--- a/dom/base/nsStyleLinkElement.h
+++ b/dom/base/nsStyleLinkElement.h
@@ -34,25 +34,17 @@ class ShadowRoot;
 class nsStyleLinkElement : public nsIStyleSheetLinkingElement
 {
 public:
   nsStyleLinkElement();
   virtual ~nsStyleLinkElement();
 
   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override = 0;
 
-  mozilla::CSSStyleSheet* GetSheet() const
-  {
-    // XXXheycam Return nullptr for ServoStyleSheets until we have a way of
-    // exposing them to script.
-    NS_ASSERTION(!mStyleSheet || mStyleSheet->IsGecko(),
-                 "stylo: ServoStyleSheets can't be exposed to script yet");
-    return mStyleSheet && mStyleSheet->IsGecko() ? mStyleSheet->AsGecko() :
-                                                   nullptr;
-  }
+  mozilla::StyleSheet* GetSheet() const { return mStyleSheet; }
 
   // nsIStyleSheetLinkingElement  
   NS_IMETHOD SetStyleSheet(mozilla::StyleSheet* aStyleSheet) override;
   NS_IMETHOD_(mozilla::StyleSheet*) GetStyleSheet() override;
   NS_IMETHOD InitStyleLinkElement(bool aDontLoadStyle) override;
   NS_IMETHOD UpdateStyleSheet(nsICSSLoaderObserver* aObserver,
                               bool* aWillNotify,
                               bool* aIsAlternate,

--- a/dom/html/HTMLLinkElement.cpp
+++ b/dom/html/HTMLLinkElement.cpp
@@ -90,32 +90,31 @@ NS_INTERFACE_TABLE_HEAD_CYCLE_COLLECTION
 NS_INTERFACE_TABLE_TAIL_INHERITING(nsGenericHTMLElement)
 
 
 NS_IMPL_ELEMENT_CLONE(HTMLLinkElement)
 
 bool
 HTMLLinkElement::Disabled()
 {
-  CSSStyleSheet* ss = GetSheet();
+  StyleSheet* ss = GetSheet();
   return ss && ss->Disabled();
 }
 
 NS_IMETHODIMP
 HTMLLinkElement::GetMozDisabled(bool* aDisabled)
 {
   *aDisabled = Disabled();
   return NS_OK;
 }
 
 void
 HTMLLinkElement::SetDisabled(bool aDisabled)
 {
-  CSSStyleSheet* ss = GetSheet();
-  if (ss) {
+  if (StyleSheet* ss = GetSheet()) {
     ss->SetDisabled(aDisabled);
   }
 }
 
 NS_IMETHODIMP
 HTMLLinkElement::SetMozDisabled(bool aDisabled)
 {
   SetDisabled(aDisabled);

--- a/dom/html/HTMLStyleElement.cpp
+++ b/dom/html/HTMLStyleElement.cpp
@@ -63,32 +63,31 @@ HTMLStyleElement::GetMozDisabled(bool* a
 
   *aDisabled = Disabled();
   return NS_OK;
 }
 
 bool
 HTMLStyleElement::Disabled()
 {
-  CSSStyleSheet* ss = GetSheet();
+  StyleSheet* ss = GetSheet();
   return ss && ss->Disabled();
 }
 
 NS_IMETHODIMP
 HTMLStyleElement::SetMozDisabled(bool aDisabled)
 {
   SetDisabled(aDisabled);
   return NS_OK;
 }
 
 void
 HTMLStyleElement::SetDisabled(bool aDisabled)
 {
-  CSSStyleSheet* ss = GetSheet();
-  if (ss) {
+  if (StyleSheet* ss = GetSheet()) {
     ss->SetDisabled(aDisabled);
   }
 }
 
 NS_IMPL_STRING_ATTR(HTMLStyleElement, Media, media)
 NS_IMPL_BOOL_ATTR(HTMLStyleElement, Scoped, scoped)
 NS_IMPL_STRING_ATTR(HTMLStyleElement, Type, type)