--- a/layout/style/Loader.cpp
+++ b/layout/style/Loader.cpp
@@ -1407,20 +1407,20 @@ Loader::InsertChildSheet(StyleSheet* aSh
                          ImportRule* aGeckoParentRule,
                          const RawServoStyleSheet* aServoChildSheet)
 {
   LOG(("css::Loader::InsertChildSheet"));
   MOZ_ASSERT(aSheet, "Nothing to insert");
   MOZ_ASSERT(aParentSheet, "Need a parent to insert into");
   MOZ_ASSERT_IF(aSheet->IsGecko(), aGeckoParentRule && !aServoChildSheet);
   MOZ_ASSERT_IF(aSheet->IsServo(), aServoChildSheet && !aGeckoParentRule);
+  // child sheets should always start out enabled, even if they got
+  // cloned off of top-level sheets which were disabled
+  aSheet->SetEnabled(true);
   if (aSheet->IsGecko()) {
-    // child sheets should always start out enabled, even if they got
-    // cloned off of top-level sheets which were disabled
-    aSheet->AsGecko()->SetEnabled(true);
     aGeckoParentRule->SetSheet(aSheet->AsGecko()); // This sets the ownerRule on the sheet
   } else {
     if (!aSheet->AsServo()->RawSheet()) {
       aSheet->AsServo()->SetSheetForImport(aServoChildSheet);
     }
   }
   aParentSheet->PrependStyleSheet(aSheet);
 
@@ -1895,18 +1895,17 @@ Loader::DoSheetComplete(SheetLoadData* a
 
   // Go through and deal with the whole linked list.
   SheetLoadData* data = aLoadData;
   while (data) {
     if (!data->mSheetAlreadyComplete) {
       // If mSheetAlreadyComplete, then the sheet could well be modified between
       // when we posted the async call to SheetComplete and now, since the sheet
       // was page-accessible during that whole time.
-      MOZ_ASSERT(!(data->mSheet->IsGecko() &&
-                   data->mSheet->AsGecko()->IsModified()),
+      MOZ_ASSERT(!data->mSheet->IsModified(),
                  "should not get marked modified during parsing");
       data->mSheet->SetComplete();
       data->ScheduleLoadEventIfNeeded(aStatus);
     }
     if (data->mMustNotify && (data->mObserver || !mObservers.IsEmpty())) {
       // Don't notify here so we don't trigger script.  Remember the
       // info we need to notify, then do it later when it's safe.
       aDatasToNotify.AppendElement(data);