1 files changed, 55 insertions, 12 deletions
diff --git a/components/script/dom/stylesheetlist.rs b/components/script/dom/stylesheetlist.rs
index 0b10680f52a..236f1c9cd9a 100644
--- a/components/script/dom/stylesheetlist.rs
+++ b/components/script/dom/stylesheetlist.rs
@@ -5,33 +5,76 @@
 use crate::dom::bindings::codegen::Bindings::StyleSheetListBinding;
 use crate::dom::bindings::codegen::Bindings::StyleSheetListBinding::StyleSheetListMethods;
 use crate::dom::bindings::reflector::{reflect_dom_object, Reflector};
-use crate::dom::bindings::root::DomRoot;
-use crate::dom::bindings::trace::JSTraceable;
+use crate::dom::bindings::root::{Dom, DomRoot};
 use crate::dom::cssstylesheet::CSSStyleSheet;
+use crate::dom::document::Document;
 use crate::dom::element::Element;
+use crate::dom::shadowroot::ShadowRoot;
 use crate::dom::stylesheet::StyleSheet;
 use crate::dom::window::Window;
 use dom_struct::dom_struct;
 use servo_arc::Arc;
 use style::stylesheets::Stylesheet;
 
-pub trait StyleSheetListOwner: JSTraceable {
-    fn stylesheet_count(&self) -> usize;
-    fn stylesheet_at(&self, index: usize) -> Option<DomRoot<CSSStyleSheet>>;
-    fn add_stylesheet(&self, owner: &Element, sheet: Arc<Stylesheet>);
-    fn remove_stylesheet(&self, owner: &Element, s: &Arc<Stylesheet>);
-    fn invalidate_stylesheets(&self);
+#[must_root]
+#[derive(JSTraceable, MallocSizeOf)]
+pub enum StyleSheetListOwner {
+    Document(Dom<Document>),
+    ShadowRoot(Dom<ShadowRoot>),
+}
+
+impl StyleSheetListOwner {
+    pub fn stylesheet_count(&self) -> usize {
+        match *self {
+            StyleSheetListOwner::Document(ref doc) => doc.stylesheet_count(),
+            StyleSheetListOwner::ShadowRoot(ref shadow_root) => shadow_root.stylesheet_count(),
+        }
+    }
+
+    pub fn stylesheet_at(&self, index: usize) -> Option<DomRoot<CSSStyleSheet>> {
+        match *self {
+            StyleSheetListOwner::Document(ref doc) => doc.stylesheet_at(index),
+            StyleSheetListOwner::ShadowRoot(ref shadow_root) => shadow_root.stylesheet_at(index),
+        }
+    }
+
+    pub fn add_stylesheet(&self, owner: &Element, sheet: Arc<Stylesheet>) {
+        match *self {
+            StyleSheetListOwner::Document(ref doc) => doc.add_stylesheet(owner, sheet),
+            StyleSheetListOwner::ShadowRoot(ref shadow_root) => {
+                shadow_root.add_stylesheet(owner, sheet)
+            },
+        }
+    }
+
+    pub fn remove_stylesheet(&self, owner: &Element, s: &Arc<Stylesheet>) {
+        match *self {
+            StyleSheetListOwner::Document(ref doc) => doc.remove_stylesheet(owner, s),
+            StyleSheetListOwner::ShadowRoot(ref shadow_root) => {
+                shadow_root.remove_stylesheet(owner, s)
+            },
+        }
+    }
+
+    pub fn invalidate_stylesheets(&self) {
+        match *self {
+            StyleSheetListOwner::Document(ref doc) => doc.invalidate_stylesheets(),
+            StyleSheetListOwner::ShadowRoot(ref shadow_root) => {
+                shadow_root.invalidate_stylesheets()
+            },
+        }
+    }
 }
 
 #[dom_struct]
 pub struct StyleSheetList {
     reflector_: Reflector,
-    #[ignore_malloc_size_of = "trait object"]
-    document_or_shadow_root: Box<StyleSheetListOwner>,
+    document_or_shadow_root: StyleSheetListOwner,
 }
 
 impl StyleSheetList {
-    fn new_inherited(doc_or_sr: Box<StyleSheetListOwner>) -> StyleSheetList {
+    #[allow(unrooted_must_root)]
+    fn new_inherited(doc_or_sr: StyleSheetListOwner) -> StyleSheetList {
         StyleSheetList {
             reflector_: Reflector::new(),
             document_or_shadow_root: doc_or_sr,
@@ -39,7 +82,7 @@ impl StyleSheetList {
     }
 
     #[allow(unrooted_must_root)]
-    pub fn new(window: &Window, doc_or_sr: Box<StyleSheetListOwner>) -> DomRoot<StyleSheetList> {
+    pub fn new(window: &Window, doc_or_sr: StyleSheetListOwner) -> DomRoot<StyleSheetList> {
         reflect_dom_object(
             Box::new(StyleSheetList::new_inherited(doc_or_sr)),
             window,