Add context-{fill,stroke}-opacity support to {fill,stroke}-opacity.

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

@@ -46,7 +46,7 @@ use values::computed::{LengthOrPercentage, MaxLength, MozLength, Percentage, ToC
 use values::generics::border::BorderCornerRadius as GenericBorderCornerRadius;
 use values::generics::effects::Filter;
 use values::generics::position as generic_position;
-use values::generics::svg::{SVGLength, SVGPaint, SVGPaintKind, SVGStrokeDashArray};
+use values::generics::svg::{SVGLength, SVGOpacity, SVGPaint, SVGPaintKind, SVGStrokeDashArray};
 
 /// A trait used to implement various procedures used during animation.
 pub trait Animatable: Sized {
@@ -3116,6 +3116,45 @@ impl<LengthType> ToAnimatedZero for SVGStrokeDashArray<LengthType>
     }
 }
 
+impl<OpacityType> Animatable for SVGOpacity<OpacityType>
+    where OpacityType: Animatable + Clone
+{
+    #[inline]
+    fn add_weighted(&self, other: &Self, self_portion: f64, other_portion: f64) -> Result<Self, ()> {
+        match (self, other) {
+            (&SVGOpacity::Opacity(ref this), &SVGOpacity::Opacity(ref other)) => {
+                this.add_weighted(other, self_portion, other_portion).map(SVGOpacity::Opacity)
+            }
+            _ => {
+                Ok(if self_portion > other_portion { self.clone() } else { other.clone() })
+            }
+        }
+    }
+
+    #[inline]
+    fn compute_distance(&self, other: &Self) -> Result<f64, ()> {
+        match (self, other) {
+            (&SVGOpacity::Opacity(ref this), &SVGOpacity::Opacity(ref other)) => {
+                this.compute_distance(other)
+            }
+            _ => Err(())
+        }
+    }
+}
+
+impl<OpacityType> ToAnimatedZero for SVGOpacity<OpacityType>
+    where OpacityType: ToAnimatedZero + Clone
+{
+    #[inline]
+    fn to_animated_zero(&self) -> Result<Self, ()> {
+        match self {
+            &SVGOpacity::Opacity(ref opacity) =>
+                opacity.to_animated_zero().map(SVGOpacity::Opacity),
+            other => Ok(other.clone()),
+        }
+    }
+}
+
 <%
     FILTER_FUNCTIONS = [ 'Blur', 'Brightness', 'Contrast', 'Grayscale',
                          'HueRotate', 'Invert', 'Opacity', 'Saturate',