style: Use Rust types for some misc properties.

-moz-tab-size, border-image-outset and border-image-slice.

This is not a particularly interesting patch, just removes some code. We can
remove way more code when a few related properties are also ported.

Differential Revision: https://phabricator.services.mozilla.com/D19825

components/style/values/computed/length.rs

@@ -6,9 +6,10 @@
 
 use super::{Context, Number, Percentage, ToComputedValue};
 use crate::values::animated::ToAnimatedValue;
+use crate::values::computed::NonNegativeNumber;
 use crate::values::distance::{ComputeSquaredDistance, SquaredDistance};
 use crate::values::generics::length as generics;
-use crate::values::generics::length::{MaxSize as GenericMaxSize, Size as GenericSize};
+use crate::values::generics::length::{MaxSize as GenericMaxSize, Size as GenericSize, GenericLengthOrNumber};
 use crate::values::generics::transform::IsZeroLength;
 use crate::values::generics::NonNegative;
 use crate::values::specified::length::ViewportPercentageLength;
@@ -678,6 +679,15 @@ impl ToCss for CSSPixelLength {
     }
 }
 
+impl Add for CSSPixelLength {
+    type Output = Self;
+
+    #[inline]
+    fn add(self, other: Self) -> Self {
+        Self::new(self.px() + other.px())
+    }
+}
+
 impl Neg for CSSPixelLength {
     type Output = Self;
 
@@ -708,15 +718,7 @@ pub type Length = CSSPixelLength;
 pub type LengthOrAuto = Either<Length, Auto>;
 
 /// Either a computed `<length>` or a `<number>` value.
-pub type LengthOrNumber = Either<Length, Number>;
-
-impl LengthOrNumber {
-    /// Returns `0`.
-    #[inline]
-    pub fn zero() -> Self {
-        Either::Second(0.)
-    }
-}
+pub type LengthOrNumber = GenericLengthOrNumber<Length, Number>;
 
 /// Either a computed `<length>` or the `normal` keyword.
 pub type LengthOrNormal = Either<Length, Normal>;
@@ -776,13 +778,6 @@ impl NonNegativeLength {
     }
 }
 
-impl Add<NonNegativeLength> for NonNegativeLength {
-    type Output = Self;
-    fn add(self, other: Self) -> Self {
-        NonNegativeLength::new(self.px() + other.px())
-    }
-}
-
 impl From<Length> for NonNegativeLength {
     #[inline]
     fn from(len: Length) -> Self {
@@ -813,6 +808,9 @@ pub type NonNegativeLengthOrNormal = Either<NonNegativeLength, Normal>;
 /// Either a computed NonNegativeLengthPercentage or the `normal` keyword.
 pub type NonNegativeLengthPercentageOrNormal = Either<NonNegativeLengthPercentage, Normal>;
 
+/// Either a non-negative `<length>` or a `<number>`.
+pub type NonNegativeLengthOrNumber = GenericLengthOrNumber<NonNegativeLength, NonNegativeNumber>;
+
 /// A type for possible values for min- and max- flavors of width, height,
 /// block-size, and inline-size.
 #[allow(missing_docs)]

components/style/values/computed/mod.rs

@@ -61,7 +61,7 @@ pub use self::font::{MozScriptLevel, MozScriptMinSize, MozScriptSizeMultiplier,
 pub use self::gecko::ScrollSnapPoint;
 pub use self::image::{Gradient, GradientItem, Image, ImageLayer, LineDirection, MozImageRect};
 pub use self::length::{CSSPixelLength, ExtremumLength, NonNegativeLength};
-pub use self::length::{Length, LengthOrNumber, LengthPercentage};
+pub use self::length::{Length, LengthOrNumber, LengthPercentage, NonNegativeLengthOrNumber};
 pub use self::length::{LengthPercentageOrAuto, MaxSize, Size};
 pub use self::length::{NonNegativeLengthPercentage, NonNegativeLengthPercentageOrAuto};
 #[cfg(feature = "gecko")]
@@ -71,13 +71,13 @@ pub use self::motion::OffsetPath;
 pub use self::outline::OutlineStyle;
 pub use self::percentage::{NonNegativePercentage, Percentage};
 pub use self::position::{GridAutoFlow, GridTemplateAreas, Position, ZIndex};
-pub use self::rect::LengthOrNumberRect;
+pub use self::rect::NonNegativeLengthOrNumberRect;
 pub use self::resolution::Resolution;
 pub use self::svg::MozContextProperties;
 pub use self::svg::{SVGLength, SVGOpacity, SVGPaint, SVGPaintKind};
 pub use self::svg::{SVGPaintOrder, SVGStrokeDashArray, SVGWidth};
 pub use self::table::XSpan;
-pub use self::text::{InitialLetter, LetterSpacing, LineHeight, MozTabSize};
+pub use self::text::{InitialLetter, LetterSpacing, LineHeight};
 pub use self::text::{OverflowWrap, TextOverflow, WordSpacing};
 pub use self::text::{TextAlign, TextEmphasisPosition, TextEmphasisStyle};
 pub use self::time::Time;
@@ -536,6 +536,7 @@ impl From<GreaterThanOrEqualToOneNumber> for CSSFloat {
 
 #[allow(missing_docs)]
 #[derive(Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[repr(C, u8)]
 pub enum NumberOrPercentage {
     Percentage(Percentage),
     Number(Number),

components/style/values/computed/rect.rs

@@ -4,8 +4,8 @@
 
 //! Computed types for CSS borders.
 
-use crate::values::computed::length::LengthOrNumber;
+use crate::values::computed::length::NonNegativeLengthOrNumber;
 use crate::values::generics::rect::Rect;
 
 /// A specified rectangle made of four `<length-or-number>` values.
-pub type LengthOrNumberRect = Rect<LengthOrNumber>;
+pub type NonNegativeLengthOrNumberRect = Rect<NonNegativeLengthOrNumber>;

components/style/values/computed/text.rs

@@ -10,7 +10,6 @@ use crate::values::computed::length::{Length, LengthPercentage};
 use crate::values::computed::{NonNegativeLength, NonNegativeNumber};
 use crate::values::generics::text::InitialLetter as GenericInitialLetter;
 use crate::values::generics::text::LineHeight as GenericLineHeight;
-use crate::values::generics::text::MozTabSize as GenericMozTabSize;
 use crate::values::generics::text::Spacing;
 use crate::values::specified::text::TextOverflowSide;
 use crate::values::specified::text::{TextEmphasisFillMode, TextEmphasisShapeKeyword};
@@ -124,9 +123,6 @@ impl TextDecorationsInEffect {
     }
 }
 
-/// A specified value for the `-moz-tab-size` property.
-pub type MozTabSize = GenericMozTabSize<NonNegativeNumber, NonNegativeLength>;
-
 /// computed value for the text-emphasis-style property
 #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum TextEmphasisStyle {