diff --git a/components/style/values/generics/font.rs b/components/style/values/generics/font.rs
index 8fb5e5245dd..d48a0a36bbc 100644
--- a/components/style/values/generics/font.rs
+++ b/components/style/values/generics/font.rs
@@ -186,8 +186,9 @@ impl<Length> SpecifiedValueInfo for KeywordInfo<Length> {
 }
 
 /// CSS font keywords
-#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf, PartialEq,
-         SpecifiedValueInfo, ToAnimatedValue, ToAnimatedZero, ToCss)]
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug, MallocSizeOf,
+         Parse, PartialEq, SpecifiedValueInfo, ToAnimatedValue, ToAnimatedZero,
+         ToCss)]
 #[allow(missing_docs)]
 pub enum KeywordSize {
     #[css(keyword = "xx-small")]
diff --git a/components/style/values/specified/font.rs b/components/style/values/specified/font.rs
index 7f971f36fcf..fedf748d54f 100644
--- a/components/style/values/specified/font.rs
+++ b/components/style/values/specified/font.rs
@@ -715,21 +715,6 @@ impl KeywordInfo {
     }
 }
 
-impl KeywordSize {
-    /// Parses a keyword size.
-    pub fn parse<'i, 't>(input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
-        try_match_ident_ignore_ascii_case! { input,
-            "xx-small" => Ok(KeywordSize::XXSmall),
-            "x-small" => Ok(KeywordSize::XSmall),
-            "small" => Ok(KeywordSize::Small),
-            "medium" => Ok(KeywordSize::Medium),
-            "large" => Ok(KeywordSize::Large),
-            "x-large" => Ok(KeywordSize::XLarge),
-            "xx-large" => Ok(KeywordSize::XXLarge),
-        }
-    }
-}
-
 /// This is the ratio applied for font-size: larger
 /// and smaller by both Firefox and Chrome
 const LARGER_FONT_SIZE_RATIO: f32 = 1.2;
diff --git a/components/style_derive/parse.rs b/components/style_derive/parse.rs
index 620ba3fee82..7727d6b89bb 100644
--- a/components/style_derive/parse.rs
+++ b/components/style_derive/parse.rs
@@ -20,6 +20,10 @@ pub fn derive(input: DeriveInput) -> Tokens {
         );
 
         let variant_attrs = cg::parse_variant_attrs_from_ast::<CssVariantAttrs>(&variant.ast());
+        if variant_attrs.skip {
+            return match_body;
+        }
+
         let identifier = cg::to_css_identifier(
             &variant_attrs.keyword.unwrap_or(variant.ast().ident.as_ref().into()),
         );