--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -10084,47 +10084,37 @@ nsIDocument::CreateStaticClone(nsIDocShe
 
       clonedDoc->mOriginalDocument->mStaticCloneCount++;
 
       int32_t sheetsCount = GetNumberOfStyleSheets();
       for (int32_t i = 0; i < sheetsCount; ++i) {
         RefPtr<StyleSheet> sheet = GetStyleSheetAt(i);
         if (sheet) {
           if (sheet->IsApplicable()) {
-            // XXXheycam Need to make ServoStyleSheet cloning work.
-            if (sheet->IsGecko()) {
-              RefPtr<StyleSheet> clonedSheet =
-                sheet->Clone(nullptr, nullptr, clonedDoc, nullptr);
-              NS_WARNING_ASSERTION(clonedSheet,
-                                   "Cloning a stylesheet didn't work!");
-              if (clonedSheet) {
-                clonedDoc->AddStyleSheet(clonedSheet);
-              }
-            } else {
-              NS_ERROR("stylo: ServoStyleSheet doesn't support cloning");
+            RefPtr<StyleSheet> clonedSheet =
+              sheet->Clone(nullptr, nullptr, clonedDoc, nullptr);
+            NS_WARNING_ASSERTION(clonedSheet,
+                                 "Cloning a stylesheet didn't work!");
+            if (clonedSheet) {
+              clonedDoc->AddStyleSheet(clonedSheet);
             }
           }
         }
       }
 
       // Iterate backwards to maintain order
       for (StyleSheet* sheet : Reversed(thisAsDoc->mOnDemandBuiltInUASheets)) {
         if (sheet) {
           if (sheet->IsApplicable()) {
-            // XXXheycam Need to make ServoStyleSheet cloning work.
-            if (sheet->IsGecko()) {
-              RefPtr<StyleSheet> clonedSheet =
-                sheet->Clone(nullptr, nullptr, clonedDoc, nullptr);
-              NS_WARNING_ASSERTION(clonedSheet,
-                                   "Cloning a stylesheet didn't work!");
-              if (clonedSheet) {
-                clonedDoc->AddOnDemandBuiltInUASheet(clonedSheet);
-              }
-            } else {
-              NS_ERROR("stylo: ServoStyleSheet doesn't support cloning");
+            RefPtr<StyleSheet> clonedSheet =
+              sheet->Clone(nullptr, nullptr, clonedDoc, nullptr);
+            NS_WARNING_ASSERTION(clonedSheet,
+                                 "Cloning a stylesheet didn't work!");
+            if (clonedSheet) {
+              clonedDoc->AddOnDemandBuiltInUASheet(clonedSheet);
             }
           }
         }
       }
     }
   }
   mCreatingStaticClone = false;
   return clonedDoc.forget();