diff --git a/components/style/properties/longhand/counters.mako.rs b/components/style/properties/longhand/counters.mako.rs
index 190351895c7..16aca0ff60f 100644
--- a/components/style/properties/longhand/counters.mako.rs
+++ b/components/style/properties/longhand/counters.mako.rs
@@ -8,7 +8,6 @@
 
 <%helpers:longhand name="content" boxed="True" animation_value_type="discrete"
                    spec="https://drafts.csswg.org/css-content/#propdef-content">
-    use values::computed::ComputedValueAsSpecified;
     #[cfg(feature = "gecko")]
     use values::generics::CounterStyleOrNone;
     #[cfg(feature = "gecko")]
@@ -22,8 +21,6 @@
     pub use self::computed_value::T as SpecifiedValue;
     pub use self::computed_value::ContentItem;
 
-    impl ComputedValueAsSpecified for SpecifiedValue {}
-
     pub mod computed_value {
         use cssparser;
         use std::fmt;
@@ -39,8 +36,8 @@
         #[cfg(feature = "gecko")]
         use values::specified::Attr;
 
-        #[derive(Clone, Debug, Eq, PartialEq)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, Eq, PartialEq, ToComputedValue)]
         pub enum ContentItem {
             /// Literal string content.
             String(String),
@@ -100,8 +97,8 @@
             }
         }
 
-        #[derive(Clone, Debug, Eq, PartialEq)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+        #[derive(Clone, Debug, Eq, PartialEq, ToComputedValue)]
         pub enum T {
             Normal,
             None,