Auto merge of #14089 - Wafflespeanut:tocss, r=SimonSapin

Make use of Servo-specific ToCss everywhere!

<!-- Please describe your changes on the following line: -->

This will allow types to be generic over our local `ToCss`

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [ ] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors

<!-- Either: -->
- [x] These changes do not require tests because it's a refactor

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

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This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/14089)
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components/layout/query.rs

@@ -34,7 +34,7 @@ use style::properties::longhands::{display, position};
 use style::properties::style_structs;
 use style::selector_impl::PseudoElement;
 use style::selector_matching::Stylist;
-use style::values::LocalToCss;
+use style_traits::ToCss;
 use style_traits::cursor::Cursor;
 use wrapper::{LayoutNodeHelpers, LayoutNodeLayoutData};
 

components/script/dom/cssstyledeclaration.rs

@@ -2,7 +2,6 @@
  * 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 cssparser::ToCss;
 use dom::bindings::codegen::Bindings::CSSStyleDeclarationBinding::{self, CSSStyleDeclarationMethods};
 use dom::bindings::error::{Error, ErrorResult, Fallible};
 use dom::bindings::inheritance::Castable;
@@ -20,6 +19,7 @@ use style::parser::ParserContextExtraData;
 use style::properties::{Shorthand, Importance, PropertyDeclarationBlock};
 use style::properties::{is_supported_property, parse_one_declaration, parse_style_attribute};
 use style::selector_impl::PseudoElement;
+use style_traits::ToCss;
 
 // http://dev.w3.org/csswg/cssom/#the-cssstyledeclaration-interface
 #[dom_struct]

components/script/dom/mediaquerylist.rs

@@ -2,7 +2,6 @@
  * 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 cssparser::ToCss;
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
 use dom::bindings::codegen::Bindings::EventListenerBinding::EventListener;
@@ -22,7 +21,7 @@ use std::cell::Cell;
 use std::rc::Rc;
 use style;
 use style::media_queries::{Device, MediaType};
-use style_traits::{PagePx, ViewportPx};
+use style_traits::{PagePx, ToCss, ViewportPx};
 
 pub enum MediaQueryListMatchState {
     Same(bool),

components/servo/Cargo.lock

@@ -2429,6 +2429,7 @@ dependencies = [
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.8.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 0.8.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

components/style/custom_properties.rs

@@ -7,13 +7,14 @@
 //! [custom]: https://drafts.csswg.org/css-variables/
 
 use Atom;
-use cssparser::{Delimiter, Parser, SourcePosition, ToCss, Token, TokenSerializationType};
+use cssparser::{Delimiter, Parser, SourcePosition, Token, TokenSerializationType};
 use properties::DeclaredValue;
 use std::ascii::AsciiExt;
 use std::borrow::Cow;
 use std::collections::{HashMap, HashSet};
 use std::fmt;
 use std::sync::Arc;
+use style_traits::ToCss;
 
 // Does not include the `--` prefix
 pub type Name = Atom;

components/style/lib.rs

@@ -132,9 +132,9 @@ pub mod values;
 pub mod viewport;
 pub mod workqueue;
 
-use cssparser::ToCss;
 use std::fmt;
 use std::sync::Arc;
+use style_traits::ToCss;
 
 #[cfg(feature = "gecko")] pub use gecko_string_cache as string_cache;
 #[cfg(feature = "gecko")] pub use gecko_string_cache::Atom;

components/style/media_queries.rs

@@ -8,12 +8,12 @@
 
 use Atom;
 use app_units::Au;
-use cssparser::{Delimiter, Parser, ToCss, Token};
+use cssparser::{Delimiter, Parser, Token};
 use euclid::size::{Size2D, TypedSize2D};
 use properties::longhands;
 use serialize_comma_separated_list;
 use std::fmt::{self, Write};
-use style_traits::ViewportPx;
+use style_traits::{ToCss, ViewportPx};
 use values::specified;
 
 

components/style/properties/declaration_block.rs

@@ -2,13 +2,14 @@
  * 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 cssparser::{DeclarationListParser, parse_important, ToCss};
+use cssparser::{DeclarationListParser, parse_important};
 use cssparser::{Parser, AtRuleParser, DeclarationParser, Delimiter};
 use error_reporting::ParseErrorReporter;
 use parser::{ParserContext, ParserContextExtraData, log_css_error};
 use std::ascii::AsciiExt;
 use std::boxed::Box as StdBox;
 use std::fmt;
+use style_traits::ToCss;
 use stylesheets::Origin;
 use super::*;
 use url::Url;

components/style/properties/helpers.mako.rs

@@ -54,9 +54,9 @@
 <%def name="vector_longhand(name, gecko_only=False, allow_empty=False, **kwargs)">
     <%call expr="longhand(name, **kwargs)">
         % if product == "gecko" or not gecko_only:
-            use cssparser::ToCss;
             use std::fmt;
             use values::HasViewportPercentage;
+            use style_traits::ToCss;
 
             impl HasViewportPercentage for SpecifiedValue {
                 fn has_viewport_percentage(&self) -> bool {
@@ -324,6 +324,7 @@
     <%def name="inner_body()">
         pub use self::computed_value::T as SpecifiedValue;
         pub mod computed_value {
+            use style_traits::ToCss;
             define_css_keyword_enum! { T:
                 % for value in data.longhands_by_name[name].keyword.values_for(product):
                     "${value}" => ${to_rust_ident(value)},
@@ -370,8 +371,8 @@
         use values::NoViewportPercentage;
         impl NoViewportPercentage for SpecifiedValue {}
         pub mod computed_value {
-            use cssparser::ToCss;
             use std::fmt;
+            use style_traits::ToCss;
 
             #[derive(Debug, Clone, PartialEq)]
             #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
@@ -438,10 +439,11 @@
     % if shorthand:
     pub mod ${shorthand.ident} {
         #[allow(unused_imports)]
-        use cssparser::{Parser, ToCss};
+        use cssparser::Parser;
         use parser::ParserContext;
         use properties::{longhands, PropertyDeclaration, DeclaredValue, Shorthand};
         use std::fmt;
+        use style_traits::ToCss;
 
         pub struct Longhands {
             % for sub_property in shorthand.sub_properties:

components/style/properties/helpers/animated_properties.mako.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
-use cssparser::{Color as CSSParserColor, Parser, RGBA, ToCss};
+use cssparser::{Color as CSSParserColor, Parser, RGBA};
 use euclid::{Point2D, Size2D};
 use properties::PropertyDeclaration;
 use properties::longhands;
@@ -20,6 +20,7 @@ use properties::longhands::visibility::computed_value::T as Visibility;
 use properties::longhands::z_index::computed_value::T as ZIndex;
 use std::cmp;
 use std::fmt;
+use style_traits::ToCss;
 use super::ComputedValues;
 use values::computed::{Angle, LengthOrPercentageOrAuto, LengthOrPercentageOrNone};
 use values::computed::{BorderRadiusSize, LengthOrNone};

components/style/properties/longhand/background.mako.rs

@@ -12,10 +12,9 @@ ${helpers.predefined_type("background-color", "CSSColor",
 
 <%helpers:vector_longhand name="background-image" animatable="False"
                           has_uncacheable_values="${product == 'gecko'}">
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
     use values::specified::Image;
-    use values::LocalToCss;
     use values::NoViewportPercentage;
 
     pub mod computed_value {
@@ -88,9 +87,8 @@ ${helpers.predefined_type("background-color", "CSSColor",
 </%helpers:vector_longhand>
 
 <%helpers:vector_longhand name="background-position" animatable="True">
-        use cssparser::ToCss;
         use std::fmt;
-        use values::LocalToCss;
+        use style_traits::ToCss;
         use values::HasViewportPercentage;
         use values::specified::position::Position;
 
@@ -149,9 +147,10 @@ ${helpers.single_keyword("background-origin",
                          animatable=False)}
 
 <%helpers:vector_longhand name="background-size" animatable="True">
-    use cssparser::{ToCss, Token};
+    use cssparser::Token;
     use std::ascii::AsciiExt;
     use std::fmt;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
 
     pub mod computed_value {

components/style/properties/longhand/border.mako.rs

@@ -24,8 +24,8 @@
 % for side in ["top", "right", "bottom", "left"]:
     <%helpers:longhand name="border-${side}-width" animatable="True">
         use app_units::Au;
-        use cssparser::ToCss;
         use std::fmt;
+        use style_traits::ToCss;
         use values::HasViewportPercentage;
         use values::specified::BorderWidth;
 
@@ -67,9 +67,8 @@ ${helpers.single_keyword("-moz-float-edge", "content-box margin-box",
 
 // https://drafts.csswg.org/css-backgrounds-3/#border-image-source
 <%helpers:longhand name="border-image-source" products="gecko" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
     use values::specified::Image;
 
@@ -139,10 +138,9 @@ ${helpers.single_keyword("-moz-float-edge", "content-box margin-box",
 
 // https://drafts.csswg.org/css-backgrounds-3/#border-image-outset
 <%helpers:longhand name="border-image-outset" products="gecko" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
-    use values::LocalToCss;
     use values::specified::LengthOrNumber;
 
     impl HasViewportPercentage for SpecifiedValue {
@@ -253,9 +251,8 @@ ${helpers.single_keyword("-moz-float-edge", "content-box margin-box",
 
 // https://drafts.csswg.org/css-backgrounds-3/#border-image-repeat
 <%helpers:longhand name="border-image-repeat" products="gecko" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
 
     impl NoViewportPercentage for SpecifiedValue {}
@@ -327,9 +324,8 @@ ${helpers.single_keyword("-moz-float-edge", "content-box margin-box",
 
 // https://drafts.csswg.org/css-backgrounds-3/#border-image-width
 <%helpers:longhand name="border-image-width" products="gecko" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
     use values::specified::{LengthOrPercentage, Number};
 
@@ -523,9 +519,8 @@ ${helpers.single_keyword("-moz-float-edge", "content-box margin-box",
 
 // https://drafts.csswg.org/css-backgrounds-3/#border-image-slice
 <%helpers:longhand name="border-image-slice" products="gecko" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
     use values::specified::{Number, Percentage};
 

components/style/properties/longhand/box.mako.rs

@@ -27,11 +27,12 @@
     %>
     pub use self::computed_value::T as SpecifiedValue;
     use values::computed::ComputedValueAsSpecified;
-
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
     impl NoViewportPercentage for SpecifiedValue {}
 
     pub mod computed_value {
+        use style_traits::ToCss;
         #[allow(non_camel_case_types)]
         #[derive(Clone, Eq, PartialEq, Copy, Hash, RustcEncodable, Debug)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
@@ -41,7 +42,7 @@
             % endfor
         }
 
-        impl ::cssparser::ToCss for T {
+        impl ToCss for T {
             fn to_css<W>(&self, dest: &mut W) -> ::std::fmt::Result
             where W: ::std::fmt::Write {
                 match *self {
@@ -148,8 +149,9 @@ ${helpers.single_keyword("clear", "none left right both",
 
 <%helpers:longhand name="vertical-align"
                    animatable="True">
-  use cssparser::ToCss;
   use std::fmt;
+  use style_traits::ToCss;
+  use values::HasViewportPercentage;
 
   <% vertical_align = data.longhands_by_name["vertical-align"] %>
   <% vertical_align.keyword = Keyword("vertical-align",
@@ -157,7 +159,6 @@ ${helpers.single_keyword("clear", "none left right both",
                                       extra_gecko_values="middle-with-baseline") %>
   <% vertical_align_keywords = vertical_align.keyword.values_for(product) %>
 
-  use values::HasViewportPercentage;
   impl HasViewportPercentage for SpecifiedValue {
       fn has_viewport_percentage(&self) -> bool {
           match *self {
@@ -204,7 +205,7 @@ ${helpers.single_keyword("clear", "none left right both",
   pub mod computed_value {
       use app_units::Au;
       use std::fmt;
-      use values::LocalToCss;
+      use style_traits::ToCss;
       use values::{CSSFloat, computed};
       #[allow(non_camel_case_types)]
       #[derive(PartialEq, Copy, Clone, Debug)]
@@ -215,7 +216,7 @@ ${helpers.single_keyword("clear", "none left right both",
           % endfor
           LengthOrPercentage(computed::LengthOrPercentage),
       }
-      impl ::cssparser::ToCss for T {
+      impl ToCss for T {
           fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
               match *self {
                   % for keyword in vertical_align_keywords:
@@ -282,13 +283,13 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
                    animatable="False">
   use super::overflow_x;
 
-  use cssparser::ToCss;
   use std::fmt;
+  use style_traits::ToCss;
   use values::computed::ComputedValueAsSpecified;
+  use values::NoViewportPercentage;
 
   pub use self::computed_value::T as SpecifiedValue;
 
-  use values::NoViewportPercentage;
   impl NoViewportPercentage for SpecifiedValue {}
 
   impl ToCss for SpecifiedValue {
@@ -327,8 +328,8 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
     impl NoViewportPercentage for SpecifiedValue {}
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use std::fmt;
+        use style_traits::ToCss;
         use values::computed::{Context, ToComputedValue};
 
         pub use values::computed::Time as SingleComputedValue;
@@ -426,9 +427,9 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
         TransitionTimingFunction::Steps(1, StartEnd::End);
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use euclid::point::Point2D;
         use std::fmt;
+        use style_traits::ToCss;
         use values::computed::ComputedValueAsSpecified;
 
         pub use self::TransitionTimingFunction as SingleComputedValue;
@@ -581,8 +582,8 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
     pub use self::computed_value::T as SpecifiedValue;
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use std::fmt;
+        use style_traits::ToCss;
         // NB: Can't generate the type here because it needs all the longhands
         // generated beforehand.
         pub use properties::animated_properties::TransitionProperty;
@@ -646,9 +647,9 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
     use values::NoViewportPercentage;
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use std::fmt;
         use Atom;
+        use style_traits::ToCss;
 
         pub use Atom as SingleComputedValue;
 
@@ -732,8 +733,8 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto",
     use values::NoViewportPercentage;
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use std::fmt;
+        use style_traits::ToCss;
 
         pub use self::AnimationIterationCount as SingleComputedValue;
 
@@ -842,9 +843,8 @@ ${helpers.keyword_list("animation-fill-mode",
 </%helpers:longhand>
 
 <%helpers:longhand products="gecko" name="scroll-snap-points-y" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
     use values::specified::LengthOrPercentage;
 

components/style/properties/longhand/column.mako.rs

@@ -8,9 +8,8 @@
 
 // FIXME: This prop should be animatable.
 <%helpers:longhand name="column-width" experimental="True" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
 
     impl HasViewportPercentage for SpecifiedValue {
@@ -91,8 +90,8 @@
 
 // FIXME: This prop should be animatable.
 <%helpers:longhand name="column-count" experimental="True" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
 
     impl NoViewportPercentage for SpecifiedValue {}
@@ -171,9 +170,8 @@
 
 // FIXME: This prop should be animatable.
 <%helpers:longhand name="column-gap" experimental="True" products="servo" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
 
     impl HasViewportPercentage for SpecifiedValue {

components/style/properties/longhand/counters.mako.rs

@@ -23,8 +23,9 @@
     pub mod computed_value {
         use super::super::list_style_type;
 
-        use cssparser::{self, ToCss};
+        use cssparser;
         use std::fmt;
+        use style_traits::ToCss;
 
         #[derive(Debug, PartialEq, Eq, Clone)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
@@ -175,11 +176,12 @@
 
 <%helpers:longhand name="counter-increment" products="servo" animatable="False">
     use std::fmt;
+    use style_traits::ToCss;
     use super::content;
     use values::NoViewportPercentage;
     use values::computed::ComputedValueAsSpecified;
 
-    use cssparser::{ToCss, Token, serialize_identifier};
+    use cssparser::{Token, serialize_identifier};
     use std::borrow::{Cow, ToOwned};
 
     pub use self::computed_value::T as SpecifiedValue;

components/style/properties/longhand/effects.mako.rs

@@ -13,10 +13,10 @@ ${helpers.predefined_type("opacity",
                           animatable=True)}
 
 <%helpers:vector_longhand name="box-shadow" allow_empty="True" animatable="True">
-    use cssparser::{self, ToCss};
+    use cssparser;
     use std::fmt;
     use parser::Parse;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
 
     #[derive(Debug, Clone, PartialEq)]
@@ -189,9 +189,8 @@ ${helpers.predefined_type("opacity",
 
 // FIXME: This prop should be animatable
 <%helpers:longhand name="clip" products="servo" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
 
     // NB: `top` and `left` are 0 if `auto` per CSS 2.1 11.1.2.
@@ -405,11 +404,9 @@ ${helpers.predefined_type("opacity",
 // FIXME: This prop should be animatable
 <%helpers:longhand name="filter" animatable="False">
     //pub use self::computed_value::T as SpecifiedValue;
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
-    use values::CSSFloat;
+    use values::{CSSFloat, HasViewportPercentage};
-    use values::HasViewportPercentage;
     use values::specified::{Angle, Length};
 
     impl HasViewportPercentage for SpecifiedValue {
@@ -675,11 +672,9 @@ ${helpers.predefined_type("opacity",
 
 <%helpers:longhand name="transform" products="servo" animatable="True">
     use app_units::Au;
-    use values::CSSFloat;
-    use values::HasViewportPercentage;
-
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
+    use values::{CSSFloat, HasViewportPercentage};
 
     pub mod computed_value {
         use values::CSSFloat;
@@ -1293,13 +1288,11 @@ ${helpers.single_keyword("transform-style",
 
 <%helpers:longhand name="transform-origin" products="servo" animatable="True">
     use app_units::Au;
-    use values::LocalToCss;
+    use std::fmt;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
     use values::specified::{Length, LengthOrPercentage, Percentage};
 
-    use cssparser::ToCss;
-    use std::fmt;
-
     pub mod computed_value {
         use properties::animated_properties::Interpolate;
         use values::computed::{Length, LengthOrPercentage};
@@ -1408,12 +1401,11 @@ ${helpers.predefined_type("perspective",
 
 // FIXME: This prop should be animatable
 <%helpers:longhand name="perspective-origin" products="servo" animatable="False">
+    use std::fmt;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
     use values::specified::{LengthOrPercentage, Percentage};
 
-    use cssparser::ToCss;
-    use std::fmt;
-
     pub mod computed_value {
         use values::computed::LengthOrPercentage;
 

components/style/properties/longhand/font.mako.rs

@@ -18,9 +18,9 @@
     impl NoViewportPercentage for SpecifiedValue {}
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use std::fmt;
         use Atom;
+        use style_traits::ToCss;
 
         #[derive(Debug, PartialEq, Eq, Clone, Hash)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
@@ -137,8 +137,8 @@ ${helpers.single_keyword("font-variant",
                          animatable=False)}
 
 <%helpers:longhand name="font-weight" need_clone="True" animatable="True">
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
 
     impl NoViewportPercentage for SpecifiedValue {}
@@ -271,10 +271,9 @@ ${helpers.single_keyword("font-variant",
 
 <%helpers:longhand name="font-size" need_clone="True" animatable="True">
     use app_units::Au;
-    use cssparser::ToCss;
     use std::fmt;
-    use values::FONT_MEDIUM_PX;
+    use style_traits::ToCss;
-    use values::HasViewportPercentage;
+    use values::{FONT_MEDIUM_PX, HasViewportPercentage};
     use values::specified::{LengthOrPercentage, Length, Percentage};
 
     impl ToCss for SpecifiedValue {
@@ -351,11 +350,10 @@ ${helpers.single_keyword("font-variant",
 </%helpers:longhand>
 
 <%helpers:longhand products="gecko" name="font-synthesis" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
-    use values::computed::ComputedValueAsSpecified;
     use values::NoViewportPercentage;
+    use values::computed::ComputedValueAsSpecified;
 
     impl ComputedValueAsSpecified for SpecifiedValue {}
     impl NoViewportPercentage for SpecifiedValue {}
@@ -438,8 +436,8 @@ ${helpers.single_keyword("font-variant-position",
                          animatable=False)}
 
 <%helpers:longhand name="font-feature-settings" products="none" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
     use values::computed::ComputedValueAsSpecified;
     pub use self::computed_value::T as SpecifiedValue;
@@ -448,9 +446,9 @@ ${helpers.single_keyword("font-variant-position",
     impl NoViewportPercentage for SpecifiedValue {}
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use cssparser::Parser;
         use std::fmt;
+        use style_traits::ToCss;
 
         #[derive(Debug, Clone, PartialEq)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
@@ -555,8 +553,8 @@ ${helpers.single_keyword("font-variant-position",
     impl NoViewportPercentage for SpecifiedValue {}
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use std::fmt;
+        use style_traits::ToCss;
 
         impl ToCss for T {
             fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {

components/style/properties/longhand/inherited_box.mako.rs

@@ -56,8 +56,8 @@ ${helpers.single_keyword("image-rendering",
                    derived_from="display"
                    products="servo"
                    animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
     use values::computed::ComputedValueAsSpecified;
     use values::NoViewportPercentage;
 

components/style/properties/longhand/inherited_table.mako.rs

@@ -18,11 +18,9 @@ ${helpers.single_keyword("caption-side", "top bottom",
 
 <%helpers:longhand name="border-spacing" animatable="False">
     use app_units::Au;
-    use values::LocalToCss;
-    use values::HasViewportPercentage;
-
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
+    use values::HasViewportPercentage;
 
     pub mod computed_value {
         use app_units::Au;

components/style/properties/longhand/inherited_text.mako.rs

@@ -7,11 +7,9 @@
 <% data.new_style_struct("InheritedText", inherited=True, gecko_name="Text") %>
 
 <%helpers:longhand name="line-height" animatable="True">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
-    use values::CSSFloat;
+    use values::{CSSFloat, HasViewportPercentage};
-    use values::HasViewportPercentage;
 
     impl HasViewportPercentage for SpecifiedValue {
         fn has_viewport_percentage(&self) -> bool {
@@ -153,6 +151,7 @@
     impl ComputedValueAsSpecified for SpecifiedValue {}
     impl NoViewportPercentage for SpecifiedValue {}
     pub mod computed_value {
+        use style_traits::ToCss;
         macro_rules! define_text_align {
             ( $( $name: ident ( $string: expr ) => $discriminant: expr, )+ ) => {
                 define_css_keyword_enum! { T:
@@ -209,9 +208,8 @@
 
 // FIXME: This prop should be animatable.
 <%helpers:longhand name="letter-spacing" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
 
     impl HasViewportPercentage for SpecifiedValue {
@@ -290,9 +288,8 @@
 </%helpers:longhand>
 
 <%helpers:longhand name="word-spacing" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
 
     impl HasViewportPercentage for SpecifiedValue {
@@ -405,10 +402,10 @@ ${helpers.single_keyword("text-align-last",
                    derived_from="display text-decoration"
                    need_clone="True" products="servo"
                    animatable="False">
-    use cssparser::{RGBA, ToCss};
+    use cssparser::RGBA;
     use std::fmt;
-
+    use style_traits::ToCss;
-    use values:: NoViewportPercentage;
+    use values::NoViewportPercentage;
     use values::computed::ComputedValueAsSpecified;
 
     impl ComputedValueAsSpecified for SpecifiedValue {}
@@ -529,9 +526,9 @@ ${helpers.single_keyword("text-align-last",
 </%helpers:single_keyword_computed>
 
 <%helpers:longhand name="text-shadow" animatable="True">
-    use cssparser::{self, ToCss};
+    use cssparser;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
 
     impl HasViewportPercentage for SpecifiedValue {
@@ -739,10 +736,9 @@ ${helpers.single_keyword("text-align-last",
 
 <%helpers:longhand name="text-emphasis-style" products="gecko" need_clone="True" animatable="False">
     use computed_values::writing_mode::T as writing_mode;
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
     use unicode_segmentation::UnicodeSegmentation;
-    use values::LocalToCss;
     use values::NoViewportPercentage;
 
     impl NoViewportPercentage for SpecifiedValue {}

components/style/properties/longhand/list.mako.rs

@@ -31,12 +31,12 @@ ${helpers.predefined_type("list-style-image", "UrlOrNone", "computed_value::T::N
                           animatable="False")}
 
 <%helpers:longhand name="quotes" animatable="False">
+    use cssparser::Token;
     use std::borrow::Cow;
     use std::fmt;
-    use values::NoViewportPercentage;
+    use style_traits::ToCss;
     use values::computed::ComputedValueAsSpecified;
-
+    use values::NoViewportPercentage;
-    use cssparser::{ToCss, Token};
 
     pub use self::computed_value::T as SpecifiedValue;
 

components/style/properties/longhand/outline.mako.rs

@@ -29,9 +29,8 @@ ${helpers.predefined_type("outline-color", "CSSColor", "::cssparser::Color::Curr
 
 <%helpers:longhand name="outline-width" animatable="True">
     use app_units::Au;
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::HasViewportPercentage;
 
     impl ToCss for SpecifiedValue {

components/style/properties/longhand/pointing.mako.rs

@@ -15,9 +15,9 @@
     impl NoViewportPercentage for SpecifiedValue {}
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use std::fmt;
         use style_traits::cursor::Cursor;
+        use style_traits::ToCss;
 
         #[derive(Clone, PartialEq, Eq, Copy, Debug)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf))]

components/style/properties/longhand/position.mako.rs

@@ -20,8 +20,8 @@
     impl NoViewportPercentage for SpecifiedValue {}
     pub type SpecifiedValue = computed_value::T;
     pub mod computed_value {
-        use cssparser::ToCss;
         use std::fmt;
+        use style_traits::ToCss;
 
         #[derive(PartialEq, Clone, Eq, Copy, Debug)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf))]

components/style/properties/longhand/svg.mako.rs

@@ -51,9 +51,8 @@ ${helpers.single_keyword("mask-type", "luminance alpha",
                          products="gecko", animatable=False)}
 
 <%helpers:longhand name="clip-path" animatable="False" products="gecko">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::LocalToCss;
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
     use values::specified::basic_shape::{ShapeSource, GeometryBox};
 
@@ -148,18 +147,17 @@ ${helpers.single_keyword("mask-composite",
 
 <%helpers:vector_longhand name="mask-image" products="gecko" animatable="False"
                           has_uncacheable_values="${product == 'gecko'}">
-    use cssparser::ToCss;
     use std::fmt;
+    use style_traits::ToCss;
     use url::Url;
     use values::specified::{Image, UrlExtraData};
-    use values::LocalToCss;
     use values::NoViewportPercentage;
 
     pub mod computed_value {
-        use cssparser::ToCss;
         use std::fmt;
+        use style_traits::ToCss;
         use url::Url;
-        use values::{computed, LocalToCss};
+        use values::computed;
         #[derive(Debug, Clone, PartialEq)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
         pub enum T {

components/style/properties/longhand/text.mako.rs

@@ -16,10 +16,10 @@
     ${helpers.single_keyword("text-overflow", "clip ellipsis", animatable=False)}
 % else:
 <%helpers:longhand name="text-overflow" animatable="False">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::computed::ComputedValueAsSpecified;
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
+    use values::computed::ComputedValueAsSpecified;
 
     impl ComputedValueAsSpecified for SpecifiedValue {}
     impl NoViewportPercentage for SpecifiedValue {}
@@ -104,10 +104,10 @@ ${helpers.single_keyword("unicode-bidi",
                    custom_cascade="${product == 'servo'}"
                    animatable="False"
                    disable_when_testing="True">
-    use cssparser::ToCss;
     use std::fmt;
-    use values::computed::ComputedValueAsSpecified;
+    use style_traits::ToCss;
     use values::NoViewportPercentage;
+    use values::computed::ComputedValueAsSpecified;
 
     impl ComputedValueAsSpecified for SpecifiedValue {}
     impl NoViewportPercentage for SpecifiedValue {}

components/style/properties/properties.mako.rs

@@ -19,7 +19,7 @@ use std::sync::Arc;
 use Atom;
 use app_units::Au;
 #[cfg(feature = "servo")] use cssparser::{Color as CSSParserColor, RGBA};
-use cssparser::{Parser, ToCss, TokenSerializationType};
+use cssparser::{Parser, TokenSerializationType};
 use error_reporting::ParseErrorReporter;
 use url::Url;
 #[cfg(feature = "servo")] use euclid::side_offsets::SideOffsets2D;
@@ -28,10 +28,9 @@ use computed_values;
 #[cfg(feature = "servo")] use logical_geometry::{LogicalMargin, PhysicalSide};
 use logical_geometry::WritingMode;
 use parser::{ParserContext, ParserContextExtraData};
+use style_traits::ToCss;
 use stylesheets::Origin;
-#[cfg(feature = "servo")] use values::LocalToCss;
+use values::{HasViewportPercentage, computed};
-use values::HasViewportPercentage;
-use values::computed;
 use cascade_info::CascadeInfo;
 use rule_tree::StrongRuleNode;
 #[cfg(feature = "servo")] use values::specified::BorderStyle;

components/style/properties/shorthand/serialize.mako.rs

@@ -2,8 +2,8 @@
  * 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 cssparser::ToCss;
 use properties::{AppendableValue, DeclaredValue, PropertyDeclaration, Shorthand};
+use style_traits::ToCss;
 use values::specified::{BorderStyle, CSSColor};
 use std::fmt;
 

components/style/values/computed/basic_shape.rs

@@ -7,9 +7,9 @@
 //!
 //! [basic-shape]: https://drafts.csswg.org/css-shapes/#typedef-basic-shape
 
-use cssparser::ToCss;
 use properties::shorthands::serialize_four_sides;
 use std::fmt;
+use style_traits::ToCss;
 use url::Url;
 use values::computed::{BorderRadiusSize, LengthOrPercentage};
 use values::computed::UrlExtraData;
@@ -34,7 +34,6 @@ impl<T> Default for ShapeSource<T> {
 
 impl<T: ToCss> ToCss for ShapeSource<T> {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        use values::LocalToCss;
         match *self {
             ShapeSource::Url(ref url, _) => url.to_css(dest),
             ShapeSource::Shape(ref shape, Some(ref reference)) => {

components/style/values/computed/image.rs

@@ -9,12 +9,11 @@
 
 use cssparser::Color as CSSColor;
 use std::fmt;
+use style_traits::ToCss;
 use url::Url;
-use values::LocalToCss;
 use values::computed::{Context, Length, LengthOrPercentage, ToComputedValue};
 use values::computed::position::Position;
-use values::specified;
+use values::specified::{self, AngleOrCorner, SizeKeyword, UrlExtraData};
-use values::specified::{AngleOrCorner, SizeKeyword, UrlExtraData};
 
 
 impl ToComputedValue for specified::Image {
@@ -73,9 +72,8 @@ impl fmt::Debug for Image {
     }
 }
 
-impl ::cssparser::ToCss for Image {
+impl ToCss for Image {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        use values::LocalToCss;
         match *self {
             Image::Url(ref url, _) => {
                 url.to_css(dest)
@@ -98,7 +96,7 @@ pub struct Gradient {
     pub gradient_kind: GradientKind,
 }
 
-impl ::cssparser::ToCss for Gradient {
+impl ToCss for Gradient {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         if self.repeating {
             try!(dest.write_str("repeating-"));
@@ -224,7 +222,7 @@ pub struct ColorStop {
     pub position: Option<LengthOrPercentage>,
 }
 
-impl ::cssparser::ToCss for ColorStop {
+impl ToCss for ColorStop {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         try!(self.color.to_css(dest));
         if let Some(position) = self.position {
@@ -279,7 +277,7 @@ pub enum EndingShape {
     Ellipse(LengthOrPercentageOrKeyword),
 }
 
-impl ::cssparser::ToCss for EndingShape {
+impl ToCss for EndingShape {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
             EndingShape::Circle(ref length) => {
@@ -344,7 +342,7 @@ pub enum LengthOrKeyword {
     Keyword(SizeKeyword),
 }
 
-impl ::cssparser::ToCss for LengthOrKeyword {
+impl ToCss for LengthOrKeyword {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
             LengthOrKeyword::Length(ref length) => length.to_css(dest),
@@ -402,7 +400,7 @@ pub enum LengthOrPercentageOrKeyword {
     Keyword(SizeKeyword),
 }
 
-impl ::cssparser::ToCss for LengthOrPercentageOrKeyword {
+impl ToCss for LengthOrPercentageOrKeyword {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
             LengthOrPercentageOrKeyword::LengthOrPercentage(ref first_len, second_len) => {

components/style/values/computed/length.rs

@@ -5,8 +5,9 @@
 use app_units::Au;
 use ordered_float::NotNaN;
 use std::fmt;
+use style_traits::ToCss;
 use super::{Number, ToComputedValue, Context};
-use values::{CSSFloat, LocalToCss, specified};
+use values::{CSSFloat, specified};
 
 pub use cssparser::Color as CSSColor;
 pub use super::image::{EndingShape as GradientShape, Gradient, GradientKind, Image};
@@ -79,7 +80,7 @@ impl From<LengthOrPercentageOrAuto> for Option<CalcLengthOrPercentage> {
     }
 }
 
-impl ::cssparser::ToCss for CalcLengthOrPercentage {
+impl ToCss for CalcLengthOrPercentage {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match (self.length, self.percentage) {
             (None, Some(p)) => write!(dest, "{}%", p * 100.),
@@ -192,7 +193,7 @@ impl ToComputedValue for specified::LengthOrPercentage {
     }
 }
 
-impl ::cssparser::ToCss for LengthOrPercentage {
+impl ToCss for LengthOrPercentage {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
             LengthOrPercentage::Length(length) => length.to_css(dest),
@@ -279,7 +280,7 @@ impl ToComputedValue for specified::LengthOrPercentageOrAuto {
     }
 }
 
-impl ::cssparser::ToCss for LengthOrPercentageOrAuto {
+impl ToCss for LengthOrPercentageOrAuto {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
             LengthOrPercentageOrAuto::Length(length) => length.to_css(dest),
@@ -364,7 +365,7 @@ impl ToComputedValue for specified::LengthOrPercentageOrAutoOrContent {
     }
 }
 
-impl ::cssparser::ToCss for LengthOrPercentageOrAutoOrContent {
+impl ToCss for LengthOrPercentageOrAutoOrContent {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
             LengthOrPercentageOrAutoOrContent::Length(length) => length.to_css(dest),
@@ -439,7 +440,7 @@ impl ToComputedValue for specified::LengthOrPercentageOrNone {
     }
 }
 
-impl ::cssparser::ToCss for LengthOrPercentageOrNone {
+impl ToCss for LengthOrPercentageOrNone {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
             LengthOrPercentageOrNone::Length(length) => length.to_css(dest),
@@ -498,7 +499,7 @@ impl ToComputedValue for specified::LengthOrNone {
     }
 }
 
-impl ::cssparser::ToCss for LengthOrNone {
+impl ToCss for LengthOrNone {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
             LengthOrNone::Length(length) => length.to_css(dest),
@@ -546,7 +547,7 @@ impl ToComputedValue for specified::LengthOrNumber {
     }
 }
 
-impl ::cssparser::ToCss for LengthOrNumber {
+impl ToCss for LengthOrNumber {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
             LengthOrNumber::Length(len) => len.to_css(dest),

components/style/values/computed/mod.rs

@@ -6,6 +6,7 @@ use app_units::Au;
 use euclid::size::Size2D;
 use properties::ComputedValues;
 use std::fmt;
+use style_traits::ToCss;
 use super::{CSSFloat, specified};
 
 pub use cssparser::Color as CSSColor;
@@ -111,6 +112,7 @@ impl ToComputedValue for specified::Length {
     }
 }
 
+
 #[derive(Debug, PartialEq, Clone, Copy)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct BorderRadiusSize(pub Size2D<LengthOrPercentage>);
@@ -139,7 +141,7 @@ impl ToComputedValue for specified::BorderRadiusSize {
     }
 }
 
-impl ::cssparser::ToCss for BorderRadiusSize {
+impl ToCss for BorderRadiusSize {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         try!(self.0.width.to_css(dest));
         try!(dest.write_str("/"));

components/style/values/computed/position.rs

@@ -7,8 +7,8 @@
 //!
 //! [position]: https://drafts.csswg.org/css-backgrounds-3/#position
 
-use cssparser::ToCss;
 use std::fmt;
+use style_traits::ToCss;
 use values::computed::LengthOrPercentage;
 
 #[derive(Debug, Clone, PartialEq, Copy)]

components/style/values/mod.rs

@@ -8,11 +8,6 @@
 
 pub use cssparser::RGBA;
 
-use app_units::Au;
-use cssparser::CssStringWriter;
-use std::fmt::{self, Write};
-use url::Url;
-
 macro_rules! define_numbered_css_keyword_enum {
     ($name: ident: $( $css: expr => $variant: ident = $value: expr ),+,) => {
         define_numbered_css_keyword_enum!($name: $( $css => $variant = $value ),+);
@@ -34,7 +29,7 @@ macro_rules! define_numbered_css_keyword_enum {
             }
         }
 
-        impl ::cssparser::ToCss for $name {
+        impl ToCss for $name {
             fn to_css<W>(&self, dest: &mut W) -> ::std::fmt::Result
             where W: ::std::fmt::Write {
                 match *self {
@@ -48,38 +43,6 @@ macro_rules! define_numbered_css_keyword_enum {
 pub mod computed;
 pub mod specified;
 
-/// The real ToCss trait can't be implemented for types in crates that don't
-/// depend on each other.
-pub trait LocalToCss {
-    /// Serialize `self` in CSS syntax, writing to `dest`.
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write;
-
-    /// Serialize `self` in CSS syntax and return a string.
-    ///
-    /// (This is a convenience wrapper for `to_css` and probably should not be overridden.)
-    #[inline]
-    fn to_css_string(&self) -> String {
-        let mut s = String::new();
-        self.to_css(&mut s).unwrap();
-        s
-    }
-}
-
-impl LocalToCss for Au {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        write!(dest, "{}px", self.to_f64_px())
-    }
-}
-
-impl LocalToCss for Url {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        try!(dest.write_str("url(\""));
-        try!(write!(CssStringWriter::new(dest), "{}", self));
-        try!(dest.write_str("\")"));
-        Ok(())
-    }
-}
-
 pub type CSSFloat = f32;
 
 pub const FONT_MEDIUM_PX: i32 = 16;

components/style/values/specified/basic_shape.rs

@@ -7,10 +7,11 @@
 //!
 //! [basic-shape]: https://drafts.csswg.org/css-shapes/#typedef-basic-shape
 
-use cssparser::{Parser, ToCss};
+use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use properties::shorthands::{parse_four_sides, serialize_four_sides};
 use std::fmt;
+use style_traits::ToCss;
 use url::Url;
 use values::computed::{ComputedValueAsSpecified, Context, ToComputedValue};
 use values::computed::basic_shape as computed_basic_shape;
@@ -39,7 +40,6 @@ impl<T> Default for ShapeSource<T> {
 
 impl<T: ToCss> ToCss for ShapeSource<T> {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        use values::LocalToCss;
         match *self {
             ShapeSource::Url(ref url, _) => url.to_css(dest),
             ShapeSource::Shape(ref shape, Some(ref reference)) => {

components/style/values/specified/image.rs

@@ -7,10 +7,11 @@
 //!
 //! [image]: https://drafts.csswg.org/css-images/#image-values
 
-use cssparser::{Parser, ToCss};
+use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use std::f32::consts::PI;
 use std::fmt;
+use style_traits::ToCss;
 use url::Url;
 use values::computed::ComputedValueAsSpecified;
 use values::specified::{Angle, CSSColor, Length, LengthOrPercentage, UrlExtraData};
@@ -27,7 +28,6 @@ pub enum Image {
 
 impl ToCss for Image {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        use values::LocalToCss;
         match *self {
             Image::Url(ref url, ref _extra_data) => {
                 url.to_css(dest)

components/style/values/specified/length.rs

@@ -3,16 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
-use cssparser::{Parser, ToCss, Token};
+use cssparser::{Parser, Token};
 use euclid::size::Size2D;
 use parser::Parse;
 use std::ascii::AsciiExt;
 use std::cmp;
 use std::fmt;
 use std::ops::Mul;
+use style_traits::ToCss;
 use style_traits::values::specified::AllowedNumericType;
 use super::{Angle, Number, SimplifiedValueNode, SimplifiedSumNode, Time};
-use values::{CSSFloat, FONT_MEDIUM_PX, HasViewportPercentage, LocalToCss, computed};
+use values::{CSSFloat, FONT_MEDIUM_PX, HasViewportPercentage, computed};
 
 pub use super::image::{AngleOrCorner, ColorStop, EndingShape as GradientEndingShape, Gradient};
 pub use super::image::{GradientKind, HorizontalDirection, Image, LengthOrKeyword, LengthOrPercentageOrKeyword};

components/style/values/specified/mod.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
-use cssparser::{self, Parser, ToCss, Token};
+use cssparser::{self, Parser, Token};
 use euclid::size::Size2D;
 #[cfg(feature = "gecko")]
 use gecko_bindings::sugar::refptr::{GeckoArcPrincipal, GeckoArcURI};
@@ -14,6 +14,7 @@ use std::ascii::AsciiExt;
 use std::f32::consts::PI;
 use std::fmt;
 use std::ops::Mul;
+use style_traits::ToCss;
 use super::{CSSFloat, HasViewportPercentage, NoViewportPercentage};
 use super::computed::{ComputedValueAsSpecified, Context, ToComputedValue};
 use url::Url;
@@ -555,7 +556,6 @@ impl NoViewportPercentage for UrlOrNone {}
 
 impl ToCss for UrlOrNone {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        use values::LocalToCss;
         match *self {
             UrlOrNone::Url(ref url, _) => {
                 url.to_css(dest)

components/style/values/specified/position.rs

@@ -7,9 +7,10 @@
 //!
 //! [position]: https://drafts.csswg.org/css-backgrounds-3/#position
 
-use cssparser::{Parser, ToCss, Token};
+use cssparser::{Parser, Token};
 use parser::Parse;
 use std::fmt;
+use style_traits::ToCss;
 use values::HasViewportPercentage;
 use values::computed::{CalcLengthOrPercentage, Context};
 use values::computed::{LengthOrPercentage as ComputedLengthOrPercentage, ToComputedValue};

components/style/viewport.rs

@@ -9,7 +9,6 @@
 
 use app_units::Au;
 use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser, Parser, parse_important};
-use cssparser::ToCss;
 use euclid::scale_factor::ScaleFactor;
 use euclid::size::{Size2D, TypedSize2D};
 use media_queries::Device;
@@ -20,7 +19,7 @@ use std::borrow::Cow;
 use std::fmt;
 use std::iter::Enumerate;
 use std::str::Chars;
-use style_traits::ViewportPx;
+use style_traits::{ToCss, ViewportPx};
 use style_traits::viewport::{Orientation, UserZoom, ViewportConstraints, Zoom};
 use stylesheets::{Stylesheet, Origin};
 use values::computed::{Context, ToComputedValue};

components/style_traits/Cargo.toml

@@ -22,3 +22,4 @@ heapsize_derive = {version = "0.1", optional = true}
 rustc-serialize = "0.3"
 serde = {version = "0.8", optional = true}
 serde_derive = {version = "0.8", optional = true}
+url = "1.2"

components/style_traits/cursor.rs

@@ -4,7 +4,7 @@
 
 //! A list of common mouse cursors per CSS3-UI § 8.1.1.
 
-use cssparser::ToCss;
+use super::ToCss;
 
 macro_rules! define_cursor {
     ($( $css: expr => $variant: ident = $value: expr, )+) => {

components/style_traits/lib.rs

@@ -23,6 +23,7 @@ extern crate euclid;
 extern crate rustc_serialize;
 #[cfg(feature = "servo")] extern crate serde;
 #[cfg(feature = "servo")] #[macro_use] extern crate serde_derive;
+extern crate url;
 
 /// Opaque type stored in type-unsafe work queues for parallel layout.
 /// Must be transmutable to and from TNode.
@@ -61,3 +62,4 @@ pub mod cursor;
 pub mod values;
 pub mod viewport;
 
+pub use values::ToCss;

components/style_traits/values.rs

@@ -2,6 +2,60 @@
  * 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 app_units::Au;
+use cssparser::CssStringWriter;
+use std::fmt::{self, Write};
+use url::Url;
+
+/// The real ToCss trait can't be implemented for types in crates that don't
+/// depend on each other.
+pub trait ToCss {
+    /// Serialize `self` in CSS syntax, writing to `dest`.
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write;
+
+    /// Serialize `self` in CSS syntax and return a string.
+    ///
+    /// (This is a convenience wrapper for `to_css` and probably should not be overridden.)
+    #[inline]
+    fn to_css_string(&self) -> String {
+        let mut s = String::new();
+        self.to_css(&mut s).unwrap();
+        s
+    }
+}
+
+impl ToCss for Au {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        write!(dest, "{}px", self.to_f64_px())
+    }
+}
+
+impl ToCss for Url {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        try!(dest.write_str("url(\""));
+        try!(write!(CssStringWriter::new(dest), "{}", self));
+        try!(dest.write_str("\")"));
+        Ok(())
+    }
+}
+
+macro_rules! impl_to_css_for_predefined_type {
+    ($name: ty) => {
+        impl<'a> ToCss for $name {
+            fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+                ::cssparser::ToCss::to_css(self, dest)
+            }
+        }
+    };
+}
+
+impl_to_css_for_predefined_type!(f32);
+impl_to_css_for_predefined_type!(i32);
+impl_to_css_for_predefined_type!(u32);
+impl_to_css_for_predefined_type!(::cssparser::Token<'a>);
+impl_to_css_for_predefined_type!(::cssparser::RGBA);
+impl_to_css_for_predefined_type!(::cssparser::Color);
+
 #[macro_export]
 macro_rules! define_css_keyword_enum {
     ($name: ident: $( $css: expr => $variant: ident ),+,) => {
@@ -50,7 +104,7 @@ macro_rules! __define_css_keyword_enum__actual {
             }
         }
 
-        impl ::cssparser::ToCss for $name {
+        impl ToCss for $name {
             fn to_css<W>(&self, dest: &mut W) -> ::std::fmt::Result
                 where W: ::std::fmt::Write {
                     match *self {
@@ -61,7 +115,6 @@ macro_rules! __define_css_keyword_enum__actual {
     }
 }
 
-
 pub mod specified {
     use app_units::Au;
 

ports/cef/Cargo.lock

@@ -2294,6 +2294,7 @@ dependencies = [
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.8.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 0.8.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

ports/geckolib/Cargo.lock

@@ -373,6 +373,7 @@ dependencies = [
  "cssparser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

ports/geckolib/glue.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
-use cssparser::{Parser, ToCss};
+use cssparser::Parser;
 use env_logger;
 use euclid::Size2D;
 use parking_lot::RwLock;
@@ -46,6 +46,7 @@ use style::sequential;
 use style::string_cache::Atom;
 use style::stylesheets::{Origin, Stylesheet};
 use style::timer::Timer;
+use style_traits::ToCss;
 use url::Url;
 
 /*

ports/geckolib/lib.rs

@@ -12,6 +12,7 @@ extern crate euclid;
 extern crate libc;
 #[macro_use] extern crate log;
 extern crate parking_lot;
+extern crate style_traits;
 extern crate url;
 
 #[allow(non_snake_case)]

tests/unit/style/parsing/basic_shape.rs

@@ -5,6 +5,7 @@
 use parsing::parse;
 use style::parser::Parse;
 use style::values::specified::basic_shape::*;
+use style_traits::ToCss;
 
 // Ensure that basic-shape sub-functions parse as both basic shapes
 // and their individual components
@@ -21,14 +22,14 @@ macro_rules! assert_border_radius_values {
         let input = parse(BorderRadius::parse, $input)
                           .expect(&format!("Failed parsing {} as border radius",
                                   $input));
-        assert_eq!(::cssparser::ToCss::to_css_string(&input.top_left.0.width), $tlw);
+        assert_eq!(::style_traits::ToCss::to_css_string(&input.top_left.0.width), $tlw);
-        assert_eq!(::cssparser::ToCss::to_css_string(&input.top_right.0.width), $trw);
+        assert_eq!(::style_traits::ToCss::to_css_string(&input.top_right.0.width), $trw);
-        assert_eq!(::cssparser::ToCss::to_css_string(&input.bottom_right.0.width), $brw);
+        assert_eq!(::style_traits::ToCss::to_css_string(&input.bottom_right.0.width), $brw);
-        assert_eq!(::cssparser::ToCss::to_css_string(&input.bottom_left.0.width), $blw);
+        assert_eq!(::style_traits::ToCss::to_css_string(&input.bottom_left.0.width), $blw);
-        assert_eq!(::cssparser::ToCss::to_css_string(&input.top_left.0.height), $tlh);
+        assert_eq!(::style_traits::ToCss::to_css_string(&input.top_left.0.height), $tlh);
-        assert_eq!(::cssparser::ToCss::to_css_string(&input.top_right.0.height), $trh);
+        assert_eq!(::style_traits::ToCss::to_css_string(&input.top_right.0.height), $trh);
-        assert_eq!(::cssparser::ToCss::to_css_string(&input.bottom_right.0.height), $brh);
+        assert_eq!(::style_traits::ToCss::to_css_string(&input.bottom_right.0.height), $brh);
-        assert_eq!(::cssparser::ToCss::to_css_string(&input.bottom_left.0.height), $blh);
+        assert_eq!(::style_traits::ToCss::to_css_string(&input.bottom_left.0.height), $blh);
     }
 }
 

tests/unit/style/parsing/font.rs

@@ -9,6 +9,7 @@ use style::properties::longhands::font_feature_settings;
 use style::properties::longhands::font_feature_settings::computed_value;
 use style::properties::longhands::font_feature_settings::computed_value::FeatureTagValue;
 use style::stylesheets::Origin;
+use style_traits::ToCss;
 use url::Url;
 
 #[test]
@@ -100,7 +101,7 @@ fn font_language_override_should_parse_properly() {
 #[test]
 #[should_panic]
 fn font_language_override_should_fail_on_empty_str() {
-    use style::properties::longhands::font_language_override::{self, SpecifiedValue};
+    use style::properties::longhands::font_language_override;
 
     parse_longhand!(font_language_override, "");
 }

tests/unit/style/parsing/image.rs

@@ -7,6 +7,7 @@ use media_queries::CSSErrorReporterTest;
 use style::parser::ParserContext;
 use style::stylesheets::Origin;
 use style::values::specified::image::*;
+use style_traits::ToCss;
 use url::Url;
 
 #[test]

tests/unit/style/parsing/mod.rs

@@ -21,12 +21,12 @@ macro_rules! assert_roundtrip {
     ($fun:expr, $input:expr, $output:expr) => {
         let parsed = $crate::parsing::parse($fun, $input)
                         .expect(&format!("Failed to parse {}", $input));
-        let serialized = ::cssparser::ToCss::to_css_string(&parsed);
+        let serialized = ToCss::to_css_string(&parsed);
         assert_eq!(serialized, $output);
 
         let re_parsed = $crate::parsing::parse($fun, &serialized)
                         .expect(&format!("Failed to parse serialization {}", $input));
-        let re_serialized = ::cssparser::ToCss::to_css_string(&re_parsed);
+        let re_serialized = ToCss::to_css_string(&re_parsed);
         assert_eq!(serialized, re_serialized);
     }
 }
@@ -41,13 +41,13 @@ macro_rules! assert_roundtrip_with_context {
         let mut parser = Parser::new($input);
         let parsed = $fun(&context, &mut parser)
                      .expect(&format!("Failed to parse {}", $input));
-        let serialized = ::cssparser::ToCss::to_css_string(&parsed);
+        let serialized = ToCss::to_css_string(&parsed);
         assert_eq!(serialized, $output);
 
         let mut parser = Parser::new(&serialized);
         let re_parsed = $fun(&context, &mut parser)
                         .expect(&format!("Failed to parse {}", $input));
-        let re_serialized = ::cssparser::ToCss::to_css_string(&re_parsed);
+        let re_serialized = ToCss::to_css_string(&re_parsed);
         assert_eq!(serialized, re_serialized);
     }
 }

tests/unit/style/parsing/position.rs

@@ -4,6 +4,7 @@
 
 use parsing::parse;
 use style::values::specified::position::*;
+use style_traits::ToCss;
 
 #[test]
 fn test_position() {

tests/unit/style/parsing/selectors.rs

@@ -2,7 +2,7 @@
  * 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 cssparser::Parser;
+use cssparser::{Parser, ToCss};
 use selectors::parser::{Selector, ParserContext, parse_selector_list};
 use style::selector_impl::TheSelectorImpl;
 

tests/unit/style/properties/serialization.rs

@@ -2,7 +2,6 @@
  * 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/. */
 
-pub use cssparser::ToCss;
 pub use std::sync::Arc;
 pub use style::computed_values::display::T::inline_block;
 pub use style::properties::{DeclaredValue, PropertyDeclaration, PropertyDeclarationBlock, Importance};
@@ -11,6 +10,7 @@ pub use style::values::specified::{LengthOrPercentage, LengthOrPercentageOrAuto,
 pub use style::properties::longhands::outline_color::computed_value::T as ComputedColor;
 pub use style::values::RGBA;
 pub use style::values::specified::UrlExtraData;
+pub use style_traits::ToCss;
 pub use url::Url;
 
 #[test]

tests/unit/stylo/lib.rs

@@ -11,6 +11,7 @@ extern crate libc;
 #[macro_use] extern crate log;
 extern crate parking_lot;
 extern crate style;
+extern crate style_traits;
 extern crate url;
 
 mod sanity_checks;