another try to optimize

Author: rbri

src/main/java/org/htmlunit/html/DomNode.java

@@ -1047,10 +1047,13 @@ private void fireAddition(final DomNode domNode) {
 
             // a node that is already "complete" (ie not being parsed) and not yet attached
             if (!domNode.isBodyParsed() && !wasAlreadyAttached) {
-                for (final Iterator<DomNode> iterator = domNode.new DescendantDomNodesIterator(); iterator.hasNext();) {
-                    final DomNode child = iterator.next();
-                    child.attachedToPage_ = true;
-                    child.onAllChildrenAddedToPage(true);
+                if (domNode.getFirstChild() != null) {
+                    for (final Iterator<DomNode> iterator =
+                            domNode.new DescendantDomNodesIterator(); iterator.hasNext();) {
+                        final DomNode child = iterator.next();
+                        child.attachedToPage_ = true;
+                        child.onAllChildrenAddedToPage(true);
+                    }
                 }
                 domNode.onAllChildrenAddedToPage(true);
             }

src/main/java/org/htmlunit/html/HtmlPage.java

@@ -1745,11 +1745,13 @@ void notifyNodeAdded(final DomNode node) {
                 frameElements_.add((BaseFrameElement) node);
             }
 
-            for (final Iterator<HtmlElement> iterator = node.new DescendantHtmlElementsIterator();
-                    iterator.hasNext();) {
-                final HtmlElement child = iterator.next();
-                if (child instanceof BaseFrameElement) {
-                    frameElements_.add((BaseFrameElement) child);
+            if (node.getFirstChild() != null) {
+                for (final Iterator<HtmlElement> iterator = node.new DescendantHtmlElementsIterator();
+                        iterator.hasNext();) {
+                    final HtmlElement child = iterator.next();
+                    if (child instanceof BaseFrameElement) {
+                        frameElements_.add((BaseFrameElement) child);
+                    }
                 }
             }