style: Add a ValueInfo trait for exposing types needed by devtools.

Most of types just derive it using proc_macro directly. Some of value
types need manual impl.

In my current plan, this new trait will be used in bug 1434130 to expose
values as well.

Bug: 1455576
Reviewed-by: emilio
MozReview-Commit-ID: LI7fy45VkRw

components/style/values/specified/align.rs

@@ -16,7 +16,7 @@ bitflags! {
     /// Constants shared by multiple CSS Box Alignment properties
     ///
     /// These constants match Gecko's `NS_STYLE_ALIGN_*` constants.
-    #[derive(MallocSizeOf, ToComputedValue)]
+    #[derive(MallocSizeOf, SpecifiedValueInfo, ToComputedValue)]
     pub struct AlignFlags: u8 {
         // Enumeration stored in the lower 5 bits:
         /// 'auto'
@@ -135,7 +135,8 @@ pub enum AxisDirection {
 /// Shared value for the `align-content` and `justify-content` properties.
 ///
 /// <https://drafts.csswg.org/css-align/#content-distribution>
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 pub struct ContentDistribution {
     primary: AlignFlags,
@@ -232,7 +233,8 @@ impl ContentDistribution {
 /// Value for the `align-content` property.
 ///
 /// <https://drafts.csswg.org/css-align/#propdef-align-content>
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub struct AlignContent(pub ContentDistribution);
 
 impl Parse for AlignContent {
@@ -264,7 +266,8 @@ impl From<AlignContent> for u16 {
 /// Value for the `justify-content` property.
 ///
 /// <https://drafts.csswg.org/css-align/#propdef-align-content>
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub struct JustifyContent(pub ContentDistribution);
 
 impl Parse for JustifyContent {
@@ -294,7 +297,8 @@ impl From<JustifyContent> for u16 {
 }
 
 /// <https://drafts.csswg.org/css-align/#self-alignment>
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub struct SelfAlignment(pub AlignFlags);
 
 impl SelfAlignment {
@@ -344,7 +348,8 @@ impl SelfAlignment {
 /// The specified value of the align-self property.
 ///
 /// <https://drafts.csswg.org/css-align/#propdef-align-self>
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub struct AlignSelf(pub SelfAlignment);
 
 impl Parse for AlignSelf {
@@ -374,7 +379,8 @@ impl From<AlignSelf> for u8 {
 /// The specified value of the justify-self property.
 ///
 /// <https://drafts.csswg.org/css-align/#propdef-justify-self>
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub struct JustifySelf(pub SelfAlignment);
 
 impl Parse for JustifySelf {
@@ -404,7 +410,8 @@ impl From<JustifySelf> for u8 {
 /// Value of the `align-items` property
 ///
 /// <https://drafts.csswg.org/css-align/#self-alignment>
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub struct AlignItems(pub AlignFlags);
 
 impl AlignItems {
@@ -443,7 +450,8 @@ impl Parse for AlignItems {
 /// Value of the `justify-items` property
 ///
 /// <https://drafts.csswg.org/css-align/#justify-items-property>
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToCss)]
 pub struct JustifyItems(pub AlignFlags);
 
 impl JustifyItems {

components/style/values/specified/angle.rs

@@ -7,7 +7,7 @@
 use cssparser::{Parser, Token};
 use parser::{Parse, ParserContext};
 use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, ToCss};
+use style_traits::{CssWriter, ParseError, SpecifiedValueInfo, ToCss};
 use values::CSSFloat;
 use values::computed::{Context, ToComputedValue};
 use values::computed::angle::Angle as ComputedAngle;
@@ -203,3 +203,5 @@ impl Angle {
         }.map_err(|()| input.new_unexpected_token_error(token.clone()))
     }
 }
+
+impl SpecifiedValueInfo for Angle {}

components/style/values/specified/background.rs

@@ -48,7 +48,8 @@ impl BackgroundSize {
 }
 
 /// One of the keywords for `background-repeat`.
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 #[allow(missing_docs)]
 pub enum BackgroundRepeatKeyword {
     Repeat,
@@ -60,7 +61,8 @@ pub enum BackgroundRepeatKeyword {
 /// The specified value for the `background-repeat` property.
 ///
 /// https://drafts.csswg.org/css-backgrounds/#the-background-repeat
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToCss)]
 pub enum BackgroundRepeat {
     /// `repeat-x`
     RepeatX,

components/style/values/specified/border.rs

@@ -20,7 +20,7 @@ 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.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum BorderSideWidth {
     /// `thin`
     Thin,
@@ -189,7 +189,8 @@ impl Parse for BorderSpacing {
 /// A single border-image-repeat keyword.
 #[allow(missing_docs)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToCss)]
 pub enum BorderImageRepeatKeyword {
     Stretch,
     Repeat,
@@ -200,7 +201,8 @@ pub enum BorderImageRepeatKeyword {
 /// The specified value for the `border-image-repeat` property.
 ///
 /// https://drafts.csswg.org/css-backgrounds/#the-border-image-repeat
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue)]
 pub struct BorderImageRepeat(pub BorderImageRepeatKeyword, pub BorderImageRepeatKeyword);
 
 impl ToCss for BorderImageRepeat {

components/style/values/specified/box.rs

@@ -9,9 +9,8 @@ use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use selectors::parser::SelectorParseErrorKind;
 use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
-use values::CustomIdent;
-use values::KeyframesName;
+use style_traits::{CssWriter, ParseError, SpecifiedValueInfo, StyleParseErrorKind, ToCss};
+use values::{CustomIdent, KeyframesName};
 use values::generics::box_::AnimationIterationCount as GenericAnimationIterationCount;
 use values::generics::box_::Perspective as GenericPerspective;
 use values::generics::box_::VerticalAlign as GenericVerticalAlign;
@@ -19,7 +18,8 @@ use values::specified::{AllowQuirks, Number};
 use values::specified::length::{LengthOrPercentage, NonNegativeLength};
 
 #[allow(missing_docs)]
-#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 /// Defines an element’s display type, which consists of
 /// the two basic qualities of how an element generates boxes
@@ -296,7 +296,8 @@ impl AnimationIterationCount {
 }
 
 /// A value for the `animation-name` property.
-#[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue)]
 pub struct AnimationName(pub Option<KeyframesName>);
 
 impl AnimationName {
@@ -339,7 +340,8 @@ impl Parse for AnimationName {
 
 #[allow(missing_docs)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 pub enum ScrollSnapType {
     None,
     Mandatory,
@@ -348,7 +350,8 @@ pub enum ScrollSnapType {
 
 #[allow(missing_docs)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 pub enum OverscrollBehavior {
     Auto,
     Contain,
@@ -357,13 +360,15 @@ pub enum OverscrollBehavior {
 
 #[allow(missing_docs)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 pub enum OverflowClipBox {
     PaddingBox,
     ContentBox,
 }
 
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 /// Provides a rendering hint to the user agent,
 /// stating what kinds of changes the author expects
 /// to perform on the element
@@ -488,6 +493,8 @@ impl Parse for TouchAction {
     }
 }
 
+impl SpecifiedValueInfo for TouchAction {}
+
 #[cfg(feature = "gecko")]
 impl_bitflags_conversions!(TouchAction);
 
@@ -598,6 +605,8 @@ impl Parse for Contain {
     }
 }
 
+impl SpecifiedValueInfo for Contain {}
+
 /// A specified value for the `perspective` property.
 pub type Perspective = GenericPerspective<NonNegativeLength>;
 

components/style/values/specified/calc.rs

@@ -9,7 +9,7 @@
 use cssparser::{AngleOrNumber, NumberOrPercentage, Parser, Token};
 use parser::ParserContext;
 use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
+use style_traits::{CssWriter, ParseError, SpecifiedValueInfo, StyleParseErrorKind, ToCss};
 use style_traits::values::specified::AllowedNumericType;
 use values::{CSSFloat, CSSInteger};
 use values::computed;
@@ -150,6 +150,8 @@ impl ToCss for CalcLengthOrPercentage {
     }
 }
 
+impl SpecifiedValueInfo for CalcLengthOrPercentage {}
+
 impl CalcNode {
     /// Tries to parse a single element in the expression, that is, a
     /// `<length>`, `<angle>`, `<time>`, `<percentage>`, according to

components/style/values/specified/color.rs

@@ -14,7 +14,8 @@ use parser::{Parse, ParserContext};
 use properties::longhands::system_colors::SystemColor;
 use std::fmt::{self, Write};
 use std::io::Write as IoWrite;
-use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss, ValueParseErrorKind};
+use style_traits::{CssType, CssWriter, ParseError, StyleParseErrorKind};
+use style_traits::{SpecifiedValueInfo, ToCss, ValueParseErrorKind};
 use super::AllowQuirks;
 use values::computed::{Color as ComputedColor, Context, ToComputedValue};
 use values::specified::calc::CalcNode;
@@ -394,7 +395,7 @@ 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, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub struct RGBAColor(pub Color);
 
 impl Parse for RGBAColor {
@@ -426,10 +427,14 @@ impl From<Color> for RGBAColor {
     }
 }
 
+impl SpecifiedValueInfo for Color {
+    const SUPPORTED_TYPES: u8 = CssType::COLOR;
+}
+
 /// Specified value for the "color" property, which resolves the `currentcolor`
 /// keyword to the parent color instead of self's color.
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, PartialEq, SpecifiedValueInfo, ToCss)]
 pub struct ColorPropertyValue(pub Color);
 
 impl ToComputedValue for ColorPropertyValue {

components/style/values/specified/counters.rs

@@ -99,7 +99,8 @@ fn is_decimal(counter_type: &CounterStyleType) -> bool {
 /// The specified value for the `content` property.
 ///
 /// https://drafts.csswg.org/css-content/#propdef-content
-#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub enum Content {
     /// `normal` reserved keyword.
     Normal,
@@ -113,7 +114,8 @@ pub enum Content {
 }
 
 /// Items for the `content` property.
-#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub enum ContentItem {
     /// Literal string content.
     String(Box<str>),

components/style/values/specified/effects.rs

@@ -35,7 +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, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub struct Factor(NumberOrPercentage);
 
 impl Factor {

components/style/values/specified/font.rs

@@ -77,7 +77,7 @@ pub const MAX_FONT_WEIGHT: f32 = 1000.;
 /// A specified font-weight value.
 ///
 /// https://drafts.csswg.org/css-fonts-4/#propdef-font-weight
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum FontWeight {
     /// `<font-weight-absolute>`
     Absolute(AbsoluteFontWeight),
@@ -154,7 +154,7 @@ impl ToComputedValue for FontWeight {
 /// An absolute font-weight value for a @font-face rule.
 ///
 /// https://drafts.csswg.org/css-fonts-4/#font-weight-absolute-values
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum AbsoluteFontWeight {
     /// A `<number>`, with the additional constraints specified in:
     ///
@@ -333,7 +333,8 @@ impl SpecifiedFontStyle {
 }
 
 /// The specified value of the `font-style` property.
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToCss)]
 #[allow(missing_docs)]
 pub enum FontStyle {
     Specified(SpecifiedFontStyle),
@@ -378,7 +379,8 @@ impl Parse for FontStyle {
 ///
 /// https://drafts.csswg.org/css-fonts-4/#font-stretch-prop
 #[allow(missing_docs)]
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToCss)]
 pub enum FontStretch {
     Stretch(Percentage),
     Keyword(FontStretchKeyword),
@@ -386,7 +388,8 @@ pub enum FontStretch {
 }
 
 /// A keyword value for `font-stretch`.
-#[derive(Clone, Copy, Debug, MallocSizeOf, Parse, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, Parse, PartialEq, SpecifiedValueInfo,
+         ToCss)]
 #[allow(missing_docs)]
 pub enum FontStretchKeyword {
     Normal,
@@ -501,7 +504,7 @@ impl ToComputedValue for FontStretch {
     }
 }
 
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 /// A specified font-size value
 pub enum FontSize {
     /// A length; e.g. 10px.
@@ -602,6 +605,8 @@ impl Parse for FontFamily {
     }
 }
 
+impl SpecifiedValueInfo for FontFamily {}
+
 /// `FamilyName::parse` is based on `SingleFontFamily::parse` and not the other way around
 /// because we want the former to exclude generic family keywords.
 impl Parse for FamilyName {
@@ -619,7 +624,7 @@ impl Parse for FamilyName {
     }
 }
 
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 /// Preserve the readability of text when font fallback occurs
 pub enum FontSizeAdjust {
     /// None variant
@@ -1079,7 +1084,7 @@ bitflags! {
     }
 }
 
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 /// Set of variant alternates
 pub enum VariantAlternates {
     /// Enables display of stylistic alternates
@@ -1104,7 +1109,7 @@ pub enum VariantAlternates {
     HistoricalForms,
 }
 
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 /// List of Variant Alternates
 pub struct VariantAlternatesList(
     #[css(if_empty = "normal", iterable)] pub Box<[VariantAlternates]>,
@@ -1125,7 +1130,7 @@ impl VariantAlternatesList {
     }
 }
 
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 /// Control over the selection of these alternate glyphs
 pub enum FontVariantAlternates {
     /// Use alternative glyph from value
@@ -1346,6 +1351,8 @@ impl ToCss for VariantEastAsian {
 #[cfg(feature = "gecko")]
 impl_gecko_keyword_conversions!(VariantEastAsian, u16);
 
+impl SpecifiedValueInfo for VariantEastAsian {}
+
 /// Asserts that all variant-east-asian matches its NS_FONT_VARIANT_EAST_ASIAN_* value.
 #[cfg(feature = "gecko")]
 #[inline]
@@ -1376,7 +1383,7 @@ pub fn assert_variant_east_asian_matches() {
 }
 
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, PartialEq, SpecifiedValueInfo, ToCss)]
 /// Allows control of glyph substitution and sizing in East Asian text.
 pub enum FontVariantEastAsian {
     /// Value variant with `variant-east-asian`
@@ -1568,6 +1575,8 @@ impl ToCss for VariantLigatures {
     }
 }
 
+impl SpecifiedValueInfo for VariantLigatures {}
+
 #[cfg(feature = "gecko")]
 impl_gecko_keyword_conversions!(VariantLigatures, u16);
 
@@ -1601,7 +1610,7 @@ pub fn assert_variant_ligatures_matches() {
 }
 
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, PartialEq, SpecifiedValueInfo, ToCss)]
 /// Ligatures and contextual forms are ways of combining glyphs
 /// to produce more harmonized forms
 pub enum FontVariantLigatures {
@@ -1798,6 +1807,8 @@ impl ToCss for VariantNumeric {
     }
 }
 
+impl SpecifiedValueInfo for VariantNumeric {}
+
 #[cfg(feature = "gecko")]
 impl_gecko_keyword_conversions!(VariantNumeric, u8);
 
@@ -1830,7 +1841,7 @@ pub fn assert_variant_numeric_matches() {
 }
 
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToCss)]
+#[derive(Clone, Debug, PartialEq, SpecifiedValueInfo, ToCss)]
 /// Specifies control over numerical forms.
 pub enum FontVariantNumeric {
     /// Value variant with `variant-numeric`
@@ -1938,7 +1949,7 @@ pub type SpecifiedFontFeatureSettings = FontSettings<FeatureTagValue<Integer>>;
 
 /// Define initial settings that apply when the font defined by an @font-face
 /// rule is rendered.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum FontFeatureSettings {
     /// Value of `FontSettings`
     Value(SpecifiedFontFeatureSettings),
@@ -1981,7 +1992,8 @@ impl Parse for FontFeatureSettings {
     }
 }
 
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue)]
 /// Whether user agents are allowed to synthesize bold or oblique font faces
 /// when a font family lacks bold or italic faces
 pub struct FontSynthesis {
@@ -2079,7 +2091,7 @@ impl From<FontSynthesis> for u8 {
     }
 }
 
-#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 /// Allows authors to explicitly specify the language system of the font,
 /// overriding the language system implied by the content language
 pub enum FontLanguageOverride {
@@ -2169,7 +2181,7 @@ pub type SpecifiedFontVariationSettings = FontSettings<VariationValue<Number>>;
 
 /// Define initial settings that apply when the font defined by an @font-face
 /// rule is rendered.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum FontVariationSettings {
     /// Value of `FontSettings`
     Value(SpecifiedFontVariationSettings),
@@ -2254,7 +2266,8 @@ impl Parse for VariationValue<Number> {
     }
 }
 
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 /// text-zoom. Enable if true, disable if false
 pub struct XTextZoom(#[css(skip)] pub bool);
 
@@ -2271,7 +2284,8 @@ impl Parse for XTextZoom {
     }
 }
 
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 /// Internal property that reflects the lang attribute
 pub struct XLang(#[css(skip)] pub Atom);
 
@@ -2297,7 +2311,7 @@ impl Parse for XLang {
 }
 
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, PartialEq, SpecifiedValueInfo, ToCss)]
 /// Specifies the minimum font size allowed due to changes in scriptlevel.
 /// Ref: https://wiki.mozilla.org/MathML:mstyle
 pub struct MozScriptMinSize(pub NoCalcLength);
@@ -2324,7 +2338,7 @@ impl Parse for MozScriptMinSize {
 }
 
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, PartialEq, SpecifiedValueInfo, ToCss)]
 /// Changes the scriptlevel in effect for the children.
 /// Ref: https://wiki.mozilla.org/MathML:mstyle
 ///
@@ -2359,7 +2373,8 @@ impl Parse for MozScriptLevel {
 }
 
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Copy, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, PartialEq, SpecifiedValueInfo, ToComputedValue,
+         ToCss)]
 /// Specifies the multiplier to be used to adjust font size
 /// due to changes in scriptlevel.
 ///

components/style/values/specified/grid.rs

@@ -104,7 +104,7 @@ pub fn parse_line_names<'i, 't>(
 /// The type of `repeat` function (only used in parsing).
 ///
 /// <https://drafts.csswg.org/css-grid/#typedef-track-repeat>
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, SpecifiedValueInfo)]
 #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 enum RepeatType {
     /// [`<auto-repeat>`](https://drafts.csswg.org/css-grid/#typedef-auto-repeat)

components/style/values/specified/image.rs

@@ -17,7 +17,8 @@ use servo_url::ServoUrl;
 use std::cmp::Ordering;
 use std::f32::consts::PI;
 use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
+use style_traits::{CssType, CssWriter, ParseError, StyleParseErrorKind};
+use style_traits::{SpecifiedValueInfo, ToCss};
 use values::{Either, None_};
 #[cfg(feature = "gecko")]
 use values::computed::{Context, Position as ComputedPosition, ToComputedValue};
@@ -54,6 +55,10 @@ pub type Gradient = generic::Gradient<
     Angle,
 >;
 
+impl SpecifiedValueInfo for Gradient {
+    const SUPPORTED_TYPES: u8 = CssType::GRADIENT;
+}
+
 /// A specified gradient kind.
 #[cfg(not(feature = "gecko"))]
 pub type GradientKind =

components/style/values/specified/inherited_box.rs

@@ -15,7 +15,7 @@ use values::specified::Angle;
 
 /// The specified value of the `image-orientation` property.
 /// https://drafts.csswg.org/css-images/#propdef-image-orientation
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo)]
 pub struct ImageOrientation {
     /// The angle specified, if any
     pub angle: Option<Angle>,

components/style/values/specified/length.rs

@@ -13,7 +13,7 @@ use font_metrics::FontMetricsQueryResult;
 use parser::{Parse, ParserContext};
 use std::cmp;
 use std::ops::{Add, Mul};
-use style_traits::{ParseError, StyleParseErrorKind};
+use style_traits::{ParseError, SpecifiedValueInfo, StyleParseErrorKind};
 use style_traits::values::specified::AllowedNumericType;
 use super::{AllowQuirks, Number, Percentage, ToComputedValue};
 use values::{Auto, CSSFloat, Either, Normal};
@@ -494,11 +494,13 @@ impl NoCalcLength {
     }
 }
 
+impl SpecifiedValueInfo for NoCalcLength {}
+
 /// An extension to `NoCalcLength` to parse `calc` expressions.
 /// This is commonly used for the `<length>` values.
 ///
 /// <https://drafts.csswg.org/css-values/#lengths>
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum Length {
     /// The internal length type that cannot parse `calc`
     NoCalc(NoCalcLength),
@@ -699,7 +701,7 @@ pub type NonNegativeLengthOrAuto = Either<NonNegativeLength, Auto>;
 
 /// A length or a percentage value.
 #[allow(missing_docs)]
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum LengthOrPercentage {
     Length(NoCalcLength),
     Percentage(computed::Percentage),
@@ -845,7 +847,7 @@ impl LengthOrPercentage {
 
 /// Either a `<length>`, a `<percentage>`, or the `auto` keyword.
 #[allow(missing_docs)]
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum LengthOrPercentageOrAuto {
     Length(NoCalcLength),
     Percentage(computed::Percentage),
@@ -1015,7 +1017,7 @@ impl Parse for NonNegativeLengthOrPercentageOrAuto {
 }
 
 /// Either a `<length>`, a `<percentage>`, or the `none` keyword.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 #[allow(missing_docs)]
 pub enum LengthOrPercentageOrNone {
     Length(NoCalcLength),
@@ -1195,7 +1197,7 @@ impl LengthOrNumber {
 ///
 /// Note that it only accepts non-negative values.
 #[allow(missing_docs)]
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum MozLength {
     LengthOrPercentageOrAuto(LengthOrPercentageOrAuto),
     ExtremumLength(ExtremumLength),
@@ -1252,7 +1254,7 @@ impl MozLength {
 
 /// A value suitable for a `max-width` or `max-height` property.
 #[allow(missing_docs)]
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum MaxLength {
     LengthOrPercentageOrNone(LengthOrPercentageOrNone),
     ExtremumLength(ExtremumLength),

components/style/values/specified/list.rs

@@ -15,7 +15,8 @@ use values::generics::CounterStyleOrNone;
 
 /// Specified and computed `list-style-type` property.
 #[cfg(feature = "gecko")]
-#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub enum ListStyleType {
     /// <counter-style> | none
     CounterStyle(CounterStyleOrNone),
@@ -77,7 +78,8 @@ impl Parse for ListStyleType {
 ///
 /// FIXME(emilio): It's a shame that this allocates all the time it's computed,
 /// probably should just be refcounted.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue)]
 pub struct Quotes(pub Box<[(Box<str>, Box<str>)]>);
 
 impl ToCss for Quotes {

components/style/values/specified/mod.rs

@@ -13,7 +13,7 @@ use num_traits::One;
 use parser::{Parse, ParserContext};
 use std::f32;
 use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
+use style_traits::{CssWriter, ParseError, SpecifiedValueInfo, StyleParseErrorKind, ToCss};
 use style_traits::values::specified::AllowedNumericType;
 use super::{Auto, CSSFloat, CSSInteger, Either};
 use super::computed::{Context, ToComputedValue};
@@ -149,8 +149,8 @@ fn parse_number_with_clamping_mode<'i, 't>(
 // FIXME(emilio): Should move to border.rs
 #[allow(missing_docs)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Ord, Parse, PartialEq, PartialOrd,
-         ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Ord, Parse, PartialEq,
+         PartialOrd, SpecifiedValueInfo, ToComputedValue, ToCss)]
 pub enum BorderStyle {
     None = -1,
     Solid = 6,
@@ -273,6 +273,8 @@ impl ToCss for Number {
     }
 }
 
+impl SpecifiedValueInfo for Number {}
+
 impl From<Number> for f32 {
     #[inline]
     fn from(n: Number) -> Self {
@@ -326,7 +328,8 @@ impl Parse for GreaterThanOrEqualToOneNumber {
 ///
 /// FIXME(emilio): Should probably use Either.
 #[allow(missing_docs)]
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToCss)]
 pub enum NumberOrPercentage {
     Percentage(Percentage),
     Number(Number),
@@ -364,7 +367,8 @@ impl Parse for NumberOrPercentage {
 }
 
 #[allow(missing_docs)]
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd,
+         SpecifiedValueInfo, ToCss)]
 pub struct Opacity(Number);
 
 impl Parse for Opacity {
@@ -533,6 +537,8 @@ impl ToCss for Integer {
     }
 }
 
+impl SpecifiedValueInfo for Integer {}
+
 /// A wrapper of Integer, with value >= 1.
 pub type PositiveInteger = GreaterThanOrEqualToOne<Integer>;
 
@@ -562,7 +568,7 @@ pub type GridLine = GenericGridLine<Integer>;
 /// `<grid-template-rows> | <grid-template-columns>`
 pub type GridTemplateComponent = GenericGridTemplateComponent<LengthOrPercentage, Integer>;
 
-#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo)]
 /// rect(<top>, <left>, <bottom>, <right>) used by clip and image-region
 pub struct ClipRect {
     /// <top> (<length> | <auto>)
@@ -846,3 +852,5 @@ impl ToCss for Attr {
         dest.write_str(")")
     }
 }
+
+impl SpecifiedValueInfo for Attr {}

components/style/values/specified/outline.rs

@@ -10,8 +10,8 @@ use selectors::parser::SelectorParseErrorKind;
 use style_traits::ParseError;
 use values::specified::BorderStyle;
 
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Ord, PartialEq, PartialOrd, ToComputedValue,
-         ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Ord, PartialEq, PartialOrd,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 /// <https://drafts.csswg.org/css-ui/#propdef-outline-style>
 pub enum OutlineStyle {
     /// auto

components/style/values/specified/percentage.rs

@@ -7,7 +7,7 @@
 use cssparser::{Parser, Token};
 use parser::{Parse, ParserContext};
 use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, ToCss};
+use style_traits::{CssWriter, ParseError, SpecifiedValueInfo, ToCss};
 use style_traits::values::specified::AllowedNumericType;
 use values::{serialize_percentage, CSSFloat};
 use values::computed::{Context, ToComputedValue};
@@ -158,3 +158,5 @@ impl ToComputedValue for Percentage {
         Percentage::new(computed.0)
     }
 }
+
+impl SpecifiedValueInfo for Percentage {}

components/style/values/specified/position.rs

@@ -34,7 +34,7 @@ pub type HorizontalPosition = PositionComponent<X>;
 pub type VerticalPosition = PositionComponent<Y>;
 
 /// The specified value of a component of a CSS `<position>`.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum PositionComponent<S> {
     /// `center`
     Center,
@@ -45,7 +45,8 @@ pub enum PositionComponent<S> {
 }
 
 /// A keyword for the X direction.
-#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 #[allow(missing_docs)]
 pub enum X {
     Left,
@@ -53,7 +54,8 @@ pub enum X {
 }
 
 /// A keyword for the Y direction.
-#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 #[allow(missing_docs)]
 pub enum Y {
     Top,
@@ -409,7 +411,8 @@ impl ToCss for LegacyPosition {
     }
 }
 
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 /// Auto-placement algorithm Option
 pub enum AutoFlow {
     /// The auto-placement algorithm places items by filling each row in turn,
@@ -420,7 +423,8 @@ pub enum AutoFlow {
     Column,
 }
 
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue)]
 /// Controls how the auto-placement algorithm works
 /// specifying exactly how auto-placed items get flowed into the grid
 pub struct GridAutoFlow {
@@ -533,7 +537,7 @@ impl From<GridAutoFlow> for u8 {
 }
 
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Debug, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, PartialEq, SpecifiedValueInfo, ToComputedValue, ToCss)]
 /// https://drafts.csswg.org/css-grid/#named-grid-area
 pub struct TemplateAreas {
     /// `named area` containing for each template area
@@ -639,7 +643,8 @@ impl Parse for TemplateAreas {
 }
 
 /// Arc type for `Arc<TemplateAreas>`
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub struct TemplateAreasArc(#[ignore_malloc_size_of = "Arc"] pub Arc<TemplateAreas>);
 
 impl Parse for TemplateAreasArc {
@@ -654,7 +659,7 @@ impl Parse for TemplateAreasArc {
 }
 
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, SpecifiedValueInfo)]
 /// Not associated with any particular grid item, but can
 /// be referenced from the grid-placement properties.
 pub struct NamedArea {

components/style/values/specified/svg.rs

@@ -173,7 +173,8 @@ const PAINT_ORDER_MASK: u8 = 0b11;
 ///
 /// Higher priority values, i.e. the values specified first,
 /// will be painted first (and may be covered by paintings of lower priority)
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue)]
 pub struct SVGPaintOrder(pub u8);
 
 impl SVGPaintOrder {
@@ -280,7 +281,8 @@ impl ToCss for SVGPaintOrder {
 
 /// Specified MozContextProperties value.
 /// Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-context-properties)
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub struct MozContextProperties(pub CustomIdent);
 
 impl Parse for MozContextProperties {

components/style/values/specified/table.rs

@@ -8,7 +8,8 @@ use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use style_traits::{ParseError, StyleParseErrorKind};
 
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 /// span. for `<col span>` pres attr
 pub struct XSpan(#[css(skip)] pub i32);
 

components/style/values/specified/text.rs

@@ -158,7 +158,7 @@ impl ToComputedValue for LineHeight {
 }
 
 /// A generic value for the `text-overflow` property.
-#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum TextOverflowSide {
     /// Clip inline content.
     Clip,
@@ -192,7 +192,7 @@ impl Parse for TextOverflowSide {
     }
 }
 
-#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 /// text-overflow. Specifies rendering when inline content overflows its line box edge.
 pub struct TextOverflow {
     /// First value. Applies to end line box edge if no second is supplied; line-left edge otherwise.
@@ -252,7 +252,7 @@ impl ToComputedValue for TextOverflow {
 }
 
 bitflags! {
-    #[derive(MallocSizeOf, ToComputedValue)]
+    #[derive(MallocSizeOf, SpecifiedValueInfo, ToComputedValue)]
     /// Specified keyword values for the text-decoration-line property.
     pub struct TextDecorationLine: u8 {
         /// No text decoration line is specified
@@ -357,7 +357,8 @@ impl Parse for TextDecorationLine {
 macro_rules! define_text_align_keyword {
     ($($name: ident => $discriminant: expr,)+) => {
         /// Specified value of text-align keyword value.
-        #[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+        #[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq,
+                 SpecifiedValueInfo, ToComputedValue, ToCss)]
         #[allow(missing_docs)]
         pub enum TextAlignKeyword {
             $(
@@ -417,7 +418,7 @@ impl TextAlignKeyword {
 
 /// Specified value of text-align property.
 #[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, SpecifiedValueInfo)]
 pub enum TextAlign {
     /// Keyword value of text-align property.
     Keyword(TextAlignKeyword),
@@ -534,7 +535,7 @@ impl ToComputedValue for TextAlign {
 }
 
 /// Specified value of text-emphasis-style property.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum TextEmphasisStyle {
     /// <fill> <shape>
     Keyword(TextEmphasisKeywordValue),
@@ -545,7 +546,7 @@ pub enum TextEmphasisStyle {
 }
 
 /// Keyword value for the text-emphasis-style property
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum TextEmphasisKeywordValue {
     /// <fill>
     Fill(TextEmphasisFillMode),
@@ -574,7 +575,8 @@ impl TextEmphasisKeywordValue {
 }
 
 /// Fill mode for the text-emphasis-style property
-#[derive(Clone, Copy, Debug, MallocSizeOf, Parse, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, Parse, PartialEq, SpecifiedValueInfo,
+         ToCss)]
 pub enum TextEmphasisFillMode {
     /// `filled`
     Filled,
@@ -583,7 +585,8 @@ pub enum TextEmphasisFillMode {
 }
 
 /// Shape keyword for the text-emphasis-style property
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToCss)]
 pub enum TextEmphasisShapeKeyword {
     /// `dot`
     Dot,
@@ -709,7 +712,8 @@ impl Parse for TextEmphasisStyle {
 }
 
 /// The allowed horizontal values for the `text-emphasis-position` property.
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 pub enum TextEmphasisHorizontalWritingModeValue {
     /// Draw marks over the text in horizontal writing mode.
     Over,
@@ -718,7 +722,8 @@ pub enum TextEmphasisHorizontalWritingModeValue {
 }
 
 /// The allowed vertical values for the `text-emphasis-position` property.
-#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToComputedValue, ToCss)]
 pub enum TextEmphasisVerticalWritingModeValue {
     /// Draws marks to the right of the text in vertical writing mode.
     Right,
@@ -727,7 +732,8 @@ pub enum TextEmphasisVerticalWritingModeValue {
 }
 
 /// Specified value of `text-emphasis-position` property.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
 pub struct TextEmphasisPosition(
     pub TextEmphasisHorizontalWritingModeValue,
     pub TextEmphasisVerticalWritingModeValue,

components/style/values/specified/time.rs

@@ -7,7 +7,7 @@
 use cssparser::{Parser, Token};
 use parser::{Parse, ParserContext};
 use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
+use style_traits::{CssWriter, ParseError, SpecifiedValueInfo, StyleParseErrorKind, ToCss};
 use style_traits::values::specified::AllowedNumericType;
 use values::CSSFloat;
 use values::computed::{Context, ToComputedValue};
@@ -165,3 +165,5 @@ impl ToCss for Time {
         Ok(())
     }
 }
+
+impl SpecifiedValueInfo for Time {}

components/style/values/specified/transform.rs

@@ -7,7 +7,7 @@
 use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use selectors::parser::SelectorParseErrorKind;
-use style_traits::{ParseError, StyleParseErrorKind};
+use style_traits::{CssType, ParseError, SpecifiedValueInfo, StyleParseErrorKind};
 use values::computed::{Context, LengthOrPercentage as ComputedLengthOrPercentage};
 use values::computed::{Percentage as ComputedPercentage, ToComputedValue};
 use values::computed::transform::TimingFunction as ComputedTimingFunction;
@@ -233,7 +233,7 @@ impl Parse for Transform {
 }
 
 /// The specified value of a component of a CSS `<transform-origin>`.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
 pub enum OriginComponent<S> {
     /// `center`
     Center,
@@ -246,6 +246,10 @@ pub enum OriginComponent<S> {
 /// A specified timing function.
 pub type TimingFunction = generic::TimingFunction<Integer, Number>;
 
+impl SpecifiedValueInfo for TimingFunction {
+    const SUPPORTED_TYPES: u8 = CssType::TIMING_FUNCTION;
+}
+
 impl Parse for TransformOrigin {
     fn parse<'i, 't>(
         context: &ParserContext,

components/style/values/specified/ui.rs

@@ -10,7 +10,8 @@ use std::fmt::{self, Write};
 use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
 
 /// Specified value of `-moz-force-broken-image-icon`
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue)]
 pub struct MozForceBrokenImageIcon(pub bool);
 
 impl MozForceBrokenImageIcon {