Bug 793848, faster svg:use check, r=bz , a=lsblakk

layout/base/nsCSSFrameConstructor.cpp

@@ -3912,8 +3912,7 @@ nsCSSFrameConstructor::GetAnonymousContent(nsIContent* aParent,
 
     // least-surprise CSS binding until we do the SVG specified
     // cascading rules for <svg:use> - bug 265894
-    if (aParent &&
-        aParent->NodeInfo()->Equals(nsGkAtoms::use, kNameSpaceID_SVG)) {
+    if (aParentFrame->GetType() == nsGkAtoms::svgUseFrame) {
       content->SetFlags(NODE_IS_ANONYMOUS);
     } else {
       content->SetNativeAnonymous();