style: Use rust lengths for row-gap / column-gap.

Differential Revision: https://phabricator.services.mozilla.com/D26915

components/style/values/computed/length.rs

@@ -10,12 +10,13 @@ use crate::values::computed::NonNegativeNumber;
 use crate::values::distance::{ComputeSquaredDistance, SquaredDistance};
 use crate::values::generics::length as generics;
 use crate::values::generics::length::{
-    GenericLengthOrNumber, MaxSize as GenericMaxSize, Size as GenericSize,
+    GenericLengthPercentageOrNormal, GenericLengthOrNumber,
+    GenericMaxSize, GenericSize,
 };
 use crate::values::generics::NonNegative;
 use crate::values::specified::length::ViewportPercentageLength;
 use crate::values::specified::length::{AbsoluteLength, FontBaseSize, FontRelativeLength};
-use crate::values::{specified, CSSFloat, Either, Normal};
+use crate::values::{specified, CSSFloat};
 use crate::Zero;
 use app_units::Au;
 use ordered_float::NotNan;
@@ -782,7 +783,7 @@ impl From<NonNegativeLength> for Au {
 }
 
 /// Either a computed NonNegativeLengthPercentage or the `normal` keyword.
-pub type NonNegativeLengthPercentageOrNormal = Either<NonNegativeLengthPercentage, Normal>;
+pub type NonNegativeLengthPercentageOrNormal = GenericLengthPercentageOrNormal<NonNegativeLengthPercentage>;
 
 /// Either a non-negative `<length>` or a `<number>`.
 pub type NonNegativeLengthOrNumber = GenericLengthOrNumber<NonNegativeLength, NonNegativeNumber>;

components/style/values/generics/length.rs

@@ -219,3 +219,38 @@ impl<L, N: Zero> Zero for LengthOrNumber<L, N> {
         }
     }
 }
+
+/// A generic `<length-percentage>` | normal` value.
+#[derive(
+    Animate,
+    Clone,
+    ComputeSquaredDistance,
+    Copy,
+    Debug,
+    MallocSizeOf,
+    Parse,
+    PartialEq,
+    SpecifiedValueInfo,
+    ToAnimatedValue,
+    ToAnimatedZero,
+    ToComputedValue,
+    ToCss,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[repr(C, u8)]
+#[allow(missing_docs)]
+pub enum GenericLengthPercentageOrNormal<LengthPercent> {
+    LengthPercentage(LengthPercent),
+    Normal,
+}
+
+pub use self::GenericLengthPercentageOrNormal as LengthPercentageOrNormal;
+
+impl<LengthPercent> LengthPercentageOrNormal<LengthPercent> {
+    /// Returns the normal value.
+    #[inline]
+    pub fn normal() -> Self {
+        LengthPercentageOrNormal::Normal
+    }
+}

components/style/values/mod.rs

@@ -39,7 +39,6 @@ pub type CSSInteger = i32;
 
 define_keyword_type!(None_, "none");
 define_keyword_type!(Auto, "auto");
-define_keyword_type!(Normal, "normal");
 
 /// Serialize an identifier which is represented as an atom.
 #[cfg(feature = "gecko")]

components/style/values/specified/length.rs

@@ -13,12 +13,13 @@ use crate::properties::computed_value_flags::ComputedValueFlags;
 use crate::values::computed::{self, CSSPixelLength, Context};
 use crate::values::generics::length as generics;
 use crate::values::generics::length::{
-    GenericLengthOrNumber, MaxSize as GenericMaxSize, Size as GenericSize,
+    GenericLengthPercentageOrNormal, GenericLengthOrNumber,
+    GenericMaxSize, GenericSize,
 };
 use crate::values::generics::NonNegative;
 use crate::values::specified::calc::CalcNode;
 use crate::values::specified::NonNegativeNumber;
-use crate::values::{CSSFloat, Either, Normal};
+use crate::values::CSSFloat;
 use crate::Zero;
 use app_units::Au;
 use cssparser::{Parser, Token};
@@ -957,7 +958,7 @@ impl NonNegativeLengthPercentageOrAuto {
 pub type NonNegativeLengthPercentage = NonNegative<LengthPercentage>;
 
 /// Either a NonNegativeLengthPercentage or the `normal` keyword.
-pub type NonNegativeLengthPercentageOrNormal = Either<NonNegativeLengthPercentage, Normal>;
+pub type NonNegativeLengthPercentageOrNormal = GenericLengthPercentageOrNormal<NonNegativeLengthPercentage>;
 
 impl From<NoCalcLength> for NonNegativeLengthPercentage {
     #[inline]