diff --git a/components/style/gecko/media_queries.rs b/components/style/gecko/media_queries.rs
index 954463ae91d..625802eecf6 100644
--- a/components/style/gecko/media_queries.rs
+++ b/components/style/gecko/media_queries.rs
@@ -263,13 +263,15 @@ impl PartialEq for Expression {
 
 /// A resolution.
 #[derive(Clone, Debug, PartialEq, ToCss)]
-#[css(dimension)]
 pub enum Resolution {
     /// Dots per inch.
+    #[css(dimension)]
     Dpi(CSSFloat),
     /// Dots per pixel.
+    #[css(dimension)]
     Dppx(CSSFloat),
     /// Dots per centimeter.
+    #[css(dimension)]
     Dpcm(CSSFloat),
 }
 
diff --git a/components/style/gecko/values.rs b/components/style/gecko/values.rs
index 4f1b3cbb851..fc5d75bbe4b 100644
--- a/components/style/gecko/values.rs
+++ b/components/style/gecko/values.rs
@@ -214,7 +214,7 @@ impl<L: GeckoStyleCoordConvertible> GeckoStyleCoordConvertible for TrackBreadth<
     fn to_gecko_style_coord<T: CoordDataMut>(&self, coord: &mut T) {
         match *self {
             TrackBreadth::Breadth(ref lop) => lop.to_gecko_style_coord(coord),
-            TrackBreadth::Flex(fr) => coord.set_value(CoordDataValue::FlexFraction(fr)),
+            TrackBreadth::Fr(fr) => coord.set_value(CoordDataValue::FlexFraction(fr)),
             TrackBreadth::Keyword(TrackKeyword::Auto) => coord.set_value(CoordDataValue::Auto),
             TrackBreadth::Keyword(TrackKeyword::MinContent) =>
                 coord.set_value(CoordDataValue::Enumerated(StyleGridTrackBreadth::MinContent as u32)),
@@ -235,7 +235,7 @@ impl<L: GeckoStyleCoordConvertible> GeckoStyleCoordConvertible for TrackBreadth<
                         None
                     }
                 },
-                CoordDataValue::FlexFraction(fr) => Some(TrackBreadth::Flex(fr)),
+                CoordDataValue::FlexFraction(fr) => Some(TrackBreadth::Fr(fr)),
                 CoordDataValue::Auto => Some(TrackBreadth::Keyword(TrackKeyword::Auto)),
                 _ => L::from_gecko_style_coord(coord).map(TrackBreadth::Breadth),
             }
diff --git a/components/style/values/computed/angle.rs b/components/style/values/computed/angle.rs
index 1896a530d5a..7cc10e97c4d 100644
--- a/components/style/values/computed/angle.rs
+++ b/components/style/values/computed/angle.rs
@@ -16,15 +16,18 @@ use values::distance::{ComputeSquaredDistance, SquaredDistance};
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 #[derive(Animate, Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
 #[derive(PartialOrd, ToAnimatedZero)]
-#[css(dimension)]
 pub enum Angle {
     /// An angle with degree unit.
+    #[css(dimension)]
     Deg(CSSFloat),
     /// An angle with gradian unit.
+    #[css(dimension)]
     Grad(CSSFloat),
     /// An angle with radian unit.
+    #[css(dimension)]
     Rad(CSSFloat),
     /// An angle with turn unit.
+    #[css(dimension)]
     Turn(CSSFloat),
 }
 
diff --git a/components/style/values/generics/grid.rs b/components/style/values/generics/grid.rs
index db2e4721075..bd0dc82507f 100644
--- a/components/style/values/generics/grid.rs
+++ b/components/style/values/generics/grid.rs
@@ -9,7 +9,7 @@ use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use std::{fmt, mem, usize};
 use style_traits::{ToCss, ParseError, StyleParseErrorKind};
-use values::{CSSFloat, CustomIdent, serialize_dimension};
+use values::{CSSFloat, CustomIdent};
 use values::computed::{Context, ToComputedValue};
 use values::specified;
 use values::specified::grid::parse_line_names;
@@ -143,12 +143,13 @@ add_impls_for_keyword_enum!(TrackKeyword);
 /// avoid re-implementing it for the computed type.
 ///
 /// <https://drafts.csswg.org/css-grid/#typedef-track-breadth>
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum TrackBreadth<L> {
     /// The generic type is almost always a non-negative `<length-percentage>`
     Breadth(L),
     /// A flex fraction specified in `fr` units.
-    Flex(CSSFloat),
+    #[css(dimension)]
+    Fr(CSSFloat),
     /// One of the track-sizing keywords (`auto`, `min-content`, `max-content`)
     Keyword(TrackKeyword),
 }
@@ -166,16 +167,6 @@ impl<L> TrackBreadth<L> {
     }
 }
 
-impl<L: ToCss> ToCss for TrackBreadth<L> {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        match *self {
-            TrackBreadth::Breadth(ref lop) => lop.to_css(dest),
-            TrackBreadth::Flex(ref value) => serialize_dimension(*value, "fr", dest),
-            TrackBreadth::Keyword(ref k) => k.to_css(dest),
-        }
-    }
-}
-
 /// A `<track-size>` type for explicit grid track sizing. Like `<track-breadth>`, this is
 /// generic only to avoid code bloat. It only takes `<length-percentage>`
 ///
@@ -212,7 +203,7 @@ impl<L> TrackSize<L> {
                 }
 
                 match *breadth_1 {
-                    TrackBreadth::Flex(_) => false,     // should be <inflexible-breadth> at this point
+                    TrackBreadth::Fr(_) => false,     // should be <inflexible-breadth> at this point
                     _ => breadth_2.is_fixed(),
                 }
             },
@@ -242,7 +233,7 @@ impl<L: ToCss> ToCss for TrackSize<L> {
                 // According to gecko minmax(auto, <flex>) is equivalent to <flex>,
                 // and both are serialized as <flex>.
                 if let TrackBreadth::Keyword(TrackKeyword::Auto) = *min {
-                    if let TrackBreadth::Flex(_) = *max {
+                    if let TrackBreadth::Fr(_) = *max {
                         return max.to_css(dest);
                     }
                 }
@@ -268,7 +259,7 @@ impl<L: ToComputedValue> ToComputedValue for TrackSize<L> {
     #[inline]
     fn to_computed_value(&self, context: &Context) -> Self::ComputedValue {
         match *self {
-            TrackSize::Breadth(TrackBreadth::Flex(ref f)) => {
+            TrackSize::Breadth(TrackBreadth::Fr(ref f)) => {
                 // <flex> outside `minmax()` expands to `mimmax(auto, <flex>)`
                 // https://drafts.csswg.org/css-grid/#valdef-grid-template-columns-flex
                 // FIXME(nox): This sounds false, the spec just says that <flex>
@@ -276,7 +267,7 @@ impl<L: ToComputedValue> ToComputedValue for TrackSize<L> {
                 // into `minmax` at computed value time.
                 TrackSize::Minmax(
                     TrackBreadth::Keyword(TrackKeyword::Auto),
-                    TrackBreadth::Flex(f.to_computed_value(context)),
+                    TrackBreadth::Fr(f.to_computed_value(context)),
                 )
             },
             TrackSize::Breadth(ref b) => {
diff --git a/components/style/values/mod.rs b/components/style/values/mod.rs
index 7a690662acc..0aa1ae4ccf3 100644
--- a/components/style/values/mod.rs
+++ b/components/style/values/mod.rs
@@ -41,14 +41,6 @@ pub fn serialize_percentage<W>(value: CSSFloat, dest: &mut W)
     dest.write_str("%")
 }
 
-/// Serialize a value with given unit into dest.
-pub fn serialize_dimension<W>(value: CSSFloat, unit: &str, dest: &mut W)
-    -> fmt::Result where W: fmt::Write
-{
-    value.to_css(dest)?;
-    dest.write_str(unit)
-}
-
 /// Convenience void type to disable some properties and values through types.
 #[cfg_attr(feature = "servo", derive(Deserialize, MallocSizeOf, Serialize))]
 #[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
diff --git a/components/style/values/specified/grid.rs b/components/style/values/specified/grid.rs
index b951082aea9..f2b8453c46c 100644
--- a/components/style/values/specified/grid.rs
+++ b/components/style/values/specified/grid.rs
@@ -33,7 +33,7 @@ impl Parse for TrackBreadth<LengthOrPercentage> {
         }
 
         if let Ok(f) = input.try(parse_flex) {
-            return Ok(TrackBreadth::Flex(f))
+            return Ok(TrackBreadth::Fr(f))
         }
 
         TrackKeyword::parse(input).map(TrackBreadth::Keyword)
diff --git a/components/style/values/specified/length.rs b/components/style/values/specified/length.rs
index 0f677e27838..19eeb33bbcd 100644
--- a/components/style/values/specified/length.rs
+++ b/components/style/values/specified/length.rs
@@ -53,15 +53,18 @@ pub fn au_to_int_px(au: f32) -> i32 {
 
 /// A font relative length.
 #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
-#[css(dimension)]
 pub enum FontRelativeLength {
     /// A "em" value: https://drafts.csswg.org/css-values/#em
+    #[css(dimension)]
     Em(CSSFloat),
     /// A "ex" value: https://drafts.csswg.org/css-values/#ex
+    #[css(dimension)]
     Ex(CSSFloat),
     /// A "ch" value: https://drafts.csswg.org/css-values/#ch
+    #[css(dimension)]
     Ch(CSSFloat),
     /// A "rem" value: https://drafts.csswg.org/css-values/#rem
+    #[css(dimension)]
     Rem(CSSFloat)
 }
 
@@ -197,15 +200,18 @@ impl FontRelativeLength {
 ///
 /// <https://drafts.csswg.org/css-values/#viewport-relative-lengths>
 #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
-#[css(dimension)]
 pub enum ViewportPercentageLength {
     /// A vw unit: https://drafts.csswg.org/css-values/#vw
+    #[css(dimension)]
     Vw(CSSFloat),
     /// A vh unit: https://drafts.csswg.org/css-values/#vh
+    #[css(dimension)]
     Vh(CSSFloat),
     /// <https://drafts.csswg.org/css-values/#vmin>
+    #[css(dimension)]
     Vmin(CSSFloat),
     /// <https://drafts.csswg.org/css-values/#vmax>
+    #[css(dimension)]
     Vmax(CSSFloat)
 }
 
@@ -251,21 +257,27 @@ impl CharacterWidth {
 
 /// Represents an absolute length with its unit
 #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
-#[css(dimension)]
 pub enum AbsoluteLength {
     /// An absolute length in pixels (px)
+    #[css(dimension)]
     Px(CSSFloat),
     /// An absolute length in inches (in)
+    #[css(dimension)]
     In(CSSFloat),
     /// An absolute length in centimeters (cm)
+    #[css(dimension)]
     Cm(CSSFloat),
     /// An absolute length in millimeters (mm)
+    #[css(dimension)]
     Mm(CSSFloat),
     /// An absolute length in quarter-millimeters (q)
+    #[css(dimension)]
     Q(CSSFloat),
     /// An absolute length in points (pt)
+    #[css(dimension)]
     Pt(CSSFloat),
     /// An absolute length in pica (pc)
+    #[css(dimension)]
     Pc(CSSFloat),
 }
 
@@ -348,11 +360,13 @@ impl Add<AbsoluteLength> for AbsoluteLength {
 }
 
 /// Represents a physical length based on DPI.
+///
+/// FIXME(emilio): Unship (https://bugzilla.mozilla.org/show_bug.cgi?id=1416564)
 #[derive(Clone, Copy, Debug, PartialEq, ToCss)]
 #[derive(MallocSizeOf)]
-#[css(dimension)]
 pub enum PhysicalLength {
     /// A physical length in millimetres.
+    #[css(dimension)]
     Mozmm(CSSFloat),
 }
 
diff --git a/components/style_derive/to_css.rs b/components/style_derive/to_css.rs
index fa545b00211..59cc4f4236b 100644
--- a/components/style_derive/to_css.rs
+++ b/components/style_derive/to_css.rs
@@ -20,7 +20,7 @@ pub fn derive(input: DeriveInput) -> Tokens {
         let variant_attrs = cg::parse_variant_attrs::<CssVariantAttrs>(variant);
         let separator = if variant_attrs.comma { ", " } else { " " };
 
-        if input_attrs.dimension {
+        if variant_attrs.dimension {
             assert_eq!(bindings.len(), 1);
             assert!(!variant_attrs.function, "That makes no sense");
         }
@@ -58,7 +58,7 @@ pub fn derive(input: DeriveInput) -> Tokens {
             }
         };
 
-        if input_attrs.dimension {
+        if variant_attrs.dimension {
             // FIXME(emilio): Remove when bug 1416564 lands.
             if identifier == "-mozmm" {
                 identifier = "mozmm".into();
@@ -112,7 +112,6 @@ pub fn derive(input: DeriveInput) -> Tokens {
 struct CssInputAttrs {
     derive_debug: bool,
     function: bool,
-    dimension: bool,
     comma: bool,
 }
 
@@ -122,6 +121,7 @@ struct CssVariantAttrs {
     function: bool,
     iterable: bool,
     comma: bool,
+    dimension: bool,
 }
 
 /// Transforms "FooBar" to "foo-bar".