style: Ditch GeckoStyleCoordHelpers, and implement directly on nsStyleCoord.

components/style/gecko/conversions.rs

@@ -9,7 +9,7 @@
 #![allow(unsafe_code)]
 
 use app_units::Au;
-use gecko::values::{convert_rgba_to_nscolor, StyleCoordHelpers};
+use gecko::values::convert_rgba_to_nscolor;
 use gecko_bindings::bindings::{Gecko_CreateGradient, Gecko_SetGradientImageValue, Gecko_SetUrlImageValue};
 use gecko_bindings::bindings::{RawServoStyleSheet, RawServoDeclarationBlock, RawServoStyleRule, RawServoImportRule};
 use gecko_bindings::bindings::{ServoComputedValues, ServoCssRules};

components/style/gecko/values.rs

@@ -14,22 +14,22 @@ use values::computed::{Angle, LengthOrPercentageOrNone, Number};
 use values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto};
 use values::computed::basic_shape::ShapeRadius;
 
-pub trait StyleCoordHelpers {
+/// A trait that defines an interface to convert from and to `nsStyleCoord`s.
-    fn set<T: GeckoStyleCoordConvertible>(&mut self, val: T);
+pub trait GeckoStyleCoordConvertible : Sized {
+    /// Convert this to a `nsStyleCoord`.
+    fn to_gecko_style_coord<T: CoordDataMut>(&self, coord: &mut T);
+    /// Given a `nsStyleCoord`, try to get a value of this type..
+    fn from_gecko_style_coord<T: CoordData>(coord: &T) -> Option<Self>;
 }
 
-impl StyleCoordHelpers for nsStyleCoord {
+impl nsStyleCoord {
     #[inline]
-    fn set<T: GeckoStyleCoordConvertible>(&mut self, val: T) {
+    /// Set this `nsStyleCoord` value to `val`.
+    pub fn set<T: GeckoStyleCoordConvertible>(&mut self, val: T) {
         val.to_gecko_style_coord(self);
     }
 }
 
-pub trait GeckoStyleCoordConvertible : Sized {
-    fn to_gecko_style_coord<T: CoordDataMut>(&self, coord: &mut T);
-    fn from_gecko_style_coord<T: CoordData>(coord: &T) -> Option<Self>;
-}
-
 impl<A: GeckoStyleCoordConvertible, B: GeckoStyleCoordConvertible> GeckoStyleCoordConvertible for Either<A, B> {
     fn to_gecko_style_coord<T: CoordDataMut>(&self, coord: &mut T) {
         match *self {

components/style/properties/gecko.mako.rs

@@ -48,7 +48,6 @@ use gecko::values::convert_nscolor_to_rgba;
 use gecko::values::convert_rgba_to_nscolor;
 use gecko::values::GeckoStyleCoordConvertible;
 use gecko::values::round_border_to_device_pixels;
-use gecko::values::StyleCoordHelpers;
 use logical_geometry::WritingMode;
 use properties::longhands;
 use std::fmt::{self, Debug};