Bug 499134 - Crash with DOM Inspector [@ inDOMView::AttributeChanged(nsIDocument*, nsIContent*, int, nsIAtom*, int, unsigned int) ]. r=neil

layout/inspector/src/inDOMView.cpp

@@ -758,7 +758,8 @@ inDOMView::AttributeChanged(nsIDocument *aDocument, nsIContent* aContent,
     inDOMViewNode* insertNode = nsnull;
     RowToNode(attrRow, &insertNode);
     if (insertNode) {
-      if (insertNode->level <= contentNode->level) {
+      if (contentNode &&
+          insertNode->level <= contentNode->level) {
         RowToNode(attrRow-1, &insertNode);
         InsertLinkAfter(newNode, insertNode);
       } else