Have ElementTraversal / NodeTraversal's next() methods take a reference

Source/core/editing/SimplifyMarkupCommand.cpp

Index: Source/core/editing/SimplifyMarkupCommand.cpp
diff --git a/Source/core/editing/SimplifyMarkupCommand.cpp b/Source/core/editing/SimplifyMarkupCommand.cpp
index 4e5fdf710612d83040f9f710a477f1bd324b3bf9..8d13312d1e5bc7931bb81ca2cf1e921e31d1eff4 100644
--- a/Source/core/editing/SimplifyMarkupCommand.cpp
+++ b/Source/core/editing/SimplifyMarkupCommand.cpp
@@ -48,7 +48,7 @@ void SimplifyMarkupCommand::doApply()
     // without affecting the style. The goal is to produce leaner markup even when starting
     // from a verbose fragment.
     // We look at inline elements as well as non top level divs that don't have attributes.
-    for (Node* node = m_firstNode.get(); node && node != m_nodeAfterLast; node = NodeTraversal::next(node)) {
+    for (Node* node = m_firstNode.get(); node && node != m_nodeAfterLast; node = NodeTraversal::next(*node)) {
         if (node->firstChild() || (node->isTextNode() && node->nextSibling()))
             continue;