--- a/dom/html/HTMLSourceElement.cpp
+++ b/dom/html/HTMLSourceElement.cpp
@@ -70,31 +70,32 @@ HTMLSourceElement::WouldMatchMediaForDoc
 {
   if (aMedia.IsEmpty()) {
     return true;
   }
 
   nsIPresShell* presShell = aDocument->GetShell();
   nsPresContext* pctx = presShell ? presShell->GetPresContext() : nullptr;
 
-  RefPtr<MediaList> mediaList = MediaList::Create(*aDocument, aMedia);
+  RefPtr<MediaList> mediaList =
+    MediaList::Create(aDocument->GetStyleBackendType(), aMedia);
   return pctx && mediaList->Matches(*pctx, nullptr);
 }
 
 void
 HTMLSourceElement::UpdateMediaList(const nsAttrValue* aValue)
 {
   mMediaList = nullptr;
   nsString mediaStr;
   if (!aValue || (mediaStr = aValue->GetStringValue()).IsEmpty()) {
     return;
   }
 
   nsCSSParser cssParser;
-  mMediaList = MediaList::Create(*OwnerDoc(), mediaStr);
+  mMediaList = MediaList::Create(OwnerDoc()->GetStyleBackendType(), mediaStr);
 }
 
 nsresult
 HTMLSourceElement::AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                                 const nsAttrValue* aValue, bool aNotify)
 {
   // If we are associated with a <picture> with a valid <img>, notify it of
   // responsive parameter changes

--- a/layout/style/MediaList.cpp
+++ b/layout/style/MediaList.cpp
@@ -67,25 +67,17 @@ MediaList::DoMediaChange(Func aCallback)
   /* XXXldb Pass something meaningful? */
   if (doc) {
     doc->StyleRuleChanged(mStyleSheet, nullptr);
   }
   return rv;
 }
 
 /* static */ already_AddRefed<MediaList>
-MediaList::Create(const nsIDocument& aDocument,
-                  const nsAString& aMedia)
-{
-  return Create(aDocument.GetStyleBackendType(), aMedia);
-}
-
-/* static */ already_AddRefed<MediaList>
-MediaList::Create(StyleBackendType aBackendType,
-                  const nsAString& aMedia)
+MediaList::Create(StyleBackendType aBackendType, const nsAString& aMedia)
 {
   if (aBackendType == StyleBackendType::Servo) {
     RefPtr<ServoMediaList> mediaList = new ServoMediaList(aMedia);
     return mediaList.forget();
   }
 
   nsCSSParser parser;
   RefPtr<nsMediaList> mediaList = new nsMediaList();

--- a/layout/style/MediaList.h
+++ b/layout/style/MediaList.h
@@ -41,29 +41,16 @@ public:
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(MediaList)
 
   /**
    * 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.
-   */
-  static already_AddRefed<MediaList> Create(const nsIDocument& aDocument,
-                                            const nsAString& aMedia);
-
   virtual already_AddRefed<MediaList> Clone() = 0;
 
   JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) final;
   nsISupports* GetParentObject() const { return nullptr; }
 
   virtual void GetText(nsAString& aMediaText) = 0;
   virtual void SetText(const nsAString& aMediaText) = 0;
   virtual bool Matches(nsPresContext& aPresContext,

--- a/layout/style/StyleSheet.cpp
+++ b/layout/style/StyleSheet.cpp
@@ -686,17 +686,17 @@ StyleSheet::DropMedia()
     mMedia = nullptr;
   }
 }
 
 dom::MediaList*
 StyleSheet::Media()
 {
   if (!mMedia) {
-    mMedia = dom::MediaList::Create(mType);
+    mMedia = dom::MediaList::Create(mType, nsString());
     mMedia->SetStyleSheet(this);
   }
 
   return mMedia;
 }
 
 // nsWrapperCache