servo: Merge #16960 - Derive HasViewportPercentage 🍷 (from servo:derive-all-the-things); r=emilio

Source-Repo: https://github.com/servo/servo Source-Revision: 4f0b24ac0c3bd04104d705898ceb4d06ef5ea092 --HG-- rename : servo/components/domobject_derive/Cargo.toml => servo/components/style_derive/Cargo.toml extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear extra : subtree_revision : 498aeee06ee32907459c0ba0c29d40189438fb0b
2017-05-20 11:34:36 -05:00 · 2017-05-20 11:34:36 -05:00 · b991e3f4f2
--- a/servo/Cargo.lock
+++ b/servo/Cargo.lock
@ -605,7 +605,7 @@ name = "deny_public_fields"
 version = "0.0.1"
 dependencies = [
 "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "synstructure 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synstructure 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
@ -1146,7 +1146,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "synstructure 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synstructure 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
@ -1346,7 +1346,7 @@ version = "0.0.1"
 dependencies = [
 "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "synstructure 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synstructure 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
@ -2860,6 +2860,7 @@ dependencies = [
 "servo_config 0.0.1",
 "servo_url 0.0.1",
 "smallvec 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "style_derive 0.0.1",
 "style_traits 0.0.1",
 "time 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 "toml 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
@ -2867,6 +2868,15 @@ dependencies = [
 "walkdir 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "style_derive"
 version = "0.0.1"
 dependencies = [
 "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
 "synstructure 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "style_tests"
 version = "0.0.1"
@ -2946,7 +2956,7 @@ dependencies = [
 [[package]]
 name = "synstructure"
-version = "0.5.0"
+version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
@ -3651,7 +3661,7 @@ dependencies = [
 "checksum swapper 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "3ca610b32bb8bfc5e7f705480c3a1edfeb70b6582495d343872c8bee0dcf758c"
 "checksum syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)" = "d3b891b9015c88c576343b9b3e41c2c11a51c219ef067b264bd9c8aa9b441dad"
 "checksum synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a393066ed9010ebaed60b9eafa373d4b1baac186dd7e008555b0f702b51945b6"
-"checksum synstructure 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5ccc9780bf1aa601943988c2876ab22413c01ad1739689aa6af18d0aa0b3f38b"
+"checksum synstructure 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "cf318c34a2f8381a4f3d4db2c91b45bca2b1cd8cbe56caced900647be164800c"
 "checksum syntex 0.58.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a8f5e3aaa79319573d19938ea38d068056b826db9883a5d47f86c1cecc688f0e"
 "checksum syntex_errors 0.58.1 (registry+https://github.com/rust-lang/crates.io-index)" = "867cc5c2d7140ae7eaad2ae9e8bf39cb18a67ca651b7834f88d46ca98faadb9c"
 "checksum syntex_pos 0.58.1 (registry+https://github.com/rust-lang/crates.io-index)" = "13ad4762fe52abc9f4008e85c4fb1b1fe3aa91ccb99ff4826a439c7c598e1047"
--- a/servo/components/style/Cargo.toml
+++ b/servo/components/style/Cargo.toml
@ -63,6 +63,7 @@ serde_derive = {version = "0.9", optional = true}
 servo_atoms = {path = "../atoms", optional = true}
 servo_config = {path = "../config", optional = true}
 smallvec = "0.3.3"
 style_derive = {path = "../style_derive"}
 style_traits = {path = "../style_traits"}
 servo_url = {path = "../url", optional = true}
 time = "0.1"
--- a/servo/components/style/lib.rs
+++ b/servo/components/style/lib.rs
@ -79,6 +79,8 @@ extern crate selectors;
 #[cfg(feature = "servo")] extern crate servo_url;
 extern crate smallvec;
 #[macro_use]
 extern crate style_derive;
 #[macro_use]
 extern crate style_traits;
 extern crate time;
 #[allow(unused_extern_crates)]
--- a/servo/components/style/macros.rs
+++ b/servo/components/style/macros.rs
@ -38,19 +38,6 @@ macro_rules! define_numbered_css_keyword_enum {
    }
 }
 /// A macro used to implement HasViewportPercentage trait
 /// for a given type that may never contain viewport units.
 macro_rules! no_viewport_percentage {
    ($name: ident) => {
        impl $crate::values::HasViewportPercentage for $name {
            #[inline]
            fn has_viewport_percentage(&self) -> bool {
                false
            }
        }
    };
 }
 /// A macro for implementing `ComputedValueAsSpecified`, `Parse`
 /// and `HasViewportPercentage` traits for the enums defined
 /// using `define_css_keyword_enum` macro.
--- a/servo/components/style/properties/helpers.mako.rs
+++ b/servo/components/style/properties/helpers.mako.rs
@ -13,8 +13,11 @@
    <%def name="predefined_type_inner(name, type, initial_value, parse_method)">
        #[allow(unused_imports)]
        use app_units::Au;
        #[allow(unused_imports)]
        use cssparser::{Color as CSSParserColor, RGBA};
        #[allow(unused_imports)]
        use values::specified::AllowQuirks;
        #[allow(unused_imports)]
        use smallvec::SmallVec;
        pub use values::specified::${type} as SpecifiedValue;
        pub mod computed_value {
@ -78,22 +81,22 @@
        % if not gecko_only:
            use smallvec::SmallVec;
            use std::fmt;
            #[allow(unused_imports)]
            use values::HasViewportPercentage;
            use style_traits::ToCss;
            impl HasViewportPercentage for SpecifiedValue {
                fn has_viewport_percentage(&self) -> bool {
                    let &SpecifiedValue(ref vec) = self;
                    vec.iter().any(|ref x| x.has_viewport_percentage())
                }
            }
            pub mod single_value {
                #[allow(unused_imports)]
                use cssparser::Parser;
                #[allow(unused_imports)]
                use parser::{Parse, ParserContext};
                #[allow(unused_imports)]
                use properties::ShorthandId;
                #[allow(unused_imports)]
                use values::computed::{Context, ToComputedValue};
                #[allow(unused_imports)]
                use values::{computed, specified};
                #[allow(unused_imports)]
                use values::{Auto, Either, None_, Normal};
                ${caller.body()}
            }
@ -168,7 +171,7 @@
            }
            /// The specified value of ${name}.
-            #[derive(Debug, Clone, PartialEq)]
+            #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
            #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
            pub struct SpecifiedValue(pub Vec<single_value::SpecifiedValue>);
@ -205,6 +208,7 @@
            }
            pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
                #[allow(unused_imports)]
                use parser::parse_space_or_comma_separated;
                <%
@ -260,22 +264,35 @@
    %>
    /// ${property.spec}
    pub mod ${property.ident} {
        #![allow(unused_imports)]
        % if not property.derived_from:
            #[allow(unused_imports)]
            use cssparser::Parser;
            #[allow(unused_imports)]
            use parser::{Parse, ParserContext};
            #[allow(unused_imports)]
            use properties::{UnparsedValue, ShorthandId};
        % endif
        #[allow(unused_imports)]
        use values::{Auto, Either, None_, Normal};
        #[allow(unused_imports)]
        use cascade_info::CascadeInfo;
        #[allow(unused_imports)]
        use error_reporting::ParseErrorReporter;
        #[allow(unused_imports)]
        use properties::longhands;
        #[allow(unused_imports)]
        use properties::{DeclaredValue, LonghandId, LonghandIdSet};
        #[allow(unused_imports)]
        use properties::{CSSWideKeyword, ComputedValues, PropertyDeclaration};
        #[allow(unused_imports)]
        use properties::style_structs;
        #[allow(unused_imports)]
        use stylearc::Arc;
        #[allow(unused_imports)]
        use values::computed::{Context, ToComputedValue};
        #[allow(unused_imports)]
        use values::{computed, generics, specified};
        #[allow(unused_imports)]
        use Atom;
        ${caller.body()}
        #[allow(unused_variables)]
@ -461,7 +478,6 @@
        keyword = keyword=Keyword(name, values, **keyword_kwargs)
    %>
    <%call expr="longhand(name, keyword=Keyword(name, values, **keyword_kwargs), **kwargs)">
        use values::HasViewportPercentage;
        use properties::longhands::system_font::SystemFont;
        use std::fmt;
        use style_traits::ToCss;
@ -583,7 +599,6 @@
            impl ComputedValueAsSpecified for SpecifiedValue {}
        % endif
        use values::HasViewportPercentage;
        no_viewport_percentage!(SpecifiedValue);
    </%call>
 </%def>
@ -745,7 +760,6 @@
    % if shorthand:
    /// ${shorthand.spec}
    pub mod ${shorthand.ident} {
        #[allow(unused_imports)]
        use cssparser::Parser;
        use parser::ParserContext;
        use properties::{PropertyDeclaration, SourcePropertyDeclaration, MaybeBoxed};
--- a/servo/components/style/properties/longhand/background.mako.rs
+++ b/servo/components/style/properties/longhand/background.mako.rs
@ -34,7 +34,6 @@ ${helpers.predefined_type("background-image", "ImageLayer",
                          spec="https://drafts.csswg.org/css-backgrounds/#the-background-repeat">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    define_css_keyword_enum!(RepeatKeyword:
                             "repeat" => Repeat,
@ -163,11 +162,8 @@ ${helpers.single_keyword("background-origin",
 <%helpers:vector_longhand name="background-size" animation_value_type="ComputedValue" extra_prefixes="webkit"
                          spec="https://drafts.csswg.org/css-backgrounds/#the-background-size">
    use cssparser::Token;
    use std::ascii::AsciiExt;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    #[allow(missing_docs)]
    pub mod computed_value {
@ -236,13 +232,7 @@ ${helpers.single_keyword("background-origin",
        }
    }
-    impl HasViewportPercentage for ExplicitSize {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            return self.width.has_viewport_percentage() || self.height.has_viewport_percentage();
        }
    }
    #[derive(Clone, PartialEq, Debug)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    #[allow(missing_docs)]
    pub struct ExplicitSize {
@ -266,16 +256,7 @@ ${helpers.single_keyword("background-origin",
        }
    }
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            match *self {
                SpecifiedValue::Explicit(ref explicit_size) => explicit_size.has_viewport_percentage(),
                _ => false
            }
        }
    }
    #[derive(Clone, PartialEq, Debug)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub enum SpecifiedValue {
        Explicit(ExplicitSize),
--- a/servo/components/style/properties/longhand/border.mako.rs
+++ b/servo/components/style/properties/longhand/border.mako.rs
@ -62,7 +62,6 @@ ${helpers.gecko_keyword_conversion(Keyword('border-style',
                       products="gecko">
        use std::fmt;
        use style_traits::ToCss;
        use values::HasViewportPercentage;
        use values::specified::CSSColor;
        no_viewport_percentage!(SpecifiedValue);
@ -205,20 +204,8 @@ ${helpers.predefined_type("border-image-source", "ImageLayer",
                   spec="https://drafts.csswg.org/css-backgrounds/#border-image-outset">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::specified::{LengthOrNumber, Number};
    impl HasViewportPercentage for SpecifiedValue {
        fn has_viewport_percentage(&self) -> bool {
            let mut viewport_percentage = false;
            for value in self.0.iter() {
                let vp = value.has_viewport_percentage();
                viewport_percentage = vp || viewport_percentage;
            }
            viewport_percentage
        }
    }
    pub mod computed_value {
        use values::computed::LengthOrNumber;
        #[derive(Debug, Clone, PartialEq)]
@ -227,7 +214,7 @@ ${helpers.predefined_type("border-image-source", "ImageLayer",
                     pub LengthOrNumber, pub LengthOrNumber);
    }
-    #[derive(Debug, Clone, PartialEq)]
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub struct SpecifiedValue(pub Vec<LengthOrNumber>);
@ -321,13 +308,11 @@ ${helpers.predefined_type("border-image-source", "ImageLayer",
                   spec="https://drafts.csswg.org/css-backgrounds/#border-image-repeat">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    pub mod computed_value {
        pub use super::RepeatKeyword;
        use values::computed;
        #[derive(Debug, Clone, PartialEq)]
        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
@ -399,23 +384,8 @@ ${helpers.predefined_type("border-image-source", "ImageLayer",
                   spec="https://drafts.csswg.org/css-backgrounds/#border-image-width">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::specified::{LengthOrPercentage, Number};
    impl HasViewportPercentage for SpecifiedValue {
        fn has_viewport_percentage(&self) -> bool {
            let mut viewport_percentage = false;
            for value in self.0.clone() {
                let vp = match value {
                    SingleSpecifiedValue::LengthOrPercentage(len) => len.has_viewport_percentage(),
                    _ => false,
                };
                viewport_percentage = vp || viewport_percentage;
            }
            viewport_percentage
        }
    }
    pub mod computed_value {
        use values::computed::{LengthOrPercentage, Number};
        #[derive(Debug, Clone, PartialEq)]
@ -432,7 +402,7 @@ ${helpers.predefined_type("border-image-source", "ImageLayer",
        }
    }
-    #[derive(Debug, Clone, PartialEq)]
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub struct SpecifiedValue(pub Vec<SingleSpecifiedValue>);
@ -458,7 +428,7 @@ ${helpers.predefined_type("border-image-source", "ImageLayer",
        }
    }
-    #[derive(Debug, Clone, PartialEq)]
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub enum SingleSpecifiedValue {
        LengthOrPercentage(LengthOrPercentage),
@ -599,7 +569,6 @@ ${helpers.predefined_type("border-image-source", "ImageLayer",
                   spec="https://drafts.csswg.org/css-backgrounds/#border-image-slice">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::NumberOrPercentage as ComputedNumberOrPercentage;
    use values::specified::{NumberOrPercentage, Percentage};
--- a/servo/components/style/properties/longhand/box.mako.rs
+++ b/servo/components/style/properties/longhand/box.mako.rs
@ -31,7 +31,6 @@
    %>
    use values::computed::ComputedValueAsSpecified;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    pub mod computed_value {
@ -170,7 +169,6 @@ ${helpers.single_keyword("position", "static absolute relative fixed",
                                  gecko_inexhaustive="True"
                                  gecko_ffi_name="mFloat"
                                  spec="https://drafts.csswg.org/css-box/#propdef-float">
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    impl ToComputedValue for SpecifiedValue {
        type ComputedValue = computed_value::T;
@ -209,7 +207,6 @@ ${helpers.single_keyword("position", "static absolute relative fixed",
                                  gecko_enum_prefix="StyleClear"
                                  gecko_ffi_name="mBreakType"
                                  spec="https://www.w3.org/TR/CSS2/visuren.html#flow-control">
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    impl ToComputedValue for SpecifiedValue {
        type ComputedValue = computed_value::T;
@ -263,7 +260,6 @@ ${helpers.single_keyword("position", "static absolute relative fixed",
                   spec="https://www.w3.org/TR/CSS2/visudet.html#propdef-vertical-align">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::specified::AllowQuirks;
    <% vertical_align = data.longhands_by_name["vertical-align"] %>
@ -274,18 +270,9 @@ ${helpers.single_keyword("position", "static absolute relative fixed",
    ${helpers.gecko_keyword_conversion(vertical_align.keyword)}
    impl HasViewportPercentage for SpecifiedValue {
        fn has_viewport_percentage(&self) -> bool {
            match *self {
                SpecifiedValue::LengthOrPercentage(ref length) => length.has_viewport_percentage(),
                _ => false
            }
        }
    }
    /// The `vertical-align` value.
    #[allow(non_camel_case_types)]
-    #[derive(Debug, Clone, PartialEq)]
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub enum SpecifiedValue {
        % for keyword in vertical_align_keywords:
@ -321,10 +308,9 @@ ${helpers.single_keyword("position", "static absolute relative fixed",
    /// The computed value for `vertical-align`.
    pub mod computed_value {
        use app_units::Au;
        use std::fmt;
        use style_traits::ToCss;
-        use values::{CSSFloat, computed};
+        use values::computed;
        /// The keywords are the same, and the `LengthOrPercentage` is computed
        /// here.
@ -426,7 +412,6 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
    use values::specified::Time;
    pub use values::specified::Time as SpecifiedValue;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    pub mod computed_value {
@ -458,7 +443,6 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
    use values::specified::Number;
    use euclid::point::{Point2D, TypedPoint2D};
    use std::fmt;
    use std::marker::PhantomData;
    use style_traits::ToCss;
    // FIXME: This could use static variables and const functions when they are available.
@ -499,7 +483,6 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
    pub mod computed_value {
        use euclid::point::Point2D;
        use parser::{Parse, ParserContext};
        use std::fmt;
        use style_traits::ToCss;
        use super::FunctionKeyword;
@ -764,7 +747,6 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
        }
    }
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    #[inline]
@ -795,8 +777,6 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
    pub use properties::animated_properties::TransitionProperty as SpecifiedValue;
    pub mod computed_value {
        use std::fmt;
        use style_traits::ToCss;
        // NB: Can't generate the type here because it needs all the longhands
        // generated beforehand.
        pub use super::SpecifiedValue as T;
@ -810,7 +790,6 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
        TransitionProperty::All
    }
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    impl ComputedValueAsSpecified for SpecifiedValue { }
@ -839,10 +818,9 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
                          spec="https://drafts.csswg.org/css-animations/#propdef-animation-name">
    use Atom;
    use std::fmt;
    use std::ops::Deref;
    use style_traits::ToCss;
    use values::computed::ComputedValueAsSpecified;
-    use values::{HasViewportPercentage, KeyframesName};
+    use values::KeyframesName;
    pub mod computed_value {
        pub use super::SpecifiedValue as T;
@ -937,7 +915,6 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
    use std::fmt;
    use style_traits::ToCss;
    use values::computed::ComputedValueAsSpecified;
    use values::HasViewportPercentage;
    pub mod computed_value {
        pub use super::SpecifiedValue as T;
@ -1045,18 +1022,8 @@ ${helpers.single_keyword("animation-fill-mode",
                   spec="Nonstandard (https://www.w3.org/TR/2015/WD-css-snappoints-1-20150326/#scroll-snap-points)">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::specified::LengthOrPercentage;
    impl HasViewportPercentage for SpecifiedValue {
        fn has_viewport_percentage(&self) -> bool {
            match *self {
                SpecifiedValue::Repeat(ref length) => length.has_viewport_percentage(),
                _ => false
            }
        }
    }
    pub mod computed_value {
        use values::computed::LengthOrPercentage;
@ -1065,7 +1032,7 @@ ${helpers.single_keyword("animation-fill-mode",
        pub struct T(pub Option<LengthOrPercentage>);
    }
-    #[derive(Debug, Clone, PartialEq)]
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub enum SpecifiedValue {
        None,
@ -1175,9 +1142,8 @@ ${helpers.predefined_type("scroll-snap-coordinate",
    use values::specified::{LengthOrNumber, LengthOrPercentageOrNumber as LoPoNumber, Number};
    use style_traits::ToCss;
    use style_traits::values::Css;
    use values::HasViewportPercentage;
-    use std::fmt::{self, Display};
+    use std::fmt;
    pub mod computed_value {
        use app_units::Au;
@ -1253,7 +1219,7 @@ ${helpers.predefined_type("scroll-snap-coordinate",
    /// Multiple transform functions compose a transformation.
    ///
    /// Some transformations can be expressed by other more general functions.
-    #[derive(Clone, Debug, PartialEq)]
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub enum SpecifiedOperation {
        /// Represents a 2D 2x3 matrix.
@ -1328,41 +1294,6 @@ ${helpers.predefined_type("scroll-snap-coordinate",
        }
    }
    impl HasViewportPercentage for SpecifiedOperation {
        fn has_viewport_percentage(&self) -> bool {
            match *self {
                SpecifiedOperation::Translate(ref l1, None) |
                SpecifiedOperation::TranslateX(ref l1) |
                SpecifiedOperation::TranslateY(ref l1)  => {
                    l1.has_viewport_percentage()
                }
                SpecifiedOperation::TranslateZ(ref l1) => {
                    l1.has_viewport_percentage()
                }
                SpecifiedOperation::Translate(ref l1, Some(ref l2)) => {
                    l1.has_viewport_percentage() ||
                    l2.has_viewport_percentage()
                }
                SpecifiedOperation::Translate3D(ref l1, ref l2, ref l3) => {
                    l1.has_viewport_percentage() ||
                    l2.has_viewport_percentage() ||
                    l3.has_viewport_percentage()
                },
                SpecifiedOperation::Perspective(ref length) => length.has_viewport_percentage(),
                SpecifiedOperation::PrefixedMatrix{ ref e, ref f, .. } => {
                    e.has_viewport_percentage() ||
                    f.has_viewport_percentage()
                },
                SpecifiedOperation::PrefixedMatrix3D{ ref m41, ref m42, ref m43, .. } => {
                    m41.has_viewport_percentage() ||
                    m42.has_viewport_percentage() ||
                    m43.has_viewport_percentage()
                },
                _ => false
            }
        }
    }
    impl ToCss for SpecifiedOperation {
        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
            use self::SpecifiedOperation::*;
@ -1422,14 +1353,7 @@ ${helpers.predefined_type("scroll-snap-coordinate",
        }
    }
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            let &SpecifiedValue(ref specified_ops) = self;
            specified_ops.iter().any(|ref x| x.has_viewport_percentage())
        }
    }
    #[derive(Clone, Debug, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub struct SpecifiedValue(Vec<SpecifiedOperation>);
@ -2181,7 +2105,6 @@ ${helpers.single_keyword("transform-style",
    use app_units::Au;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::specified::{NoCalcLength, LengthOrPercentage, Percentage};
    pub mod computed_value {
@ -2223,15 +2146,7 @@ ${helpers.single_keyword("transform-style",
        }
    }
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            self.horizontal.has_viewport_percentage() ||
            self.vertical.has_viewport_percentage() ||
            self.depth.has_viewport_percentage()
        }
    }
    #[derive(Clone, Debug, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub struct SpecifiedValue {
        horizontal: LengthOrPercentage,
@ -2307,7 +2222,6 @@ ${helpers.single_keyword("transform-style",
                   spec="https://drafts.csswg.org/css-contain/#contain-property">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    impl ComputedValueAsSpecified for SpecifiedValue {}
@ -2460,7 +2374,6 @@ ${helpers.single_keyword("-moz-orient",
    use cssparser::serialize_identifier;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    impl ComputedValueAsSpecified for SpecifiedValue {}
@ -2533,7 +2446,6 @@ ${helpers.predefined_type("shape-outside", "basic_shape::ShapeWithShapeBox",
    use gecko_bindings::structs;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    impl ComputedValueAsSpecified for SpecifiedValue {}
--- a/servo/components/style/properties/longhand/color.mako.rs
+++ b/servo/components/style/properties/longhand/color.mako.rs
@ -14,7 +14,7 @@
    use cssparser::RGBA;
    use std::fmt;
    use style_traits::ToCss;
-    use values::specified::{AllowQuirks, Color, CSSColor, CSSRGBA};
+    use values::specified::{AllowQuirks, Color, CSSColor};
    impl ToComputedValue for SpecifiedValue {
        type ComputedValue = computed_value::T;
@ -122,6 +122,7 @@
        impl SystemColor {
            pub fn parse(input: &mut Parser) -> Result<Self, ()> {
                #[cfg(feature = "gecko")]
                use std::ascii::AsciiExt;
                static PARSE_ARRAY: &'static [(&'static str, SystemColor); ${len(system_colors)}] = &[
                    % for color in system_colors:
--- a/servo/components/style/properties/longhand/counters.mako.rs
+++ b/servo/components/style/properties/longhand/counters.mako.rs
@ -9,12 +9,11 @@
 <%helpers:longhand name="content" boxed="True" animation_value_type="none"
                   spec="https://drafts.csswg.org/css-content/#propdef-content">
    use cssparser::Token;
    use std::ascii::AsciiExt;
    use values::computed::ComputedValueAsSpecified;
    #[cfg(feature = "gecko")]
    use values::generics::CounterStyleOrNone;
    #[cfg(feature = "gecko")]
    use values::specified::url::SpecifiedUrl;
    use values::HasViewportPercentage;
    #[cfg(feature = "servo")]
    use super::list_style_type;
@ -29,6 +28,7 @@
        use cssparser;
        use std::fmt;
        use style_traits::ToCss;
        #[cfg(feature = "gecko")]
        use values::specified::url::SpecifiedUrl;
        #[cfg(feature = "servo")]
@ -256,11 +256,9 @@
                   spec="https://drafts.csswg.org/css-lists/#propdef-counter-increment">
    use std::fmt;
    use style_traits::ToCss;
-    use super::content;
+    use values::CustomIdent;
    use values::{HasViewportPercentage, CustomIdent};
-    use cssparser::{Token, serialize_identifier};
+    use cssparser::Token;
    use std::borrow::{Cow, ToOwned};
    #[derive(Debug, Clone, PartialEq)]
    pub struct SpecifiedValue(pub Vec<(CustomIdent, specified::Integer)>);
@ -278,7 +276,6 @@
            fn to_css<W>(&self, dest: &mut W) -> fmt::Result
                where W: fmt::Write,
            {
                use cssparser::serialize_identifier;
                if self.0.is_empty() {
                    return dest.write_str("none")
                }
@ -348,8 +345,6 @@
    }
    pub fn parse_common(context: &ParserContext, default_value: i32, input: &mut Parser) -> Result<SpecifiedValue, ()> {
        use std::ascii::AsciiExt;
        if input.try(|input| input.expect_ident_matching("none")).is_ok() {
            return Ok(SpecifiedValue(Vec::new()))
        }
--- a/servo/components/style/properties/longhand/effects.mako.rs
+++ b/servo/components/style/properties/longhand/effects.mako.rs
@ -18,10 +18,8 @@ ${helpers.predefined_type("opacity",
                          animation_value_type="IntermediateBoxShadowList"
                          extra_prefixes="webkit"
                          spec="https://drafts.csswg.org/css-backgrounds/#box-shadow">
    use cssparser;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    pub type SpecifiedValue = specified::Shadow;
@ -47,9 +45,6 @@ ${helpers.predefined_type("opacity",
    }
    pub mod computed_value {
        use app_units::Au;
        use std::fmt;
        use values::computed;
        use values::computed::Shadow;
        pub type T = Shadow;
@ -91,20 +86,16 @@ ${helpers.predefined_type("clip",
                   flags="CREATES_STACKING_CONTEXT FIXPOS_CB"
                   spec="https://drafts.fxtf.org/filters/#propdef-filter">
    //pub use self::computed_value::T as SpecifiedValue;
    use cssparser;
    use std::fmt;
-    use style_traits::{self, ToCss};
+    use style_traits::ToCss;
    use values::{CSSFloat, HasViewportPercentage};
-    use values::specified::{Angle, CSSColor, Length, Shadow};
+    use values::specified::{Angle, Length};
    #[cfg(feature = "gecko")]
    use values::specified::Shadow;
    #[cfg(feature = "gecko")]
    use values::specified::url::SpecifiedUrl;
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            self.0.iter().any(|ref x| x.has_viewport_percentage())
        }
    }
    #[derive(Debug, Clone, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub struct SpecifiedValue(pub Vec<SpecifiedFilter>);
@ -139,8 +130,10 @@ ${helpers.predefined_type("clip",
    pub mod computed_value {
        use app_units::Au;
        use values::CSSFloat;
-        use values::computed::{CSSColor, Shadow};
+        #[cfg(feature = "gecko")]
        use values::computed::Shadow;
        use values::computed::Angle;
        #[cfg(feature = "gecko")]
        use values::specified::url::SpecifiedUrl;
        #[derive(Clone, PartialEq, Debug)]
--- a/servo/components/style/properties/longhand/font.mako.rs
+++ b/servo/components/style/properties/longhand/font.mako.rs
@ -68,14 +68,11 @@
    use self::computed_value::{FontFamily, FamilyName};
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    no_viewport_percentage!(SpecifiedValue);
    pub mod computed_value {
        use cssparser::{CssStringWriter, Parser, serialize_identifier};
        use properties::longhands::system_font::SystemFont;
        use std::fmt::{self, Write};
        use Atom;
        use style_traits::ToCss;
@ -355,7 +352,6 @@ ${helpers.single_keyword_system("font-variant-caps",
                   spec="https://drafts.csswg.org/css-fonts/#propdef-font-weight">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use properties::longhands::system_font::SystemFont;
    no_viewport_percentage!(SpecifiedValue);
@ -449,7 +445,6 @@ ${helpers.single_keyword_system("font-variant-caps",
    }
    pub mod computed_value {
        use std::fmt;
        #[derive(PartialEq, Eq, Copy, Clone, Hash, Debug)]
        #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
        #[repr(u16)]
@ -557,7 +552,7 @@ ${helpers.single_keyword_system("font-variant-caps",
    use std::fmt;
    use style_traits::ToCss;
    use values::{FONT_MEDIUM_PX, HasViewportPercentage};
-    use values::specified::{AllowQuirks, FontRelativeLength, LengthOrPercentage, Length};
+    use values::specified::{AllowQuirks, FontRelativeLength, LengthOrPercentage};
    use values::specified::{NoCalcLength, Percentage};
    use values::specified::length::FontBaseSize;
@ -694,8 +689,7 @@ ${helpers.single_keyword_system("font-variant-caps",
            type ComputedValue = Au;
            #[inline]
            fn to_computed_value(&self, cx: &Context) -> computed_value::T {
-                use gecko_bindings::bindings::Gecko_GetBaseSize;
+                use gecko_bindings::structs::nsIAtom;
                use gecko_bindings::structs::{self, nsIAtom};
                use values::specified::length::au_to_int_px;
                // Data from nsRuleNode.cpp in Gecko
                // Mapping from base size and HTML size to pixels
@ -977,7 +971,6 @@ ${helpers.single_keyword_system("font-variant-caps",
    use properties::longhands::system_font::SystemFont;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
@ -1119,7 +1112,6 @@ ${helpers.single_keyword_system("font-variant-caps",
                   spec="https://drafts.csswg.org/css-fonts/#propdef-font-synthesis">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    impl ComputedValueAsSpecified for SpecifiedValue {}
@ -1203,7 +1195,6 @@ ${helpers.single_keyword_system("font-kerning",
    use properties::longhands::system_font::SystemFont;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
@ -1339,7 +1330,6 @@ macro_rules! exclusive_value {
    use properties::longhands::system_font::SystemFont;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
@ -1480,7 +1470,6 @@ macro_rules! exclusive_value {
    use properties::longhands::system_font::SystemFont;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
@ -1631,7 +1620,6 @@ macro_rules! exclusive_value {
    use properties::longhands::system_font::SystemFont;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
@ -1784,8 +1772,6 @@ ${helpers.single_keyword_system("font-variant-position",
    use properties::longhands::system_font::SystemFont;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    #[derive(Debug, Clone, PartialEq)]
    pub enum SpecifiedValue {
@ -1868,8 +1854,6 @@ ${helpers.single_keyword_system("font-variant-position",
            /// <string> [ on | off | <integer> ]
            fn parse(_context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
                use std::io::Cursor;
                use std::str;
                use std::ops::Deref;
                use byteorder::{ReadBytesExt, BigEndian};
                let tag = try!(input.expect_string());
@ -1928,7 +1912,6 @@ ${helpers.single_keyword_system("font-variant-position",
    use std::fmt;
    use style_traits::ToCss;
    use byteorder::{BigEndian, ByteOrder};
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    #[derive(Debug, Clone, PartialEq, Eq)]
@ -2063,7 +2046,6 @@ ${helpers.single_keyword_system("font-variant-position",
 <%helpers:longhand name="-x-lang" products="gecko" animation_value_type="none" internal="True"
                   spec="Internal (not web-exposed)">
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    pub use self::computed_value::T as SpecifiedValue;
@ -2102,12 +2084,10 @@ ${helpers.single_keyword_system("font-variant-position",
                   predefined_type="Number" gecko_ffi_name="mScriptSizeMultiplier"
                   spec="Internal (not web-exposed)"
                   internal="True" disable_when_testing="True">
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    pub use self::computed_value::T as SpecifiedValue;
    impl ComputedValueAsSpecified for SpecifiedValue {}
    no_viewport_percentage!(SpecifiedValue);
    pub mod computed_value {
        pub type T = f32;
@ -2130,7 +2110,6 @@ ${helpers.single_keyword_system("font-variant-position",
                   internal="True" disable_when_testing="True" need_clone="True">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
@ -2230,11 +2209,9 @@ ${helpers.single_keyword("-moz-math-variant",
    use gecko_bindings::structs::NS_MATHML_DEFAULT_SCRIPT_MIN_SIZE_PT;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    use values::specified::length::{AU_PER_PT, FontBaseSize, NoCalcLength};
-    #[derive(Clone, PartialEq, Debug)]
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
    pub struct SpecifiedValue(pub NoCalcLength);
    pub mod computed_value {
@ -2272,12 +2249,6 @@ ${helpers.single_keyword("-moz-math-variant",
        }
    }
    impl HasViewportPercentage for SpecifiedValue {
        fn has_viewport_percentage(&self) -> bool {
            self.0.has_viewport_percentage()
        }
    }
    #[inline]
    pub fn get_initial_value() -> computed_value::T {
        Au((NS_MATHML_DEFAULT_SCRIPT_MIN_SIZE_PT as f32 * AU_PER_PT) as i32)
--- a/servo/components/style/properties/longhand/inherited_box.mako.rs
+++ b/servo/components/style/properties/longhand/inherited_box.mako.rs
@ -68,7 +68,6 @@ ${helpers.single_keyword("image-rendering",
    use style_traits::ToCss;
    use values::specified::Angle;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    use std::f32::consts::PI;
@ -207,7 +206,6 @@ ${helpers.single_keyword("image-rendering",
    use std::fmt;
    use style_traits::ToCss;
    use values::computed::ComputedValueAsSpecified;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
--- a/servo/components/style/properties/longhand/inherited_svg.mako.rs
+++ b/servo/components/style/properties/longhand/inherited_svg.mako.rs
@ -144,7 +144,6 @@ ${helpers.predefined_type("marker-end", "UrlOrNone", "Either::Second(None_)",
    use values::computed::ComputedValueAsSpecified;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    pub const NORMAL: u8 = 0;
    pub const FILL: u8 = 1;
--- a/servo/components/style/properties/longhand/inherited_table.mako.rs
+++ b/servo/components/style/properties/longhand/inherited_table.mako.rs
@ -25,7 +25,6 @@ ${helpers.single_keyword("caption-side", "top bottom",
    use app_units::Au;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::specified::{AllowQuirks, Length};
    pub mod computed_value {
@ -65,14 +64,7 @@ ${helpers.single_keyword("caption-side", "top bottom",
        }
    }
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            self.horizontal.has_viewport_percentage() ||
            self.vertical.as_ref().map_or(false, |v| v.has_viewport_percentage())
        }
    }
    #[derive(Clone, Debug, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub struct SpecifiedValue {
        pub horizontal: Length,
--- a/servo/components/style/properties/longhand/inherited_text.mako.rs
+++ b/servo/components/style/properties/longhand/inherited_text.mako.rs
@ -10,18 +10,8 @@
                   spec="https://drafts.csswg.org/css2/visudet.html#propdef-line-height">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            match *self {
                SpecifiedValue::LengthOrPercentage(ref length) => length.has_viewport_percentage(),
                _ => false
            }
        }
    }
    #[derive(Debug, Clone, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub enum SpecifiedValue {
        Normal,
@ -75,7 +65,6 @@
    }
    pub mod computed_value {
        use app_units::Au;
        use std::fmt;
        use values::CSSFloat;
        #[derive(PartialEq, Copy, Clone, Debug)]
        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
@ -212,7 +201,6 @@ ${helpers.single_keyword("word-break",
                                  gecko_enum_prefix="StyleTextJustify"
                                  animation_value_type="none"
                                  spec="https://drafts.csswg.org/css-text/#propdef-text-justify">
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    impl ToComputedValue for SpecifiedValue {
@ -256,8 +244,6 @@ ${helpers.single_keyword("text-align-last",
 // TODO make this a shorthand and implement text-align-last/text-align-all
 <%helpers:longhand name="text-align" animation_value_type="none" need_clone="True"
                   spec="https://drafts.csswg.org/css-text/#propdef-text-align">
    use values::computed::ComputedValueAsSpecified;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
    pub mod computed_value {
        use style_traits::ToCss;
@ -400,6 +386,7 @@ ${helpers.single_keyword("text-align-last",
            }
        }
    % else:
        use values::computed::ComputedValueAsSpecified;
        impl ComputedValueAsSpecified for SpecifiedValue {}
        pub use self::computed_value::T as SpecifiedValue;
        pub fn parse(_context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
@ -412,19 +399,9 @@ ${helpers.single_keyword("text-align-last",
                   spec="https://drafts.csswg.org/css-text/#propdef-letter-spacing">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::specified::AllowQuirks;
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            match *self {
                SpecifiedValue::Specified(ref length) => length.has_viewport_percentage(),
                _ => false
            }
        }
    }
    #[derive(Debug, Clone, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub enum SpecifiedValue {
        Normal,
@ -498,19 +475,9 @@ ${helpers.single_keyword("text-align-last",
                   spec="https://drafts.csswg.org/css-text/#propdef-word-spacing">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::specified::AllowQuirks;
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            match *self {
                SpecifiedValue::Specified(ref length) => length.has_viewport_percentage(),
                _ => false
            }
        }
    }
    #[derive(Debug, Clone, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub enum SpecifiedValue {
        Normal,
@ -588,7 +555,6 @@ ${helpers.single_keyword("text-align-last",
    use cssparser::RGBA;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    impl ComputedValueAsSpecified for SpecifiedValue {}
@ -674,7 +640,6 @@ ${helpers.single_keyword("text-align-last",
                                  animation_value_type="none"
                                  spec="https://drafts.csswg.org/css-text/#propdef-white-space">
    use values::computed::ComputedValueAsSpecified;
    use values::HasViewportPercentage;
    impl ComputedValueAsSpecified for SpecifiedValue {}
    no_viewport_percentage!(SpecifiedValue);
@ -720,28 +685,12 @@ ${helpers.single_keyword("text-align-last",
    use std::fmt;
    use style_traits::ToCss;
    use values::specified::Shadow;
    use values::HasViewportPercentage;
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            let &SpecifiedValue(ref vec) = self;
            vec.iter().any(|ref x| x.has_viewport_percentage())
        }
    }
    #[derive(Clone, PartialEq, Debug)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub struct SpecifiedValue(Vec<SpecifiedTextShadow>);
-    impl HasViewportPercentage for SpecifiedTextShadow {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            self.offset_x.has_viewport_percentage() ||
            self.offset_y.has_viewport_percentage() ||
            self.blur_radius.has_viewport_percentage()
        }
    }
    #[derive(Clone, PartialEq, Debug)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub struct SpecifiedTextShadow {
        pub offset_x: specified::Length,
@ -891,7 +840,6 @@ ${helpers.single_keyword("text-align-last",
    use std::fmt;
    use style_traits::ToCss;
    use unicode_segmentation::UnicodeSegmentation;
    use values::HasViewportPercentage;
    no_viewport_percentage!(SpecifiedValue);
@ -1097,7 +1045,6 @@ ${helpers.single_keyword("text-align-last",
                   spec="https://drafts.csswg.org/css-text-decor/#propdef-text-emphasis-position">
    use std::fmt;
    use values::computed::ComputedValueAsSpecified;
    use values::HasViewportPercentage;
    use style_traits::ToCss;
    define_css_keyword_enum!(HorizontalWritingModeValue:
--- a/servo/components/style/properties/longhand/list.mako.rs
+++ b/servo/components/style/properties/longhand/list.mako.rs
@ -36,7 +36,6 @@ ${helpers.single_keyword("list-style-position", "outside inside", animation_valu
        use std::fmt;
        use style_traits::ToCss;
        use values::CustomIdent;
        use values::HasViewportPercentage;
        use values::computed::ComputedValueAsSpecified;
        use values::generics::CounterStyleOrNone;
@ -105,7 +104,6 @@ ${helpers.single_keyword("list-style-position", "outside inside", animation_valu
                   boxed="${product == 'gecko'}"
                   spec="https://drafts.csswg.org/css-lists/#propdef-list-style-image">
    use std::fmt;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    use values::specified::UrlOrNone;
    pub use self::computed_value::T as SpecifiedValue;
@ -158,7 +156,6 @@ ${helpers.single_keyword("list-style-position", "outside inside", animation_valu
    use std::fmt;
    use style_traits::ToCss;
    use values::computed::ComputedValueAsSpecified;
    use values::HasViewportPercentage;
    pub use self::computed_value::T as SpecifiedValue;
--- a/servo/components/style/properties/longhand/outline.mako.rs
+++ b/servo/components/style/properties/longhand/outline.mako.rs
@ -17,11 +17,7 @@ ${helpers.predefined_type("outline-color", "CSSColor", "computed::CSSColor::Curr
 <%helpers:longhand name="outline-style" need_clone="True" animation_value_type="none"
                   spec="https://drafts.csswg.org/css-ui/#propdef-outline-style">
    use std::fmt;
    use style_traits::ToCss;
    use values::specified::BorderStyle;
    use values::computed::ComputedValueAsSpecified;
    pub type SpecifiedValue = Either<Auto, BorderStyle>;
@ -66,10 +62,8 @@ ${helpers.predefined_type("outline-color", "CSSColor", "computed::CSSColor::Curr
 <%helpers:longhand name="outline-width" animation_value_type="ComputedValue"
                   spec="https://drafts.csswg.org/css-ui/#propdef-outline-width">
    use app_units::Au;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    impl ToCss for SpecifiedValue {
        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
@ -81,16 +75,10 @@ ${helpers.predefined_type("outline-color", "CSSColor", "computed::CSSColor::Curr
        specified::parse_border_width(context, input).map(SpecifiedValue)
    }
-    impl HasViewportPercentage for SpecifiedValue {
+    #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
        fn has_viewport_percentage(&self) -> bool {
            let &SpecifiedValue(ref length) = self;
            length.has_viewport_percentage()
        }
    }
    #[derive(Debug, Clone, PartialEq)]
    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
    pub struct SpecifiedValue(pub specified::Length);
    pub mod computed_value {
        use app_units::Au;
        pub type T = Au;
--- a/servo/components/style/properties/longhand/pointing.mako.rs
+++ b/servo/components/style/properties/longhand/pointing.mako.rs
@ -9,8 +9,8 @@
 <%helpers:longhand name="cursor" boxed="${product == 'gecko'}" animation_value_type="none"
  spec="https://drafts.csswg.org/css-ui/#cursor">
    pub use self::computed_value::T as SpecifiedValue;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    #[cfg(feature = "gecko")]
    use values::specified::url::SpecifiedUrl;
    impl ComputedValueAsSpecified for SpecifiedValue {}
@ -20,6 +20,7 @@
        use std::fmt;
        use style_traits::cursor::Cursor;
        use style_traits::ToCss;
        #[cfg(feature = "gecko")]
        use values::specified::url::SpecifiedUrl;
        #[derive(Clone, PartialEq, Copy, Debug)]
--- a/servo/components/style/properties/longhand/position.mako.rs
+++ b/servo/components/style/properties/longhand/position.mako.rs
@ -178,20 +178,16 @@ ${helpers.predefined_type("flex-basis",
                use std::fmt;
                use style_traits::ToCss;
-                use values::HasViewportPercentage;
+                % if not logical:
-                use values::specified::{AllowQuirks, ${MinMax}Length};
+                    use values::specified::AllowQuirks;
-
+                % endif
-                impl HasViewportPercentage for SpecifiedValue {
+                use values::specified::${MinMax}Length;
                    fn has_viewport_percentage(&self) -> bool {
                        self.0.has_viewport_percentage()
                    }
                }
                pub mod computed_value {
                    pub type T = ::values::computed::${MinMax}Length;
                }
-                #[derive(PartialEq, Clone, Debug)]
+                #[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
                #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
                pub struct SpecifiedValue(${MinMax}Length);
@ -225,7 +221,9 @@ ${helpers.predefined_type("flex-basis",
                    type ComputedValue = computed_value::T;
                    #[inline]
                    fn to_computed_value(&self, context: &Context) -> computed_value::T {
-                        use values::computed::${MinMax}Length;
+                        % if not logical or "block" in size:
                            use values::computed::${MinMax}Length;
                        % endif
                        let computed = self.0.to_computed_value(context);
                        // filter out keyword values in the block direction
@ -338,7 +336,6 @@ ${helpers.predefined_type("object-position",
        animation_value_type="none">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    pub type SpecifiedValue = computed_value::T;
@ -430,8 +427,6 @@ ${helpers.predefined_type("object-position",
    use std::ops::Range;
    use str::HTML_SPACE_CHARACTERS;
    use style_traits::ToCss;
    use style_traits::values::Css;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    pub mod computed_value {
--- a/servo/components/style/properties/longhand/svg.mako.rs
+++ b/servo/components/style/properties/longhand/svg.mako.rs
@ -77,7 +77,6 @@ ${helpers.single_keyword("mask-mode",
    pub use properties::longhands::background_repeat::single_value::SpecifiedValue;
    pub use properties::longhands::background_repeat::single_value::computed_value;
    pub use properties::longhands::background_repeat::single_value::RepeatKeyword;
    use properties::longhands::background_repeat::single_value;
    #[inline]
    pub fn get_initial_value() -> computed_value::T {
--- a/servo/components/style/properties/longhand/table.mako.rs
+++ b/servo/components/style/properties/longhand/table.mako.rs
@ -14,7 +14,6 @@ ${helpers.single_keyword("table-layout", "auto fixed",
                   spec="Internal-only (for `<col span>` pres attr)"
                   animation_value_type="none"
                   internal="True">
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    impl ComputedValueAsSpecified for SpecifiedValue {}
--- a/servo/components/style/properties/longhand/text.mako.rs
+++ b/servo/components/style/properties/longhand/text.mako.rs
@ -16,7 +16,6 @@
                   spec="https://drafts.csswg.org/css-ui/#propdef-text-overflow">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    use cssparser;
@ -107,7 +106,6 @@ ${helpers.single_keyword("unicode-bidi",
                   spec="https://drafts.csswg.org/css-text-decor/#propdef-text-decoration-line">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    impl ComputedValueAsSpecified for SpecifiedValue {}
@ -237,7 +235,6 @@ ${helpers.predefined_type(
                   spec="https://drafts.csswg.org/css-inline/#sizing-drop-initials">
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    use values::specified::{Number, Integer};
--- a/servo/components/style/properties/longhand/ui.mako.rs
+++ b/servo/components/style/properties/longhand/ui.mako.rs
@ -35,10 +35,8 @@ ${helpers.single_keyword("-moz-window-dragging", "default drag no-drag", product
                   products="gecko"
                   animation_value_type="none"
                   spec="None (Nonstandard Firefox-only property)">
    use cssparser::Token;
    use std::fmt;
    use style_traits::ToCss;
    use values::HasViewportPercentage;
    use values::computed::ComputedValueAsSpecified;
    no_viewport_percentage!(SpecifiedValue);
--- a/servo/components/style/values/computed/mod.rs
+++ b/servo/components/style/values/computed/mod.rs
@ -175,7 +175,7 @@ impl<T> ToComputedValue for T
 }
 /// A computed `<angle>` value.
-#[derive(Clone, PartialEq, PartialOrd, Copy, Debug)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq, PartialOrd)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
 pub enum Angle {
    /// An angle with degree unit
--- a/servo/components/style/values/generics/image.rs
+++ b/servo/components/style/values/generics/image.rs
@ -32,7 +32,7 @@ pub enum Image<Gradient, ImageRect> {
 /// A CSS gradient.
 /// https://drafts.csswg.org/css-images/#gradients
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct Gradient<LineDirection, Length, LengthOrPercentage, Position, Color> {
    /// Gradients can be linear or radial.
@ -45,7 +45,7 @@ pub struct Gradient<LineDirection, Length, LengthOrPercentage, Position, Color>
    pub compat_mode: CompatMode,
 }
-#[derive(Clone, Copy, PartialEq, Debug)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 /// Whether we used the modern notation or the compatibility `-webkit` prefix.
 pub enum CompatMode {
@ -56,7 +56,7 @@ pub enum CompatMode {
 }
 /// A gradient kind.
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum GradientKind<LineDirection, Length, LengthOrPercentage, Position> {
    /// A linear gradient.
@ -66,7 +66,7 @@ pub enum GradientKind<LineDirection, Length, LengthOrPercentage, Position> {
 }
 /// A radial gradient's ending shape.
-#[derive(Clone, Copy, PartialEq, Debug)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum EndingShape<Length, LengthOrPercentage> {
    /// A circular gradient.
@ -76,7 +76,7 @@ pub enum EndingShape<Length, LengthOrPercentage> {
 }
 /// A circle shape.
-#[derive(Clone, Copy, PartialEq, Debug)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum Circle<Length> {
    /// A circle radius.
@ -86,7 +86,7 @@ pub enum Circle<Length> {
 }
 /// An ellipse shape.
-#[derive(Clone, Copy, PartialEq, Debug)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum Ellipse<LengthOrPercentage> {
    /// An ellipse pair of radii.
@ -104,10 +104,11 @@ define_css_keyword_enum!(ShapeExtent:
    "contain" => Contain,
    "cover" => Cover
 );
 no_viewport_percentage!(ShapeExtent);
 /// A gradient item.
 /// https://drafts.csswg.org/css-images-4/#color-stop-syntax
-#[derive(Clone, Copy, PartialEq, Debug)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum GradientItem<Color, LengthOrPercentage> {
    /// A color stop.
@ -118,7 +119,7 @@ pub enum GradientItem<Color, LengthOrPercentage> {
 /// A color stop.
 /// https://drafts.csswg.org/css-images/#typedef-color-stop-list
-#[derive(Clone, Copy, PartialEq)]
+#[derive(Clone, Copy, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct ColorStop<Color, LengthOrPercentage> {
    /// The color of this stop.
@ -281,17 +282,6 @@ impl<D, L, LoP, P, C> ToCss for Gradient<D, L, LoP, P, C>
    }
 }
 impl<D, L, LoP, P, C> HasViewportPercentage for Gradient<D, L, LoP, P, C>
    where L: HasViewportPercentage,
          LoP: HasViewportPercentage,
          P: HasViewportPercentage,
 {
    fn has_viewport_percentage(&self) -> bool {
        self.kind.has_viewport_percentage() ||
        self.items.iter().any(|i| i.has_viewport_percentage())
    }
 }
 impl<D, L, LoP, P, C> ToComputedValue for Gradient<D, L, LoP, P, C>
    where D: ToComputedValue,
          L: ToComputedValue,
@ -333,21 +323,6 @@ impl<D, L, LoP, P> GradientKind<D, L, LoP, P> {
    }
 }
 impl<D, L, LoP, P> HasViewportPercentage for GradientKind<D, L, LoP, P>
    where L: HasViewportPercentage,
          LoP: HasViewportPercentage,
          P: HasViewportPercentage
 {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            GradientKind::Linear(_) => false,
            GradientKind::Radial(ref shape, ref position) => {
                shape.has_viewport_percentage() || position.has_viewport_percentage()
            },
        }
    }
 }
 impl<D, L, LoP, P> ToComputedValue for GradientKind<D, L, LoP, P>
    where D: ToComputedValue,
          L: ToComputedValue,
@ -423,22 +398,6 @@ impl<L, LoP> ToCss for EndingShape<L, LoP>
    }
 }
 impl<L, LoP> HasViewportPercentage for EndingShape<L, LoP>
    where L: HasViewportPercentage, LoP: HasViewportPercentage,
 {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            EndingShape::Circle(Circle::Radius(ref length)) => {
                length.has_viewport_percentage()
            },
            EndingShape::Ellipse(Ellipse::Radii(ref x, ref y)) => {
                x.has_viewport_percentage() || y.has_viewport_percentage()
            },
            _ => false,
        }
    }
 }
 impl<L, LoP> ToComputedValue for EndingShape<L, LoP>
    where L: ToComputedValue, LoP: ToComputedValue,
 {
@ -497,17 +456,6 @@ impl<C, L> ToCss for GradientItem<C, L>
    }
 }
 impl<C, L> HasViewportPercentage for GradientItem<C, L>
    where L: HasViewportPercentage,
 {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            GradientItem::ColorStop(ref stop) => stop.has_viewport_percentage(),
            GradientItem::InterpolationHint(ref hint) => hint.has_viewport_percentage(),
        }
    }
 }
 impl<C, L> ToComputedValue for GradientItem<C, L>
    where C: ToComputedValue, L: ToComputedValue,
 {
@ -562,14 +510,6 @@ impl<C, L> ToCss for ColorStop<C, L>
    }
 }
 impl<C, L> HasViewportPercentage for ColorStop<C, L>
    where L: HasViewportPercentage,
 {
    fn has_viewport_percentage(&self) -> bool {
        self.position.as_ref().map_or(false, HasViewportPercentage::has_viewport_percentage)
    }
 }
 impl<C, L> ToComputedValue for ColorStop<C, L>
    where C: ToComputedValue, L: ToComputedValue,
 {
--- a/servo/components/style/values/generics/position.rs
+++ b/servo/components/style/values/generics/position.rs
@ -5,10 +5,9 @@
 //! Generic types for CSS handling of specified and computed values of
 //! [`position`](https://drafts.csswg.org/css-backgrounds-3/#position)
 use values::HasViewportPercentage;
 use values::computed::{Context, ToComputedValue};
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 /// A generic type for representing a CSS [position](https://drafts.csswg.org/css-values/#position).
 pub struct Position<H, V> {
@ -28,13 +27,6 @@ impl<H, V> Position<H, V> {
    }
 }
 impl<H: HasViewportPercentage, V: HasViewportPercentage> HasViewportPercentage for Position<H, V> {
    #[inline]
    fn has_viewport_percentage(&self) -> bool {
        self.horizontal.has_viewport_percentage() || self.vertical.has_viewport_percentage()
    }
 }
 impl<H: ToComputedValue, V: ToComputedValue> ToComputedValue for Position<H, V> {
    type ComputedValue = Position<<H as ToComputedValue>::ComputedValue,
                                  <V as ToComputedValue>::ComputedValue>;
--- a/servo/components/style/values/mod.rs
+++ b/servo/components/style/values/mod.rs
@ -16,6 +16,7 @@ use std::borrow::Cow;
 use std::fmt::{self, Debug};
 use std::hash;
 use style_traits::ToCss;
 pub use style_traits::HasViewportPercentage;
 pub mod computed;
 pub mod generics;
@ -30,24 +31,11 @@ pub type CSSInteger = i32;
 /// The default font size.
 pub const FONT_MEDIUM_PX: i32 = 16;
 /// A trait used to query whether this value has viewport units.
 pub trait HasViewportPercentage {
    /// Returns true if this value has viewport units.
    fn has_viewport_percentage(&self) -> bool;
 }
 impl<T: HasViewportPercentage> HasViewportPercentage for Box<T> {
    #[inline]
    fn has_viewport_percentage(&self) -> bool {
        (**self).has_viewport_percentage()
    }
 }
 define_keyword_type!(None_, "none");
 define_keyword_type!(Auto, "auto");
 define_keyword_type!(Normal, "normal");
-#[derive(Clone, PartialEq, Copy)]
+#[derive(Clone, Copy, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 /// A struct representing one of two kinds of values.
 pub enum Either<A, B> {
@ -75,15 +63,6 @@ impl<A: ToCss, B: ToCss> ToCss for Either<A, B> {
    }
 }
 impl<A: HasViewportPercentage, B: HasViewportPercentage> HasViewportPercentage for Either<A, B> {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            Either::First(ref v) => v.has_viewport_percentage(),
            Either::Second(ref v) => v.has_viewport_percentage(),
        }
    }
 }
 impl<A: Parse, B: Parse> Parse for Either<A, B> {
    fn parse(context: &ParserContext, input: &mut Parser) -> Result<Either<A, B>, ()> {
        if let Ok(v) = input.try(|i| A::parse(context, i)) {
@ -209,3 +188,4 @@ define_css_keyword_enum!(ExtremumLength:
                         "-moz-min-content" => MinContent,
                         "-moz-fit-content" => FitContent,
                         "-moz-available" => FillAvailable);
 no_viewport_percentage!(ExtremumLength);
--- a/servo/components/style/values/specified/grid.rs
+++ b/servo/components/style/values/specified/grid.rs
@ -221,7 +221,7 @@ impl<L: ToComputedValue> ToComputedValue for TrackBreadth<L> {
    }
 }
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 /// 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>`
@ -321,17 +321,6 @@ impl<L: ToCss> ToCss for TrackSize<L> {
    }
 }
 impl HasViewportPercentage for TrackSize<LengthOrPercentage> {
    #[inline]
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            TrackSize::Breadth(ref b) => b.has_viewport_percentage(),
            TrackSize::MinMax(ref inf_b, ref b) => inf_b.has_viewport_percentage() || b.has_viewport_percentage(),
            TrackSize::FitContent(ref lop) => lop.has_viewport_percentage(),
        }
    }
 }
 impl<L: ToComputedValue> ToComputedValue for TrackSize<L> {
    type ComputedValue = TrackSize<L::ComputedValue>;
--- a/servo/components/style/values/specified/image.rs
+++ b/servo/components/style/values/specified/image.rs
@ -54,7 +54,7 @@ pub type GradientKind = GenericGradientKind<
 >;
 /// A specified gradient line direction.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum LineDirection {
    /// An angular direction.
--- a/servo/components/style/values/specified/length.rs
+++ b/servo/components/style/values/specified/length.rs
@ -531,7 +531,7 @@ impl NoCalcLength {
 /// This is commonly used for the `<length>` values.
 ///
 /// https://drafts.csswg.org/css-values/#lengths
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum Length {
    /// The internal length type that cannot parse `calc`
@ -549,15 +549,6 @@ impl From<NoCalcLength> for Length {
    }
 }
 impl HasViewportPercentage for Length {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            Length::NoCalc(ref inner) => inner.has_viewport_percentage(),
            Length::Calc(ref calc) => calc.has_viewport_percentage(),
        }
    }
 }
 impl ToCss for Length {
    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
        match *self {
@ -713,7 +704,7 @@ impl<T: Parse> Either<Length, T> {
 /// As of today, only `-moz-image-rect` supports percentages without length.
 /// This is not a regression, and that's a non-standard extension anyway, so I'm
 /// not implementing it for now.
-#[derive(Clone, PartialEq, Copy, Debug)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct Percentage(pub CSSFloat);
@ -754,7 +745,7 @@ impl Parse for Percentage {
 impl ComputedValueAsSpecified for Percentage {}
 /// A length or a percentage value.
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
 pub enum LengthOrPercentage {
@ -786,16 +777,6 @@ impl From<Percentage> for LengthOrPercentage {
    }
 }
 impl HasViewportPercentage for LengthOrPercentage {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            LengthOrPercentage::Length(ref length) => length.has_viewport_percentage(),
            LengthOrPercentage::Calc(ref calc) => calc.has_viewport_percentage(),
            _ => false
        }
    }
 }
 impl ToCss for LengthOrPercentage {
    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
        match *self {
@ -914,7 +895,7 @@ impl LengthOrPercentage {
 }
 /// Either a `<length>`, a `<percentage>`, or the `auto` keyword.
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
 pub enum LengthOrPercentageOrAuto {
@ -938,16 +919,6 @@ impl From<Percentage> for LengthOrPercentageOrAuto {
    }
 }
 impl HasViewportPercentage for LengthOrPercentageOrAuto {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            LengthOrPercentageOrAuto::Length(ref length) => length.has_viewport_percentage(),
            LengthOrPercentageOrAuto::Calc(ref calc) => calc.has_viewport_percentage(),
            _ => false
        }
    }
 }
 impl ToCss for LengthOrPercentageOrAuto {
    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
        match *self {
@ -1036,7 +1007,7 @@ impl LengthOrPercentageOrAuto {
 }
 /// Either a `<length>`, a `<percentage>`, or the `none` keyword.
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
 pub enum LengthOrPercentageOrNone {
@ -1046,16 +1017,6 @@ pub enum LengthOrPercentageOrNone {
    None,
 }
 impl HasViewportPercentage for LengthOrPercentageOrNone {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            LengthOrPercentageOrNone::Length(ref length) => length.has_viewport_percentage(),
            LengthOrPercentageOrNone::Calc(ref calc) => calc.has_viewport_percentage(),
            _ => false
        }
    }
 }
 impl ToCss for LengthOrPercentageOrNone {
    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
        match *self {
@ -1133,7 +1094,7 @@ pub type LengthOrAuto = Either<Length, Auto>;
 /// Either a `<length>` or a `<percentage>` or the `auto` keyword or the
 /// `content` keyword.
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum LengthOrPercentageOrAutoOrContent {
    /// A `<length>`.
@ -1185,16 +1146,6 @@ impl LengthOrPercentageOrAutoOrContent {
    }
 }
 impl HasViewportPercentage for LengthOrPercentageOrAutoOrContent {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            LengthOrPercentageOrAutoOrContent::Length(ref length) => length.has_viewport_percentage(),
            LengthOrPercentageOrAutoOrContent::Calc(ref calc) => calc.has_viewport_percentage(),
            _ => false
        }
    }
 }
 impl ToCss for LengthOrPercentageOrAutoOrContent {
    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
        match *self {
@ -1227,7 +1178,7 @@ impl LengthOrNumber {
 /// A value suitable for a `min-width` or `min-height` property.
 /// Unlike `max-width` or `max-height` properties, a MinLength can be
 /// `auto`, and cannot be `none`.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
 pub enum MinLength {
@ -1236,15 +1187,6 @@ pub enum MinLength {
    ExtremumLength(ExtremumLength),
 }
 impl HasViewportPercentage for MinLength {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            MinLength::LengthOrPercentage(ref lop) => lop.has_viewport_percentage(),
            _ => false
        }
    }
 }
 impl ToCss for MinLength {
    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
        match *self {
@ -1277,7 +1219,7 @@ impl MinLength {
 }
 /// A value suitable for a `max-width` or `max-height` property.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
 pub enum MaxLength {
@ -1286,14 +1228,6 @@ pub enum MaxLength {
    ExtremumLength(ExtremumLength),
 }
 impl HasViewportPercentage for MaxLength {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            MaxLength::LengthOrPercentage(ref lop) => lop.has_viewport_percentage(),
            _ => false
        }
    }
 }
 impl ToCss for MaxLength {
    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
--- a/servo/components/style/values/specified/mod.rs
+++ b/servo/components/style/values/specified/mod.rs
@ -21,7 +21,7 @@ use std::fmt;
 use std::io::Write;
 use style_traits::ToCss;
 use style_traits::values::specified::AllowedNumericType;
-use super::{Auto, CSSFloat, CSSInteger, HasViewportPercentage, Either, None_};
+use super::{Auto, CSSFloat, CSSInteger, Either, None_};
 use super::computed::{self, Context};
 use super::computed::{Shadow as ComputedShadow, ToComputedValue};
 use super::generics::BorderRadiusSize as GenericBorderRadiusSize;
@ -76,8 +76,6 @@ impl ComputedValueAsSpecified for SpecifiedUrl {}
 no_viewport_percentage!(SpecifiedUrl);
 }
 no_viewport_percentage!(i32);  // For PropertyDeclaration::Order
 #[derive(Clone, PartialEq, Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
@ -289,7 +287,7 @@ impl Parse for BorderRadiusSize {
    }
 }
-#[derive(Clone, PartialEq, Copy, Debug)]
+#[derive(Clone, Copy, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
 /// An angle consisting of a value and a unit.
 ///
@ -455,7 +453,7 @@ pub fn parse_border_width(context: &ParserContext, input: &mut Parser) -> Result
    })
 }
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
 pub enum BorderWidth {
@ -507,15 +505,6 @@ impl ToCss for BorderWidth {
    }
 }
 impl HasViewportPercentage for BorderWidth {
    fn has_viewport_percentage(&self) -> bool {
        match *self {
            BorderWidth::Thin | BorderWidth::Medium | BorderWidth::Thick => false,
            BorderWidth::Width(ref length) => length.has_viewport_percentage()
        }
    }
 }
 impl ToComputedValue for BorderWidth {
    type ComputedValue = Au;
@ -950,7 +939,7 @@ pub type TrackList = GenericTrackList<TrackSizeOrRepeat>;
 /// `<track-list> | none`
 pub type TrackListOrNone = Either<TrackList, None_>;
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
 pub struct Shadow {
@ -962,15 +951,6 @@ pub struct Shadow {
    pub inset: bool,
 }
 impl HasViewportPercentage for Shadow {
    fn has_viewport_percentage(&self) -> bool {
        self.offset_x.has_viewport_percentage() ||
        self.offset_y.has_viewport_percentage() ||
        self.blur_radius.has_viewport_percentage() ||
        self.spread_radius.has_viewport_percentage()
    }
 }
 impl ToComputedValue for Shadow {
    type ComputedValue = ComputedShadow;
@ -1230,16 +1210,7 @@ impl LengthOrPercentageOrNumber {
    }
 }
-impl HasViewportPercentage for ClipRect {
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
    fn has_viewport_percentage(&self) -> bool {
        self.top.as_ref().map_or(false, |x| x.has_viewport_percentage()) ||
        self.right.as_ref().map_or(false, |x| x.has_viewport_percentage()) ||
        self.bottom.as_ref().map_or(false, |x| x.has_viewport_percentage()) ||
        self.left.as_ref().map_or(false, |x| x.has_viewport_percentage())
    }
 }
 #[derive(Clone, Debug, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 /// rect(<top>, <left>, <bottom>, <right>) used by clip and image-region
 pub struct ClipRect {
--- a/servo/components/style_derive/Cargo.toml
+++ b/servo/components/style_derive/Cargo.toml
@ -0,0 +1,15 @@
 [package]
 name = "style_derive"
 version = "0.0.1"
 authors = ["The Servo Project Developers"]
 license = "MPL-2.0"
 publish = false
 [lib]
 path = "lib.rs"
 proc-macro = true
 [dependencies]
 quote = "0.3"
 syn = "0.11"
 synstructure = "0.5.2"
--- a/servo/components/style_derive/has_viewport_percentage.rs
+++ b/servo/components/style_derive/has_viewport_percentage.rs
@ -0,0 +1,56 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 use quote;
 use syn;
 use synstructure;
 pub fn derive(input: syn::DeriveInput) -> quote::Tokens {
    let name = &input.ident;
    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
    let mut where_clause = where_clause.clone();
    for param in &input.generics.ty_params {
        where_clause.predicates.push(where_predicate(syn::Ty::Path(None, param.ident.clone().into())))
    }
    let style = synstructure::BindStyle::Ref.into();
    let match_body = synstructure::each_variant(&input, &style, |bindings, _| {
        let (first, rest) = match bindings.split_first() {
            None => return Some(quote!(false)),
            Some(pair) => pair,
        };
        let mut expr = quote!(::style_traits::HasViewportPercentage::has_viewport_percentage(#first));
        for binding in rest {
            where_clause.predicates.push(where_predicate(binding.field.ty.clone()));
            expr = quote!(#expr || ::style_traits::HasViewportPercentage::has_viewport_percentage(#binding));
        }
        Some(expr)
    });
    quote! {
        impl #impl_generics ::style_traits::HasViewportPercentage for #name #ty_generics #where_clause {
            #[allow(unused_variables, unused_imports)]
            #[inline]
            fn has_viewport_percentage(&self) -> bool {
                match *self {
                    #match_body
                }
            }
        }
    }
 }
 fn where_predicate(ty: syn::Ty) -> syn::WherePredicate {
    syn::WherePredicate::BoundPredicate(syn::WhereBoundPredicate {
        bound_lifetimes: vec![],
        bounded_ty: ty,
        bounds: vec![syn::TyParamBound::Trait(
            syn::PolyTraitRef {
                bound_lifetimes: vec![],
                trait_ref: syn::parse_path("::style_traits::HasViewportPercentage").unwrap(),
            },
            syn::TraitBoundModifier::None
        )],
    })
 }
--- a/servo/components/style_derive/lib.rs
+++ b/servo/components/style_derive/lib.rs
@ -0,0 +1,18 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 extern crate proc_macro;
 #[macro_use] extern crate quote;
 extern crate syn;
 extern crate synstructure;
 use proc_macro::TokenStream;
 mod has_viewport_percentage;
 #[proc_macro_derive(HasViewportPercentage)]
 pub fn derive_has_viewport_percentage(stream: TokenStream) -> TokenStream {
    let input = syn::parse_derive_input(&stream.to_string()).unwrap();
    has_viewport_percentage::derive(input).to_string().parse().unwrap()
 }
--- a/servo/components/style_traits/lib.rs
+++ b/servo/components/style_traits/lib.rs
@ -63,6 +63,8 @@ pub enum CSSPixel {}
 pub mod cursor;
 #[macro_use]
 pub mod values;
 #[macro_use]
 pub mod viewport;
 pub use values::{ToCss, OneOrMoreCommaSeparated};
 pub use viewport::HasViewportPercentage;
--- a/servo/components/style_traits/viewport.rs
+++ b/servo/components/style_traits/viewport.rs
@ -20,6 +20,48 @@ define_css_keyword_enum!(Orientation:
                         "portrait" => Portrait,
                         "landscape" => Landscape);
 /// A trait used to query whether this value has viewport units.
 pub trait HasViewportPercentage {
    /// Returns true if this value has viewport units.
    fn has_viewport_percentage(&self) -> bool;
 }
 /// A macro used to implement HasViewportPercentage trait
 /// for a given type that may never contain viewport units.
 #[macro_export]
 macro_rules! no_viewport_percentage {
    ($($name: ident),+) => {
        $(impl $crate::HasViewportPercentage for $name {
            #[inline]
            fn has_viewport_percentage(&self) -> bool {
                false
            }
        })+
    };
 }
 no_viewport_percentage!(bool, f32);
 impl<T: HasViewportPercentage> HasViewportPercentage for Box<T> {
    #[inline]
    fn has_viewport_percentage(&self) -> bool {
        (**self).has_viewport_percentage()
    }
 }
 impl<T: HasViewportPercentage> HasViewportPercentage for Option<T> {
    #[inline]
    fn has_viewport_percentage(&self) -> bool {
        self.as_ref().map_or(false, T::has_viewport_percentage)
    }
 }
 impl<T: HasViewportPercentage> HasViewportPercentage for Vec<T> {
    #[inline]
    fn has_viewport_percentage(&self) -> bool {
        self.iter().any(T::has_viewport_percentage)
    }
 }
 /// A set of viewport descriptors:
 ///
--- a/servo/tests/unit/style/attr.rs
+++ b/servo/tests/unit/style/attr.rs
@ -5,7 +5,6 @@
 use app_units::Au;
 use style::attr::{AttrValue, LengthOrPercentageOrAuto, parse_length};
 use style::values::computed::CalcLengthOrPercentage;
 use style_traits::values::specified::AllowedLengthType;
 #[test]
 fn test_length_calc() {
--- a/servo/tests/unit/style/restyle_hints.rs
+++ b/servo/tests/unit/style/restyle_hints.rs
@ -6,7 +6,7 @@
 fn smoke_restyle_hints() {
    use cssparser::Parser;
    use selectors::parser::SelectorList;
-    use style::restyle_hints::{DependencySet, RESTYLE_LATER_SIBLINGS};
+    use style::restyle_hints::DependencySet;
    use style::selector_parser::SelectorParser;
    use style::stylesheets::{Origin, Namespaces};
    let namespaces = Namespaces::default();
--- a/servo/tests/unit/style/stylist.rs
+++ b/servo/tests/unit/style/stylist.rs
@ -212,7 +212,7 @@ fn test_insert() {
 #[test]
 fn test_get_universal_rules() {
    thread_state::initialize(thread_state::LAYOUT);
-    let (map, shared_lock) = get_mock_map(&["*|*", "#foo > *|*", "*|* > *|*", ".klass", "#id"]);
+    let (map, _shared_lock) = get_mock_map(&["*|*", "#foo > *|*", "*|* > *|*", ".klass", "#id"]);
    let decls = map.get_universal_rules(CascadeLevel::UserNormal);