2 files changed, 11 insertions, 0 deletions
diff --git a/components/style/author_styles.rs b/components/style/author_styles.rs
index 37eb68ff4f7..eff64ed6c1e 100644
--- a/components/style/author_styles.rs
+++ b/components/style/author_styles.rs
@@ -18,6 +18,7 @@ use crate::stylist::CascadeData;
 
 /// A set of author stylesheets and their computed representation, such as the
 /// ones used for ShadowRoot and XBL.
+#[derive(MallocSizeOf)]
 pub struct AuthorStyles<S>
 where
     S: StylesheetInDocument + PartialEq + 'static,
diff --git a/components/style/stylesheet_set.rs b/components/style/stylesheet_set.rs
index 409978c3a9e..d2c3ad0f88e 100644
--- a/components/style/stylesheet_set.rs
+++ b/components/style/stylesheet_set.rs
@@ -585,6 +585,16 @@ where
         self.collection.len() == 0
     }
 
+    /// Returns the `index`th stylesheet in the collection of author styles if present.
+    pub fn get(&self, index: usize) -> Option<&S> {
+        self.collection.get(index)
+    }
+
+    /// Returns the number of author stylesheets.
+    pub fn len(&self) -> usize {
+        self.collection.len()
+    }
+
     fn collection_for(
         &mut self,
         _sheet: &S,