--- a/servo/components/style/gecko/url.rs
+++ b/servo/components/style/gecko/url.rs
@@ -3,16 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 //! Common handling for the specified value CSS url() values.
 
 use cssparser::CssStringWriter;
 use gecko_bindings::structs::{ServoBundledURI, URLExtraData};
 use gecko_bindings::structs::root::mozilla::css::ImageValue;
 use gecko_bindings::sugar::refptr::RefPtr;
+use gecko_bindings::structs::mozilla::css::URLValueData;
 use parser::ParserContext;
 use std::borrow::Cow;
 use std::fmt::{self, Write};
 use style_traits::{ToCss, ParseError};
 use stylearc::Arc;
 
 /// A specified url() value for gecko. Gecko does not eagerly resolve SpecifiedUrls.
 #[derive(Clone, Debug, PartialEq)]
@@ -48,16 +49,26 @@ impl SpecifiedUrl {
 
     /// Returns true if the URL is definitely invalid. We don't eagerly resolve
     /// URLs in gecko, so we just return false here.
     /// use its |resolved| status.
     pub fn is_invalid(&self) -> bool {
         false
     }
 
+    /// Convert from URLValueData to SpecifiedUrl.
+    pub unsafe fn from_url_value_data(url: &URLValueData)
+                                       -> Result<SpecifiedUrl, ()> {
+        Ok(SpecifiedUrl {
+            serialization: Arc::new(url.mString.to_string()),
+            extra_data: url.mExtraData.to_safe(),
+            image_value: None,
+        })
+    }
+
     /// Returns true if this URL looks like a fragment.
     /// See https://drafts.csswg.org/css-values/#local-urls
     pub fn is_fragment(&self) -> bool {
         self.as_str().chars().next().map_or(false, |c| c == '#')
     }
 
     /// Return the resolved url as string, or the empty string if it's invalid.
     ///