Add an intermediate function to generate 2 paint-order lists.

Source/WebCore/dom/PaintOrderLists.h

Index: Source/WebCore/dom/PaintOrderLists.h
diff --git a/Source/WebCore/dom/PaintOrderLists.h b/Source/WebCore/dom/PaintOrderLists.h
new file mode 100644
index 0000000000000000000000000000000000000000..f1f61623491400fe57932dc9c9458b691ab99915
--- /dev/null
+++ b/Source/WebCore/dom/PaintOrderLists.h
@@ -0,0 +1,23 @@
+#ifndef PaintOrderLists_h
+#define PaintOrderLists_h
+
+#include "ScriptWrappable.h"
+#include <wtf/RefCounted.h>
+
+namespace WebCore {
+
+class PaintOrderLists : public ScriptWrappable, public RefCounted<PaintOrderLists> {
+public:
+    PaintOrderLists(PassRefPtr<NodeList> listBeforePromote, PassRefPtr<NodeList> listAfterPromote) : m_listBeforePromote(listBeforePromote), m_listAfterPromote(listAfterPromote) { }
+
+    // DOM methods & attributes for NodeList
+    PassRefPtr<NodeList> listBeforePromote() const { return m_listBeforePromote; }
+    PassRefPtr<NodeList> listAfterPromote() const { return m_listAfterPromote; }
+
+    PassRefPtr<NodeList> m_listBeforePromote;
+    PassRefPtr<NodeList> m_listAfterPromote;
+};
+
+} // namespace WebCore
+
+#endif // PaintOrderLists_h