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

Source/core/testing/Internals.cpp

Index: Source/core/testing/Internals.cpp
diff --git a/Source/core/testing/Internals.cpp b/Source/core/testing/Internals.cpp
index 15d1d3ffe345cb8a806c76a6812c608d5fa43e75..f8231193674a86667f16c204503392505660193a 100644
--- a/Source/core/testing/Internals.cpp
+++ b/Source/core/testing/Internals.cpp
@@ -1542,6 +1542,54 @@ String Internals::layerTreeAsText(Document* document, ExceptionCode& ec) const
     return layerTreeAsText(document, 0, ec);
 }
 
+PassRefPtr<NodeList> Internals::paintOrderListBeforePromote(Element* element, ExceptionCode& ec)
+{
+    if (!element) {
+        ec = INVALID_ACCESS_ERR;
+        return 0;
+    }
+
+    element->document()->updateLayout();
+
+    RenderObject* renderer = element->renderer();
+    if (!renderer || !renderer->isBox()) {
+        ec = INVALID_ACCESS_ERR;
+        return 0;
+    }
+
+    RenderLayer* layer = toRenderBox(renderer)->layer();
+    if (!layer) {
+        ec = INVALID_ACCESS_ERR;
+        return 0;
+    }
+
+    return layer->paintOrderListBeforePromote();
+}
+
+PassRefPtr<NodeList> Internals::paintOrderListAfterPromote(Element* element, ExceptionCode& ec)
+{
+    if (!element) {
+        ec = INVALID_ACCESS_ERR;
+        return 0;
+    }
+
+    element->document()->updateLayout();
+
+    RenderObject* renderer = element->renderer();
+    if (!renderer || !renderer->isBox()) {
+        ec = INVALID_ACCESS_ERR;
+        return 0;
+    }
+
+    RenderLayer* layer = toRenderBox(renderer)->layer();
+    if (!layer) {
+        ec = INVALID_ACCESS_ERR;
+        return 0;
+    }
+
+    return layer->paintOrderListAfterPromote();
+}
+
 String Internals::layerTreeAsText(Document* document, unsigned flags, ExceptionCode& ec) const
 {
     if (!document || !document->frame()) {