script: Fix Servo build.

components/layout_thread/dom_wrapper.rs

@@ -888,6 +888,10 @@ impl<'le> ::selectors::Element for ServoLayoutElement<'le> {
         self.element.namespace()
     }
 
+    fn is_pseudo_element(&self) -> bool {
+        false
+    }
+
     fn match_pseudo_element(
         &self,
         _pseudo: &PseudoElement,
@@ -1394,6 +1398,10 @@ impl<'le> ::selectors::Element for ServoThreadSafeLayoutElement<'le> {
         ::selectors::OpaqueElement::new(unsafe { &*(self.as_node().opaque().0 as *const ()) })
     }
 
+    fn is_pseudo_element(&self) -> bool {
+        false
+    }
+
     fn parent_element(&self) -> Option<Self> {
         warn!("ServoThreadSafeLayoutElement::parent_element called");
         None

components/script/dom/element.rs

@@ -685,9 +685,9 @@ impl LayoutElementHelpers for LayoutDom<Element> {
         if let Some(url) = background {
             hints.push(from_declaration(
                 shared_lock,
-                PropertyDeclaration::BackgroundImage(background_image::SpecifiedValue(vec![
+                PropertyDeclaration::BackgroundImage(background_image::SpecifiedValue(
-                    Either::Second(specified::Image::for_cascade(url.into())),
+                    vec![Either::Second(specified::Image::for_cascade(url.into()))].into(),
-                ])),
+                )),
             ));
         }
 
@@ -2945,6 +2945,10 @@ impl<'a> SelectorsElement for DomRoot<Element> {
         }
     }
 
+    fn is_pseudo_element(&self) -> bool {
+        false
+    }
+
     fn match_pseudo_element(
         &self,
         _pseudo: &PseudoElement,