Bug 1379864 - stylo: Remove <style scoped> warning. r=xidorn

MozReview-Commit-ID: 6hUcdLAeaxs

--HG--
extra : rebase_source : c2a38ca757a1864b060fbbb112881dd9806ac46d

dom/base/nsStyleLinkElement.cpp

@@ -427,11 +427,11 @@ nsStyleLinkElement::DoUpdateStyleSheet(nsIDocument* aOldDocument,
     return NS_OK;
   }
 
-  // XXXheycam ServoStyleSheets do not support <style scoped>.
   Element* oldScopeElement = nullptr;
   if (mStyleSheet) {
     if (mStyleSheet->IsServo()) {
-      NS_WARNING("stylo: ServoStyleSheets don't support <style scoped>");
+      MOZ_ASSERT(!aOldDocument->IsScopedStyleEnabled(),
+                 "stylo: ServoStyleSheets don't support <style scoped>");
     } else {
       oldScopeElement = mStyleSheet->AsGecko()->GetScopeElement();
     }