Bug 1471095. Don't do extra work we don't need to in ReparentWrappersInSubtree. r=smaug

dom/base/nsINode.cpp

@@ -1313,18 +1313,6 @@ ReparentWrappersInSubtree(nsIContent* aRoot)
 
   JSContext* cx = jsapi.cx();
 
-  nsIGlobalObject* docGlobal = aRoot->OwnerDoc()->GetScopeObject();
-  if (NS_WARN_IF(!docGlobal)) {
-    return NS_ERROR_UNEXPECTED;
-  }
-
-  JS::Rooted<JSObject*> rootedGlobal(cx, docGlobal->GetGlobalJSObject());
-  if (NS_WARN_IF(!rootedGlobal)) {
-    return NS_ERROR_UNEXPECTED;
-  }
-
-  rootedGlobal = xpc::GetXBLScope(cx, rootedGlobal);
-
   ErrorResult rv;
   JS::Rooted<JSObject*> reflector(cx);
   for (nsIContent* cur = aRoot; cur; cur = cur->GetNextNode(aRoot)) {

layout/base/nsCSSFrameConstructor.cpp

@@ -1916,6 +1916,11 @@ nsCSSFrameConstructor::CreateGeneratedContentItem(nsFrameConstructorState& aStat
       CreateGeneratedContent(aState, aParentContent, pseudoComputedStyle,
                              contentIndex);
     if (content) {
+      // We don't strictly have to set NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE
+      // here; it would get set under AppendChildTo.  But AppendChildTo might
+      // think that we're going from not being anonymous to being anonymous and
+      // do some extra work; setting the flag here avoids that.
+      content->SetFlags(NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE);
       container->AppendChildTo(content, false);
       if (content->IsElement()) {
         // If we created any children elements, Servo needs to traverse them, but