ -370,7 +370,7 @@ impl ops::DerefMut for StylistStylesheetSet {
 ///
 /// This structure is effectively created once per pipeline, in the
 /// LayoutThread corresponding to that pipeline.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct Stylist {
    /// Device that the stylist is currently evaluating against.
    ///
@ -393,7 +393,7 @@ pub struct Stylist {
    stylesheets: StylistStylesheetSet,

    /// If true, the quirks-mode stylesheet is applied.
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "defined in selectors")]
+    #[cfg_attr(feature = "servo", ignore_malloc_size_of = "defined in selectors")]
    quirks_mode: QuirksMode,

    /// Selector maps for all of the style sheets in the stylist, after
@ -1517,7 +1517,7 @@ impl Stylist {
 /// This struct holds data which users of Stylist may want to extract
 /// from stylesheets which can be done at the same time as updating.
 #[derive(Debug, Default)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct ExtraStyleData {
    /// A list of effective font-face rules and their origin.
    #[cfg(feature = "gecko")]
@ -1783,7 +1783,7 @@ impl<'a> SelectorVisitor for StylistSelectorVisitor<'a> {
 ///
 /// FIXME(emilio): Consider renaming and splitting in `CascadeData` and
 /// `InvalidationData`? That'd make `clear_cascade_data()` clearer.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Debug)]
 struct CascadeData {
    /// Rules from stylesheets at this `CascadeData`'s origin.
@ -1808,7 +1808,7 @@ struct CascadeData {
    /// to avoid taking element snapshots when an irrelevant attribute changes.
    /// (We don't bother storing the namespace, since namespaced attributes
    /// are rare.)
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "just an array")]
+    #[cfg_attr(feature = "servo", ignore_malloc_size_of = "just an array")]
    attribute_dependencies: NonCountingBloomFilter,

    /// Whether `"style"` appears in an attribute selector.  This is not common,
@ -1828,13 +1828,13 @@ struct CascadeData {
    /// hence in our selector maps).  Used to determine when sharing styles is
    /// safe: we disallow style sharing for elements whose id matches this
    /// filter, and hence might be in one of our selector maps.
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "just an array")]
+    #[cfg_attr(feature = "servo", ignore_malloc_size_of = "just an array")]
    mapped_ids: NonCountingBloomFilter,

    /// Selectors that require explicit cache revalidation (i.e. which depend
    /// on state that is not otherwise visible to the cache, like attributes or
    /// tree-structural state like child index and pseudos).
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+    #[cfg_attr(feature = "servo", ignore_malloc_size_of = "Arc")]
    selectors_for_cache_revalidation: SelectorMap<RevalidationSelectorAndHashes>,

    /// Effective media query results cached from the last rebuild.
@ -2251,21 +2251,16 @@ impl Default for CascadeData {

 /// A rule, that wraps a style rule, but represents a single selector of the
 /// rule.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub struct Rule {
    /// The selector this struct represents. We store this and the
    /// any_{important,normal} booleans inline in the Rule to avoid
    /// pointer-chasing when gathering applicable declarations, which
    /// can ruin performance when there are a lot of rules.
-    #[cfg_attr(feature = "gecko",
-               ignore_malloc_size_of = "CssRules have primary refs, we measure there")]
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+    #[ignore_malloc_size_of = "CssRules have primary refs, we measure there"]
    pub selector: Selector<SelectorImpl>,

    /// The ancestor hashes associated with the selector.
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "No heap data")]
    pub hashes: AncestorHashes,

    /// The source order this style rule appears in. Note that we only use
@ -2277,7 +2272,7 @@ pub struct Rule {
    #[cfg_attr(feature = "gecko",
               ignore_malloc_size_of =
                   "Secondary ref. Primary ref is in StyleRule under Stylesheet.")]
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+    #[cfg_attr(feature = "servo", ignore_malloc_size_of = "Arc")]
    pub style_rule: Arc<Locked<StyleRule>>,
 }

--- a/components/style/values/animated/color.rs
+++ b/components/style/values/animated/color.rs
@ -11,7 +11,7 @@ use values::distance::{ComputeSquaredDistance, SquaredDistance};
 ///
 /// Unlike in computed values, each component value may exceed the
 /// range `[0.0, 1.0]`.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Clone, Copy, Debug, PartialEq, ToAnimatedZero)]
 pub struct RGBA {
    /// The red component.
@ -70,7 +70,7 @@ impl ComputeSquaredDistance for RGBA {
 }

 #[allow(missing_docs)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct Color {
    pub color: RGBA,
--- a/components/style/values/animated/effects.rs
+++ b/components/style/values/animated/effects.rs
@ -28,7 +28,7 @@ pub type TextShadowList = ShadowList<SimpleShadow>;
 /// An animated value for shadow lists.
 ///
 /// <https://drafts.csswg.org/css-transitions/#animtype-shadow-list>
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Clone, Debug, PartialEq)]
 pub struct ShadowList<Shadow>(Vec<Shadow>);

@ -36,7 +36,7 @@ pub struct ShadowList<Shadow>(Vec<Shadow>);
 pub type BoxShadow = GenericBoxShadow<Option<RGBA>, Length, NonNegativeLength, Length>;

 /// An animated value for the `filter` property.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Clone, Debug, PartialEq)]
 pub struct FilterList(pub Vec<Filter>);

--- a/components/style/values/computed/angle.rs
+++ b/components/style/values/computed/angle.rs
@ -14,9 +14,8 @@ use values::distance::{ComputeSquaredDistance, SquaredDistance};

 /// A computed angle.
 #[animate(fallback = "Self::animate_fallback")]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
-#[derive(Animate, Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[derive(Animate, Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 #[derive(PartialOrd, ToAnimatedZero)]
 pub enum Angle {
    /// An angle with degree unit.
--- a/components/style/values/computed/color.rs
+++ b/components/style/values/computed/color.rs
@ -14,9 +14,7 @@ use values::animated::color::{Color as AnimatedColor, RGBA as AnimatedRGBA};
 /// the current foreground color (currentcolor keyword).
 /// Conceptually, the formula is "color * (1 - p) + currentcolor * p"
 /// where p is foreground_ratio.
-#[derive(Clone, Copy, Debug)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf)]
 pub struct Color {
    /// RGBA color.
    pub color: RGBA,
--- a/components/style/values/computed/font.rs
+++ b/components/style/values/computed/font.rs
@ -11,10 +11,8 @@ use values::animated::ToAnimatedValue;
 use values::computed::NonNegativeLength;
 use values::specified::font as specified;

-#[derive(Animate, ComputeSquaredDistance, ToAnimatedZero)]
+#[derive(Animate, ComputeSquaredDistance, MallocSizeOf, ToAnimatedZero)]
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
 /// The computed value of font-size
 pub struct FontSize {
    /// The size.
@ -23,10 +21,8 @@ pub struct FontSize {
    pub keyword_info: Option<KeywordInfo>,
 }

-#[derive(Animate, ComputeSquaredDistance, ToAnimatedValue, ToAnimatedZero)]
+#[derive(Animate, ComputeSquaredDistance, MallocSizeOf, ToAnimatedValue, ToAnimatedZero)]
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
 /// Additional information for keyword-derived font sizes.
 pub struct KeywordInfo {
    /// The keyword used
--- a/components/style/values/computed/image.rs
+++ b/components/style/values/computed/image.rs
@ -51,9 +51,7 @@ pub type GradientKind = GenericGradientKind<
 >;

 /// A computed gradient line direction.
-#[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub enum LineDirection {
    /// An angle.
    Angle(Angle),
--- a/components/style/values/computed/length.rs
+++ b/components/style/values/computed/length.rs
@ -66,9 +66,7 @@ impl ToComputedValue for specified::Length {
 }

 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToAnimatedZero)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToAnimatedZero)]
 pub struct CalcLengthOrPercentage {
    #[animation(constant)]
    pub clamping_mode: AllowedNumericType,
@ -294,10 +292,8 @@ impl ToComputedValue for specified::CalcLengthOrPercentage {

 #[allow(missing_docs)]
 #[animate(fallback = "Self::animate_fallback")]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[css(derive_debug)]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, PartialEq)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, MallocSizeOf, PartialEq)]
 #[derive(ToAnimatedZero, ToCss)]
 #[distance(fallback = "Self::compute_squared_distance_fallback")]
 pub enum LengthOrPercentage {
@ -452,10 +448,8 @@ impl ToComputedValue for specified::LengthOrPercentage {

 #[allow(missing_docs)]
 #[animate(fallback = "Self::animate_fallback")]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[css(derive_debug)]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, PartialEq, ToCss)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, MallocSizeOf, PartialEq, ToCss)]
 #[distance(fallback = "Self::compute_squared_distance_fallback")]
 pub enum LengthOrPercentageOrAuto {
    Length(Length),
@ -549,7 +543,7 @@ impl ToComputedValue for specified::LengthOrPercentageOrAuto {

 #[allow(missing_docs)]
 #[animate(fallback = "Self::animate_fallback")]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[css(derive_debug)]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, PartialEq, ToCss)]
 #[distance(fallback = "Self::compute_squared_distance_fallback")]
@ -684,9 +678,8 @@ impl NonNegativeLengthOrPercentage {
 }

 /// The computed `<length>` value.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(Deserialize, HeapSizeOf, Serialize))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, PartialEq, PartialOrd)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd)]
 #[derive(ToAnimatedValue, ToAnimatedZero)]
 pub struct CSSPixelLength(CSSFloat);

@ -850,7 +843,7 @@ pub type NonNegativeLengthOrNumber = Either<NonNegativeLength, NonNegativeNumber
 /// A value suitable for a `min-width`, `min-height`, `width` or `height` property.
 /// See values/specified/length.rs for more details.
 #[allow(missing_docs)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, PartialEq)]
 #[derive(ToAnimatedZero, ToCss)]
 pub enum MozLength {
@ -900,7 +893,7 @@ impl ToComputedValue for specified::MozLength {
 /// A value suitable for a `max-width` or `max-height` property.
 /// See values/specified/length.rs for more details.
 #[allow(missing_docs)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, PartialEq, ToCss)]
 pub enum MaxLength {
    LengthOrPercentageOrNone(LengthOrPercentageOrNone),
--- a/components/style/values/computed/mod.rs
+++ b/components/style/values/computed/mod.rs
@ -397,9 +397,7 @@ impl From<GreaterThanOrEqualToOneNumber> for CSSFloat {
 }

 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, ComputeSquaredDistance, Copy, Debug, PartialEq, ToCss)]
+#[derive(Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum NumberOrPercentage {
    Percentage(Percentage),
    Number(Number),
@ -468,7 +466,7 @@ pub type LengthOrPercentageOrNumber = Either<Number, LengthOrPercentage>;
 pub type NonNegativeLengthOrPercentageOrNumber = Either<NonNegativeNumber, NonNegativeLengthOrPercentage>;

 #[allow(missing_docs)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Clone, ComputeSquaredDistance, Copy, Debug, PartialEq)]
 /// A computed cliprect for clip and image-region
 pub struct ClipRect {
@ -550,10 +548,10 @@ pub type ColorOrAuto = Either<Color, Auto>;

 /// The computed value of a CSS `url()`, resolved relative to the stylesheet URL.
 #[cfg(feature = "servo")]
-#[derive(Clone, Debug, Deserialize, HeapSizeOf, PartialEq, Serialize)]
+#[derive(Clone, Debug, Deserialize, MallocSizeOf, PartialEq, Serialize)]
 pub enum ComputedUrl {
    /// The `url()` was invalid or it wasn't specified by the user.
-    Invalid(Arc<String>),
+    Invalid(#[ignore_malloc_size_of = "Arc"] Arc<String>),
    /// The resolved `url()` relative to the stylesheet URL.
    Valid(ServoUrl),
 }
--- a/components/style/values/computed/percentage.rs
+++ b/components/style/values/computed/percentage.rs
@ -9,9 +9,8 @@ use style_traits::ToCss;
 use values::{CSSFloat, serialize_percentage};

 /// A computed percentage.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(Deserialize, HeapSizeOf, Serialize))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, Default)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, Default, MallocSizeOf)]
 #[derive(PartialEq, PartialOrd, ToAnimatedZero)]
 pub struct Percentage(pub CSSFloat);

--- a/components/style/values/computed/time.rs
+++ b/components/style/values/computed/time.rs
@ -9,9 +9,8 @@ use style_traits::ToCss;
 use values::CSSFloat;

 /// A computed `<time>` value.
-#[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 pub struct Time {
    seconds: CSSFloat,
 }
--- a/components/style/values/generics/background.rs
+++ b/components/style/values/generics/background.rs
@ -5,10 +5,8 @@
 //! Generic types for CSS values related to backgrounds.

 /// A generic value for the `background-size` property.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
-#[derive(PartialEq, ToComputedValue, ToCss)]
+#[derive(MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum BackgroundSize<LengthOrPercentageOrAuto> {
    /// `<width> <height>`
    Explicit {
--- a/components/style/values/generics/basic_shape.rs
+++ b/components/style/values/generics/basic_shape.rs
@ -18,9 +18,7 @@ pub type ClippingShape<BasicShape, Url> = ShapeSource<BasicShape, GeometryBox, U

 /// <https://drafts.fxtf.org/css-masking-1/#typedef-geometry-box>
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum GeometryBox {
    FillBox,
    StrokeBox,
@ -42,9 +40,7 @@ add_impls_for_keyword_enum!(ShapeBox);

 /// A shape source, for some reference box.
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Animate, Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum ShapeSource<BasicShape, ReferenceBox, Url> {
    #[animation(error)]
    Url(Url),
@ -60,9 +56,7 @@ pub enum ShapeSource<BasicShape, ReferenceBox, Url> {
 }

 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Debug, PartialEq)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Debug, MallocSizeOf, PartialEq)]
 #[derive(ToComputedValue, ToCss)]
 pub enum BasicShape<H, V, LengthOrPercentage> {
    Inset(InsetRect<LengthOrPercentage>),
@ -73,9 +67,7 @@ pub enum BasicShape<H, V, LengthOrPercentage> {

 /// <https://drafts.csswg.org/css-shapes/#funcdef-inset>
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Debug, PartialEq, ToComputedValue)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct InsetRect<LengthOrPercentage> {
    pub rect: Rect<LengthOrPercentage>,
    pub round: Option<BorderRadius<LengthOrPercentage>>,
@ -83,9 +75,7 @@ pub struct InsetRect<LengthOrPercentage> {

 /// <https://drafts.csswg.org/css-shapes/#funcdef-circle>
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, PartialEq, ToComputedValue)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct Circle<H, V, LengthOrPercentage> {
    pub position: Position<H, V>,
    pub radius: ShapeRadius<LengthOrPercentage>,
@ -93,9 +83,7 @@ pub struct Circle<H, V, LengthOrPercentage> {

 /// <https://drafts.csswg.org/css-shapes/#funcdef-ellipse>
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, PartialEq, ToComputedValue)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct Ellipse<H, V, LengthOrPercentage> {
    pub position: Position<H, V>,
    pub semiaxis_x: ShapeRadius<LengthOrPercentage>,
@ -104,9 +92,7 @@ pub struct Ellipse<H, V, LengthOrPercentage> {

 /// <https://drafts.csswg.org/css-shapes/#typedef-shape-radius>
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, PartialEq)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq)]
 #[derive(ToComputedValue, ToCss)]
 pub enum ShapeRadius<LengthOrPercentage> {
    Length(LengthOrPercentage),
@ -116,12 +102,10 @@ pub enum ShapeRadius<LengthOrPercentage> {
    FarthestSide,
 }

-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToComputedValue)]
 /// A generic type for representing the `polygon()` function
 ///
 /// <https://drafts.csswg.org/css-shapes/#funcdef-polygon>
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct Polygon<LengthOrPercentage> {
    /// The filling rule for a polygon.
    pub fill: FillRule,
--- a/components/style/values/generics/border.rs
+++ b/components/style/values/generics/border.rs
@ -10,9 +10,7 @@ use values::generics::rect::Rect;
 use values::generics::size::Size;

 /// A generic value for a single side of a `border-image-width` property.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum BorderImageSideWidth<LengthOrPercentage, Number> {
    /// `<length-or-percentage>`
    Length(LengthOrPercentage),
@ -23,9 +21,7 @@ pub enum BorderImageSideWidth<LengthOrPercentage, Number> {
 }

 /// A generic value for the `border-image-slice` property.
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct BorderImageSlice<NumberOrPercentage> {
    /// The offsets.
    pub offsets: Rect<NumberOrPercentage>,
@ -34,10 +30,8 @@ pub struct BorderImageSlice<NumberOrPercentage> {
 }

 /// A generic value for the `border-*-radius` longhand properties.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
-#[derive(PartialEq, ToComputedValue, ToCss)]
+#[derive(MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub struct BorderCornerRadius<L>(pub Size<L>);

 impl<L> BorderCornerRadius<L> {
@ -48,9 +42,7 @@ impl<L> BorderCornerRadius<L> {
 }

 /// A generic value for the `border-spacing` property.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf)]
 #[derive(PartialEq, ToAnimatedValue, ToComputedValue, ToCss)]
 pub struct BorderSpacing<L>(pub Size<L>);

@ -64,10 +56,8 @@ impl<L> BorderSpacing<L> {
 /// A generic value for `border-radius`, `outline-radius` and `inset()`.
 ///
 /// <https://drafts.csswg.org/css-backgrounds-3/#border-radius>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
-#[derive(PartialEq, ToComputedValue)]
+#[derive(MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct BorderRadius<LengthOrPercentage> {
    /// The top left radius.
    pub top_left: BorderCornerRadius<LengthOrPercentage>,
--- a/components/style/values/generics/box.rs
+++ b/components/style/values/generics/box.rs
@ -7,9 +7,7 @@
 use values::animated::ToAnimatedZero;

 /// A generic value for the `vertical-align` property.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, PartialEq)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq)]
 #[derive(ToComputedValue, ToCss)]
 pub enum VerticalAlign<LengthOrPercentage> {
    /// `baseline`
--- a/components/style/values/generics/effects.rs
+++ b/components/style/values/generics/effects.rs
@ -10,9 +10,7 @@ use style_traits::values::{SequenceWriter, ToCss};
 use values::specified::url::SpecifiedUrl;

 /// A generic value for a single `box-shadow`.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, Debug, PartialEq)]
+#[derive(Animate, Clone, Debug, MallocSizeOf, PartialEq)]
 #[derive(ToAnimatedValue, ToAnimatedZero)]
 pub struct BoxShadow<Color, SizeLength, BlurShapeLength, ShapeLength> {
    /// The base shadow.
@ -25,9 +23,8 @@ pub struct BoxShadow<Color, SizeLength, BlurShapeLength, ShapeLength> {
 }

 /// A generic value for a single `filter`.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(Deserialize, HeapSizeOf, Serialize))]
-#[derive(Clone, Debug, PartialEq, ToAnimatedValue, ToComputedValue, ToCss)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToAnimatedValue, ToComputedValue, ToCss)]
 pub enum Filter<Angle, Factor, Length, DropShadow> {
    /// `blur(<length>)`
    #[css(function)]
@ -68,10 +65,8 @@ pub enum Filter<Angle, Factor, Length, DropShadow> {
 ///
 /// Contrary to the canonical order from the spec, the color is serialised
 /// first, like in Gecko and Webkit.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Debug)]
-#[derive(PartialEq, ToAnimatedValue, ToAnimatedZero, ToCss)]
+#[derive(MallocSizeOf, PartialEq, ToAnimatedValue, ToAnimatedZero, ToCss)]
 pub struct SimpleShadow<Color, SizeLength, ShapeLength> {
    /// Color.
    pub color: Color,
--- a/components/style/values/generics/flex.rs
+++ b/components/style/values/generics/flex.rs
@ -7,7 +7,7 @@
 use values::computed::Percentage;

 /// A generic value for the `flex-basis` property.
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 #[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
 pub enum FlexBasis<LengthOrPercentage> {
    /// `auto`
--- a/components/style/values/generics/grid.rs
+++ b/components/style/values/generics/grid.rs
@ -17,9 +17,7 @@ use values::specified::grid::parse_line_names;
 /// A `<grid-line>` type.
 ///
 /// <https://drafts.csswg.org/css-grid/#typedef-grid-row-start-grid-line>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, Default, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, Default, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct GridLine<Integer> {
    /// Flag to check whether it's a `span` keyword.
    pub is_span: bool,
@ -145,9 +143,7 @@ add_impls_for_keyword_enum!(TrackKeyword);
 /// avoid re-implementing it for the computed type.
 ///
 /// <https://drafts.csswg.org/css-grid/#typedef-track-breadth>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub enum TrackBreadth<L> {
    /// The generic type is almost always a non-negative `<length-percentage>`
    Breadth(L),
@ -184,9 +180,7 @@ impl<L: ToCss> ToCss for TrackBreadth<L> {
 /// generic only to avoid code bloat. It only takes `<length-percentage>`
 ///
 /// <https://drafts.csswg.org/css-grid/#typedef-track-size>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 pub enum TrackSize<L> {
    /// A flexible `<track-breadth>`
    Breadth(TrackBreadth<L>),
@ -348,9 +342,7 @@ where
 /// The initial argument of the `repeat` function.
 ///
 /// <https://drafts.csswg.org/css-grid/#typedef-track-repeat>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum RepeatCount<Integer> {
    /// A positive integer. This is allowed only for `<track-repeat>` and `<fixed-repeat>`
    Number(Integer),
@ -382,9 +374,7 @@ impl Parse for RepeatCount<specified::Integer> {
 ///
 /// It can also hold `repeat()` function parameters, which expands into the respective
 /// values in its computed form.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct TrackRepeat<L, I> {
    /// The number of times for the value to be repeated (could also be `auto-fit` or `auto-fill`)
    pub count: RepeatCount<I>,
@ -465,9 +455,7 @@ impl<L: Clone> TrackRepeat<L, specified::Integer> {
 }

 /// Track list values. Can be <track-size> or <track-repeat>
-#[derive(Clone, Debug, PartialEq, ToComputedValue, ToCss)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum TrackListValue<LengthOrPercentage, Integer> {
    /// A <track-size> value.
    TrackSize(TrackSize<LengthOrPercentage>),
@ -478,9 +466,7 @@ pub enum TrackListValue<LengthOrPercentage, Integer> {
 /// The type of a `<track-list>` as determined during parsing.
 ///
 /// <https://drafts.csswg.org/css-grid/#typedef-track-list>
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub enum TrackListType {
    /// [`<auto-track-list>`](https://drafts.csswg.org/css-grid/#typedef-auto-track-list)
    ///
@ -502,9 +488,7 @@ pub enum TrackListType {
 /// A grid `<track-list>` type.
 ///
 /// <https://drafts.csswg.org/css-grid/#typedef-track-list>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 pub struct TrackList<LengthOrPercentage, Integer> {
    /// The type of this `<track-list>` (auto, explicit or general).
    ///
@ -571,9 +555,7 @@ impl<L: ToCss, I: ToCss> ToCss for TrackList<L, I> {
 ///
 /// `subgrid [ <line-names> | repeat(<positive-integer> | auto-fill, <line-names>+) ]+`
 /// Old spec: https://www.w3.org/TR/2015/WD-css-grid-1-20150917/#typedef-line-name-list
-#[derive(Clone, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, Default, MallocSizeOf, PartialEq)]
 pub struct LineNameList {
    /// The optional `<line-name-list>`
    pub names: Box<[Box<[CustomIdent]>]>,
@ -668,9 +650,7 @@ impl ToCss for LineNameList {
 /// Variants for `<grid-template-rows> | <grid-template-columns>`
 /// Subgrid deferred to Level 2 spec due to lack of implementation.
 /// But it's implemented in gecko, so we have to as well.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum GridTemplateComponent<L, I> {
    /// `none` value.
    None,
--- a/components/style/values/generics/image.rs
+++ b/components/style/values/generics/image.rs
@ -16,9 +16,7 @@ use style_traits::ToCss;
 /// An [image].
 ///
 /// [image]: https://drafts.csswg.org/css-images/#image-values
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, PartialEq, ToComputedValue)]
+#[derive(Clone, MallocSizeOf, PartialEq, ToComputedValue)]
 pub enum Image<Gradient, MozImageRect, ImageUrl> {
    /// A `<url()>` image.
    Url(ImageUrl),
@ -37,9 +35,7 @@ pub enum Image<Gradient, MozImageRect, ImageUrl> {

 /// A CSS gradient.
 /// <https://drafts.csswg.org/css-images/#gradients>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct Gradient<LineDirection, Length, LengthOrPercentage, Position, Color, Angle> {
    /// Gradients can be linear or radial.
    pub kind: GradientKind<LineDirection, Length, LengthOrPercentage, Position, Angle>,
@ -53,9 +49,7 @@ pub struct Gradient<LineDirection, Length, LengthOrPercentage, Position, Color,
    pub compat_mode: CompatMode,
 }

-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 /// Whether we used the modern notation or the compatibility `-webkit`, `-moz` prefixes.
 pub enum CompatMode {
    /// Modern syntax.
@ -67,9 +61,7 @@ pub enum CompatMode {
 }

 /// A gradient kind.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub enum GradientKind<LineDirection, Length, LengthOrPercentage, Position, Angle> {
    /// A linear gradient.
    Linear(LineDirection),
@ -78,9 +70,7 @@ pub enum GradientKind<LineDirection, Length, LengthOrPercentage, Position, Angle
 }

 /// A radial gradient's ending shape.
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum EndingShape<Length, LengthOrPercentage> {
    /// A circular gradient.
    Circle(Circle<Length>),
@ -89,9 +79,7 @@ pub enum EndingShape<Length, LengthOrPercentage> {
 }

 /// A circle shape.
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub enum Circle<Length> {
    /// A circle radius.
    Radius(Length),
@ -100,9 +88,7 @@ pub enum Circle<Length> {
 }

 /// An ellipse shape.
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum Ellipse<LengthOrPercentage> {
    /// An ellipse pair of radii.
    Radii(LengthOrPercentage, LengthOrPercentage),
@ -123,9 +109,7 @@ add_impls_for_keyword_enum!(ShapeExtent);

 /// A gradient item.
 /// <https://drafts.csswg.org/css-images-4/#color-stop-syntax>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum GradientItem<Color, LengthOrPercentage> {
    /// A color stop.
    ColorStop(ColorStop<Color, LengthOrPercentage>),
@ -135,9 +119,7 @@ pub enum GradientItem<Color, LengthOrPercentage> {

 /// A color stop.
 /// <https://drafts.csswg.org/css-images/#typedef-color-stop-list>
-#[derive(Clone, Copy, PartialEq, ToComputedValue, ToCss)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub struct ColorStop<Color, LengthOrPercentage> {
    /// The color of this stop.
    pub color: Color,
@ -148,13 +130,13 @@ pub struct ColorStop<Color, LengthOrPercentage> {
 /// Specified values for a paint worklet.
 /// <https://drafts.css-houdini.org/css-paint-api/>
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct PaintWorklet {
    /// The name the worklet was registered with.
    pub name: Atom,
    /// The arguments for the worklet.
    /// TODO: store a parsed representation of the arguments.
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
+    #[cfg_attr(feature = "servo", ignore_malloc_size_of = "Arc")]
    pub arguments: Vec<Arc<custom_properties::SpecifiedValue>>,
 }

@ -176,10 +158,8 @@ impl ToCss for PaintWorklet {
 ///
 /// `-moz-image-rect(<uri>, top, right, bottom, left);`
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[css(comma, function)]
-#[derive(Clone, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub struct MozImageRect<NumberOrPercentage, MozImageRectUrl> {
    pub url: MozImageRectUrl,
    pub top: NumberOrPercentage,
--- a/components/style/values/generics/mod.rs
+++ b/components/style/values/generics/mod.rs
@ -131,9 +131,7 @@ impl Parse for CounterStyleOrNone {
 ///
 /// For font-feature-settings, this is a tag and an integer,
 /// for font-variation-settings this is a tag and a float
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, Eq, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct FontSettingTag<T> {
    /// A four-character tag, packed into a u32 (one byte per character)
    pub tag: u32,
@ -190,9 +188,7 @@ impl<T: Parse> Parse for FontSettingTag<T> {


 /// A font settings value for font-variation-settings or font-feature-settings
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, Eq, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum FontSettings<T> {
    /// No settings (default)
    Normal,
@ -215,18 +211,15 @@ impl<T: Parse> Parse for FontSettings<T> {
 ///
 /// Do not use this type anywhere except within FontSettings
 /// because it serializes with the preceding space
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, Eq, PartialEq, ToComputedValue)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct FontSettingTagInt(pub u32);

 /// A number value to be used for font-variation-settings
 ///
 /// Do not use this type anywhere except within FontSettings
 /// because it serializes with the preceding space
-#[cfg_attr(feature = "gecko", derive(Animate, ComputeSquaredDistance, MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToComputedValue)]
+#[cfg_attr(feature = "gecko", derive(Animate, ComputeSquaredDistance))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct FontSettingTagFloat(pub f32);

 impl ToCss for FontSettingTagInt {
@ -279,15 +272,13 @@ impl ToCss for FontSettingTagFloat {
 }

 /// A wrapper of Non-negative values.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(Deserialize, HeapSizeOf, Serialize))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf)]
 #[derive(PartialEq, PartialOrd, ToAnimatedZero, ToComputedValue, ToCss)]
 pub struct NonNegative<T>(pub T);

 /// A wrapper of greater-than-or-equal-to-one values.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(Deserialize, HeapSizeOf, Serialize))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf)]
 #[derive(PartialEq, PartialOrd, ToAnimatedZero, ToComputedValue, ToCss)]
 pub struct GreaterThanOrEqualToOne<T>(pub T);
--- a/components/style/values/generics/position.rs
+++ b/components/style/values/generics/position.rs
@ -6,10 +6,8 @@
 //! [`position`](https://drafts.csswg.org/css-backgrounds-3/#position)

 /// A generic type for representing a CSS [position](https://drafts.csswg.org/css-values/#position).
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
-#[derive(PartialEq, ToAnimatedZero, ToComputedValue)]
+#[derive(MallocSizeOf, PartialEq, ToAnimatedZero, ToComputedValue)]
 pub struct Position<H, V> {
    /// The horizontal component of position.
    pub horizontal: H,
--- a/components/style/values/generics/rect.rs
+++ b/components/style/values/generics/rect.rs
@ -11,10 +11,8 @@ use style_traits::{ToCss, ParseError};

 /// A CSS value made of four components, where its `ToCss` impl will try to
 /// serialize as few components as possible, like for example in `border-width`.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
-#[derive(PartialEq, ToComputedValue)]
+#[derive(MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct Rect<T>(pub T, pub T, pub T, pub T);

 impl<T> Rect<T> {
--- a/components/style/values/generics/size.rs
+++ b/components/style/values/generics/size.rs
@ -13,10 +13,8 @@ use values::animated::ToAnimatedValue;

 /// A generic size, for `border-*-radius` longhand properties, or
 /// `border-spacing`.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
-#[derive(PartialEq, ToComputedValue)]
+#[derive(MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct Size<L>(pub Size2D<L>);

 impl<L> Size<L> {
--- a/components/style/values/generics/svg.rs
+++ b/components/style/values/generics/svg.rs
@ -16,9 +16,7 @@ use values::distance::{ComputeSquaredDistance, SquaredDistance};
 /// An SVG paint value
 ///
 /// <https://www.w3.org/TR/SVG2/painting.html#SpecifyingPaint>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Debug, PartialEq)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Debug, MallocSizeOf, PartialEq)]
 #[derive(ToAnimatedValue, ToComputedValue, ToCss)]
 pub struct SVGPaint<ColorType, UrlPaintServer> {
    /// The paint source
@ -32,9 +30,7 @@ pub struct SVGPaint<ColorType, UrlPaintServer> {
 /// Whereas the spec only allows PaintServer
 /// to have a fallback, Gecko lets the context
 /// properties have a fallback as well.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Debug, PartialEq)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Debug, MallocSizeOf, PartialEq)]
 #[derive(ToAnimatedValue, ToAnimatedZero, ToComputedValue, ToCss)]
 pub enum SVGPaintKind<ColorType, UrlPaintServer> {
    /// `none`
@ -111,9 +107,7 @@ impl<ColorType: Parse, UrlPaintServer: Parse> Parse for SVGPaint<ColorType, UrlP

 /// A value of <length> | <percentage> | <number> for svg which allow unitless length.
 /// <https://www.w3.org/TR/SVG11/painting.html#StrokeProperties>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToAnimatedValue)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToAnimatedValue)]
 #[derive(ToAnimatedZero, ToComputedValue, ToCss)]
 pub enum SvgLengthOrPercentageOrNumber<LengthOrPercentage, Number> {
    /// <length> | <percentage>
@ -194,9 +188,7 @@ impl <LengthOrPercentageType: Parse, NumberType: Parse> Parse for
 }

 /// An SVG length value supports `context-value` in addition to length.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, ComputeSquaredDistance, Copy, Debug, PartialEq)]
+#[derive(Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq)]
 #[derive(ToAnimatedValue, ToAnimatedZero)]
 #[derive(ToComputedValue, ToCss)]
 pub enum SVGLength<LengthType> {
@ -207,9 +199,8 @@ pub enum SVGLength<LengthType> {
 }

 /// Generic value for stroke-dasharray.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, ComputeSquaredDistance, Debug, PartialEq, ToAnimatedValue, ToComputedValue)]
+#[derive(Clone, ComputeSquaredDistance, Debug, MallocSizeOf, PartialEq, ToAnimatedValue,
+         ToComputedValue)]
 pub enum SVGStrokeDashArray<LengthType> {
    /// `[ <length> | <percentage> | <number> ]#`
    Values(Vec<LengthType>),
@ -242,9 +233,7 @@ impl<LengthType> ToCss for SVGStrokeDashArray<LengthType> where LengthType: ToCs

 /// An SVG opacity value accepts `context-{fill,stroke}-opacity` in
 /// addition to opacity value.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, ComputeSquaredDistance, Copy, Debug)]
+#[derive(Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf)]
 #[derive(PartialEq, ToAnimatedZero, ToComputedValue, ToCss)]
 pub enum SVGOpacity<OpacityType> {
    /// `<opacity-value>`
--- a/components/style/values/generics/text.rs
+++ b/components/style/values/generics/text.rs
@ -12,9 +12,7 @@ use values::animated::{Animate, Procedure, ToAnimatedZero};
 use values::distance::{ComputeSquaredDistance, SquaredDistance};

 /// A generic value for the `initial-letter` property.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum InitialLetter<Number, Integer> {
    /// `normal`
    Normal,
@ -31,9 +29,7 @@ impl<N, I> InitialLetter<N, I> {
 }

 /// A generic spacing value for the `letter-spacing` and `word-spacing` properties.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum Spacing<Value> {
    /// `normal`
    Normal,
@ -111,10 +107,8 @@ where
 }

 /// A generic value for the `line-height` property.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
-#[derive(PartialEq, ToAnimatedValue, ToCss)]
+#[derive(MallocSizeOf, PartialEq, ToAnimatedValue, ToCss)]
 pub enum LineHeight<Number, LengthOrPercentage> {
    /// `normal`
    Normal,
--- a/components/style/values/generics/transform.rs
+++ b/components/style/values/generics/transform.rs
@ -10,9 +10,7 @@ use values::CSSFloat;

 /// A generic 2D transformation matrix.
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 #[css(comma, function)]
 pub struct Matrix<T, U = T> {
    pub a: T,
@ -24,10 +22,8 @@ pub struct Matrix<T, U = T> {
 }

 /// A generic transform origin.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
-#[derive(PartialEq, ToAnimatedZero, ToComputedValue, ToCss)]
+#[derive(MallocSizeOf, PartialEq, ToAnimatedZero, ToComputedValue, ToCss)]
 pub struct TransformOrigin<H, V, Depth> {
    /// The horizontal origin.
    pub horizontal: H,
@ -40,9 +36,7 @@ pub struct TransformOrigin<H, V, Depth> {
 /// A generic timing function.
 ///
 /// <https://drafts.csswg.org/css-timing-1/#single-timing-function-production>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub enum TimingFunction<Integer, Number> {
    /// `linear | ease | ease-in | ease-out | ease-in-out`
    Keyword(TimingKeyword),
--- a/components/style/values/mod.rs
+++ b/components/style/values/mod.rs
@ -50,7 +50,7 @@ pub fn serialize_dimension<W>(value: CSSFloat, unit: &str, dest: &mut W)
 }

 /// Convenience void type to disable some properties and values through types.
-#[cfg_attr(feature = "servo", derive(Deserialize, HeapSizeOf, Serialize))]
+#[cfg_attr(feature = "servo", derive(Deserialize, MallocSizeOf, Serialize))]
 #[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
 pub enum Impossible {}

@ -64,9 +64,7 @@ impl Parse for Impossible {
 }

 /// A struct representing one of two kinds of values.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, MallocSizeOf)]
 #[derive(PartialEq, ToAnimatedValue, ToAnimatedZero, ToComputedValue, ToCss)]
 pub enum Either<A, B> {
    /// The first value.
@ -96,9 +94,7 @@ impl<A: Parse, B: Parse> Parse for Either<A, B> {
 }

 /// <https://drafts.csswg.org/css-values-4/#custom-idents>
-#[derive(Clone, Debug, Eq, Hash, PartialEq, ToComputedValue)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct CustomIdent(pub Atom);

 impl CustomIdent {
@ -127,9 +123,7 @@ impl ToCss for CustomIdent {
 }

 /// <https://drafts.csswg.org/css-animations/#typedef-keyframes-name>
-#[derive(Clone, Debug, ToComputedValue)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf, ToComputedValue)]
 pub enum KeyframesName {
    /// <custom-ident>
    Ident(CustomIdent),
--- a/components/style/values/specified/align.rs
+++ b/components/style/values/specified/align.rs
@ -115,9 +115,8 @@ const ALIGN_ALL_SHIFT: u32 = structs::NS_STYLE_ALIGN_ALL_SHIFT;
 ///
 /// The 16-bit field stores the primary value in its lower 8 bits, and the optional fallback value
 /// in its upper 8 bits.  This matches the representation of these properties in Gecko.
-#[derive(Clone, Copy, Debug, Eq, PartialEq, ToComputedValue)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 pub struct AlignJustifyContent(u16);

 impl AlignJustifyContent {
--- a/components/style/values/specified/angle.rs
+++ b/components/style/values/specified/angle.rs
@ -19,9 +19,8 @@ use values::specified::calc::CalcNode;
 /// Computed angles are essentially same as specified ones except for `calc()`
 /// value serialization. Therefore we are storing a computed angle inside
 /// to hold the actual value and its unit.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub struct Angle {
    value: ComputedAngle,
    was_calc: bool,
--- a/components/style/values/specified/border.rs
+++ b/components/style/values/specified/border.rs
@ -19,9 +19,7 @@ use values::specified::{AllowQuirks, Number, NumberOrPercentage};
 use values::specified::length::{Length, LengthOrPercentage, NonNegativeLength};

 /// A specified value for a single side of the `border-width` property.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum BorderSideWidth {
    /// `thin`
    Thin,
--- a/components/style/values/specified/calc.rs
+++ b/components/style/values/specified/calc.rs
@ -63,9 +63,7 @@ pub enum CalcUnit {
 }

 /// A struct to hold a simplified `<length>` or `<percentage>` expression.
-#[derive(Clone, Copy, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, Default, MallocSizeOf, PartialEq)]
 #[allow(missing_docs)]
 pub struct CalcLengthOrPercentage {
    pub clamping_mode: AllowedNumericType,
--- a/components/style/values/specified/color.rs
+++ b/components/style/values/specified/color.rs
@ -18,9 +18,7 @@ use super::AllowQuirks;
 use values::computed::{Color as ComputedColor, Context, ToComputedValue};

 /// Specified color value
-#[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 pub enum Color {
    /// The 'currentColor' keyword
    CurrentColor,
@ -336,9 +334,7 @@ impl ToComputedValue for Color {

 /// Specified color value, but resolved to just RGBA for computed value
 /// with value from color property at the same context.
-#[derive(Clone, Debug, PartialEq, ToCss)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub struct RGBAColor(pub Color);


--- a/components/style/values/specified/effects.rs
+++ b/components/style/values/specified/effects.rs
@ -35,9 +35,7 @@ pub type Filter = GenericFilter<Angle, Factor, NonNegativeLength, SimpleShadow>;
 pub type Filter = GenericFilter<Angle, Factor, NonNegativeLength, Impossible>;

 /// A value for the `<factor>` parts in `Filter`.
-#[derive(Clone, Debug, PartialEq, ToCss)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub struct Factor(NumberOrPercentage);

 impl Factor {
--- a/components/style/values/specified/font.rs
+++ b/components/style/values/specified/font.rs
@ -15,9 +15,7 @@ use values::computed::{font as computed, Context, NonNegativeLength, ToComputedV
 use values::specified::{LengthOrPercentage, NoCalcLength};
 use values::specified::length::FontBaseSize;

-#[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 /// A specified font-size value
 pub enum FontSize {
    /// A length; e.g. 10px.
@ -60,10 +58,8 @@ impl From<LengthOrPercentage> for FontSize {
 }

 /// CSS font keywords
-#[derive(Animate, ComputeSquaredDistance, ToAnimatedValue, ToAnimatedZero)]
+#[derive(Animate, ComputeSquaredDistance, MallocSizeOf, ToAnimatedValue, ToAnimatedZero)]
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
 #[allow(missing_docs)]
 pub enum KeywordSize {
    XXSmall = 1, // This is to enable the NonZero optimization
--- a/components/style/values/specified/grid.rs
+++ b/components/style/values/specified/grid.rs
@ -90,7 +90,7 @@ pub fn parse_line_names<'i, 't>(input: &mut Parser<'i, 't>) -> Result<Box<[Custo
 ///
 /// <https://drafts.csswg.org/css-grid/#typedef-track-repeat>
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 enum RepeatType {
    /// [`<auto-repeat>`](https://drafts.csswg.org/css-grid/#typedef-auto-repeat)
    Auto,
--- a/components/style/values/specified/image.rs
+++ b/components/style/values/specified/image.rs
@ -85,9 +85,7 @@ pub type GradientKind = GenericGradientKind<
 >;

 /// A specified gradient line direction.
-#[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 pub enum LineDirection {
    /// An angular direction.
    Angle(Angle),
--- a/components/style/values/specified/length.rs
+++ b/components/style/values/specified/length.rs
@ -52,9 +52,7 @@ pub fn au_to_int_px(au: f32) -> i32 {
    (au / AU_PER_PX).round() as i32
 }

-#[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 /// A font relative length.
 pub enum FontRelativeLength {
    /// A "em" value: https://drafts.csswg.org/css-values/#em
@ -208,9 +206,7 @@ impl FontRelativeLength {
    }
 }

-#[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 /// A viewport-relative length.
 ///
 /// <https://drafts.csswg.org/css-values/#viewport-relative-lengths>
@ -259,9 +255,7 @@ impl ViewportPercentageLength {
 }

 /// HTML5 "character width", as defined in HTML5 § 14.5.4.
-#[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub struct CharacterWidth(pub i32);

 impl CharacterWidth {
@ -279,9 +273,7 @@ impl CharacterWidth {
 }

 /// Represents an absolute length with its unit
-#[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub enum AbsoluteLength {
    /// An absolute length in pixels (px)
    Px(CSSFloat),
@ -441,9 +433,7 @@ impl Mul<CSSFloat> for PhysicalLength {
 /// A `<length>` without taking `calc` expressions into account
 ///
 /// <https://drafts.csswg.org/css-values/#lengths>
-#[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub enum NoCalcLength {
    /// An absolute length
    ///
@ -582,9 +572,7 @@ impl NoCalcLength {
 /// This is commonly used for the `<length>` values.
 ///
 /// <https://drafts.csswg.org/css-values/#lengths>
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum Length {
    /// The internal length type that cannot parse `calc`
    NoCalc(NoCalcLength),
@ -798,9 +786,7 @@ pub type NonNegativeLengthOrNumber = Either<NonNegativeLength, NonNegativeNumber

 /// A length or a percentage value.
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum LengthOrPercentage {
    Length(NoCalcLength),
    Percentage(computed::Percentage),
@ -970,9 +956,7 @@ impl LengthOrPercentage {

 /// Either a `<length>`, a `<percentage>`, or the `auto` keyword.
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum LengthOrPercentageOrAuto {
    Length(NoCalcLength),
    Percentage(computed::Percentage),
@ -1088,9 +1072,7 @@ impl LengthOrPercentageOrAuto {
 }

 /// Either a `<length>`, a `<percentage>`, or the `none` keyword.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 #[allow(missing_docs)]
 pub enum LengthOrPercentageOrNone {
    Length(NoCalcLength),
@ -1238,9 +1220,7 @@ impl LengthOrNumber {
 /// Unlike `max-width` or `max-height` properties, a MozLength can be
 /// `auto`, and cannot be `none`.
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum MozLength {
    LengthOrPercentageOrAuto(LengthOrPercentageOrAuto),
    ExtremumLength(ExtremumLength),
@ -1265,9 +1245,7 @@ impl MozLength {

 /// A value suitable for a `max-width` or `max-height` property.
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum MaxLength {
    LengthOrPercentageOrNone(LengthOrPercentageOrNone),
    ExtremumLength(ExtremumLength),
--- a/components/style/values/specified/mod.rs
+++ b/components/style/values/specified/mod.rs
@ -176,9 +176,7 @@ impl BorderStyle {
    }
 }

-#[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd)]
 #[allow(missing_docs)]
 pub struct Number {
    /// The numeric value itself.
@ -294,9 +292,7 @@ impl Parse for GreaterThanOrEqualToOneNumber {
 ///
 /// FIXME(emilio): Should probably use Either.
 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum NumberOrPercentage {
    Percentage(Percentage),
    Number(Number),
@ -330,9 +326,7 @@ impl Parse for NumberOrPercentage {
 }

 #[allow(missing_docs)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, PartialOrd, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd, ToCss)]
 pub struct Opacity(Number);


@ -366,9 +360,7 @@ impl ToComputedValue for Opacity {
 /// An specified `<integer>`, optionally coming from a `calc()` expression.
 ///
 /// <https://drafts.csswg.org/css-values/#integers>
-#[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd)]
 pub struct Integer {
    value: CSSInteger,
    was_calc: bool,
@ -521,9 +513,7 @@ pub type LengthOrPercentageOrNumber = Either<Number, LengthOrPercentage>;
 /// NonNegativeLengthOrPercentage | NonNegativeNumber
 pub type NonNegativeLengthOrPercentageOrNumber = Either<NonNegativeNumber, NonNegativeLengthOrPercentage>;

-#[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 /// rect(<top>, <left>, <bottom>, <right>) used by clip and image-region
 pub struct ClipRect {
    /// <top> (<length> | <auto>)
@ -693,9 +683,7 @@ pub type NamespaceId = ();
 /// An attr(...) rule
 ///
 /// `[namespace? `|`]? ident`
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, Eq, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct Attr {
    /// Optional namespace
    pub namespace: Option<(Namespace, NamespaceId)>,
--- a/components/style/values/specified/percentage.rs
+++ b/components/style/values/specified/percentage.rs
@ -16,9 +16,7 @@ use values::computed::percentage::Percentage as ComputedPercentage;
 use values::specified::calc::CalcNode;

 /// A percentage value.
-#[derive(Clone, Copy, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, Default, MallocSizeOf, PartialEq)]
 pub struct Percentage {
    /// The percentage value as a float.
    ///
--- a/components/style/values/specified/position.rs
+++ b/components/style/values/specified/position.rs
@ -27,9 +27,7 @@ pub type HorizontalPosition = PositionComponent<X>;
 pub type VerticalPosition = PositionComponent<Y>;

 /// The specified value of a component of a CSS `<position>`.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum PositionComponent<S> {
    /// `center`
    Center,
--- a/components/style/values/specified/time.rs
+++ b/components/style/values/specified/time.rs
@ -16,9 +16,7 @@ use values::computed::time::Time as ComputedTime;
 use values::specified::calc::CalcNode;

 /// A time value according to CSS-VALUES § 6.2.
-#[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub struct Time {
    seconds: CSSFloat,
    unit: TimeUnit,
@ -26,9 +24,7 @@ pub struct Time {
 }

 /// A time unit.
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq)]
 pub enum TimeUnit {
    /// `s`
    Second,
--- a/components/style/values/specified/transform.rs
+++ b/components/style/values/specified/transform.rs
@ -21,9 +21,7 @@ use values::specified::position::{Side, X, Y};
 pub type TransformOrigin = GenericTransformOrigin<OriginComponent<X>, OriginComponent<Y>, Length>;

 /// The specified value of a component of a CSS `<transform-origin>`.
-#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum OriginComponent<S> {
    /// `center`
    Center,