diff --git a/components/style/values/animated/effects.rs b/components/style/values/animated/effects.rs
index 4e3aeb4fde8..c1ce7fd6bed 100644
--- a/components/style/values/animated/effects.rs
+++ b/components/style/values/animated/effects.rs
@@ -13,7 +13,7 @@ use values::Impossible;
 use values::animated::{Animate, Procedure, ToAnimatedValue, ToAnimatedZero};
 use values::animated::color::RGBA;
 use values::computed::{Angle, Number};
-use values::computed::length::{Length, NonNegativeLength};
+use values::computed::length::Length;
 use values::distance::{ComputeSquaredDistance, SquaredDistance};
 use values::generics::effects::BoxShadow as GenericBoxShadow;
 use values::generics::effects::Filter as GenericFilter;
@@ -33,7 +33,7 @@ pub type TextShadowList = ShadowList<SimpleShadow>;
 pub struct ShadowList<Shadow>(Vec<Shadow>);
 
 /// An animated value for a single `box-shadow`.
-pub type BoxShadow = GenericBoxShadow<Option<RGBA>, Length, NonNegativeLength, Length>;
+pub type BoxShadow = GenericBoxShadow<Option<RGBA>, Length, Length, Length>;
 
 /// An animated value for the `filter` property.
 #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
@@ -42,14 +42,14 @@ pub struct FilterList(pub Vec<Filter>);
 
 /// An animated value for a single `filter`.
 #[cfg(feature = "gecko")]
-pub type Filter = GenericFilter<Angle, Number, NonNegativeLength, SimpleShadow>;
+pub type Filter = GenericFilter<Angle, Number, Length, SimpleShadow>;
 
 /// An animated value for a single `filter`.
 #[cfg(not(feature = "gecko"))]
-pub type Filter = GenericFilter<Angle, Number, NonNegativeLength, Impossible>;
+pub type Filter = GenericFilter<Angle, Number, Length, Impossible>;
 
 /// An animated value for the `drop-shadow()` filter.
-pub type SimpleShadow = GenericSimpleShadow<Option<RGBA>, Length, NonNegativeLength>;
+pub type SimpleShadow = GenericSimpleShadow<Option<RGBA>, Length, Length>;
 
 impl ToAnimatedValue for ComputedBoxShadowList {
     type AnimatedValue = BoxShadowList;
diff --git a/components/style/values/animated/mod.rs b/components/style/values/animated/mod.rs
index a118292dd98..04bab7375f1 100644
--- a/components/style/values/animated/mod.rs
+++ b/components/style/values/animated/mod.rs
@@ -17,7 +17,6 @@ use values::computed::BorderCornerRadius as ComputedBorderCornerRadius;
 use values::computed::ComputedUrl;
 use values::computed::MaxLength as ComputedMaxLength;
 use values::computed::MozLength as ComputedMozLength;
-use values::computed::NonNegativeLength as ComputedNonNegativeLength;
 use values::specified::url::SpecifiedUrl;
 
 pub mod color;
@@ -261,20 +260,6 @@ trivial_to_animated_value!(ComputedUrl);
 trivial_to_animated_value!(bool);
 trivial_to_animated_value!(f32);
 
-impl ToAnimatedValue for ComputedNonNegativeLength {
-    type AnimatedValue = Self;
-
-    #[inline]
-    fn to_animated_value(self) -> Self {
-        self
-    }
-
-    #[inline]
-    fn from_animated_value(animated: Self::AnimatedValue) -> Self {
-        ComputedNonNegativeLength::new(animated.px().max(0.))
-    }
-}
-
 impl ToAnimatedValue for ComputedBorderCornerRadius {
     type AnimatedValue = Self;
 
diff --git a/components/style/values/computed/length.rs b/components/style/values/computed/length.rs
index 8c00d330222..b482c8aeb17 100644
--- a/components/style/values/computed/length.rs
+++ b/components/style/values/computed/length.rs
@@ -815,6 +815,20 @@ pub type LengthOrNormal = Either<Length, Normal>;
 /// A wrapper of Length, whose value must be >= 0.
 pub type NonNegativeLength = NonNegative<Length>;
 
+impl ToAnimatedValue for NonNegativeLength {
+    type AnimatedValue = Length;
+
+    #[inline]
+    fn to_animated_value(self) -> Self::AnimatedValue {
+        self.0
+    }
+
+    #[inline]
+    fn from_animated_value(animated: Self::AnimatedValue) -> Self {
+        NonNegativeLength::new(animated.px().max(0.))
+    }
+}
+
 impl NonNegativeLength {
     /// Create a NonNegativeLength.
     #[inline]