diff --git a/layout/style/MediaList.h b/layout/style/MediaList.h
index c31fd887f146..99370dbd9a55 100644
--- a/layout/style/MediaList.h
+++ b/layout/style/MediaList.h
@@ -41,11 +41,18 @@ public:
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(MediaList)
 
   /**
-   * Creates a MediaList backed by the StyleBackendType of the document.
+   * Creates a MediaList backed by the given StyleBackendType.
    */
   static already_AddRefed<MediaList> Create(StyleBackendType,
                                             const nsAString& aMedia);
 
+  /**
+   * Creates a MediaList backed by the given StyleBackendType.
+   */
+  static already_AddRefed<MediaList> Create(StyleBackendType aBackendType) {
+    return Create(aBackendType, nsString());
+  }
+
   /**
    * Creates a MediaList backed by the StyleBackendType of the document.
    */
diff --git a/layout/style/StyleSheet.cpp b/layout/style/StyleSheet.cpp
index dadb6b14f4b1..9cea71c88043 100644
--- a/layout/style/StyleSheet.cpp
+++ b/layout/style/StyleSheet.cpp
@@ -14,7 +14,6 @@
 #include "mozilla/CSSStyleSheet.h"
 
 #include "mozAutoDocUpdate.h"
-#include "nsMediaList.h"
 #include "NullPrincipal.h"
 
 namespace mozilla {
@@ -692,7 +691,7 @@ dom::MediaList*
 StyleSheet::Media()
 {
   if (!mMedia) {
-    mMedia = new nsMediaList();
+    mMedia = dom::MediaList::Create(mType);
     mMedia->SetStyleSheet(this);
   }