Update remaining NodeTraversal / ElementTraversal methods to take references

Source/core/rendering/CounterNode.h

Index: Source/core/rendering/CounterNode.h
diff --git a/Source/core/rendering/CounterNode.h b/Source/core/rendering/CounterNode.h
index c467036d0917f8737fbce092fb7e5323661091eb..baaeed3aa2934ab931880d2b33f1803b3c971707 100644
--- a/Source/core/rendering/CounterNode.h
+++ b/Source/core/rendering/CounterNode.h
@@ -42,13 +42,13 @@ class RenderCounter;
 
 class CounterNode : public RefCounted<CounterNode> {
 public:
-    static PassRefPtr<CounterNode> create(RenderObject*, bool isReset, int value);
+    static PassRefPtr<CounterNode> create(RenderObject&, bool isReset, int value);
     ~CounterNode();
     bool actsAsReset() const { return m_hasResetType || !m_parent; }
     bool hasResetType() const { return m_hasResetType; }
     int value() const { return m_value; }
     int countInParent() const { return m_countInParent; }
-    RenderObject* owner() const { return m_owner; }
+    RenderObject& owner() const { return m_owner; }
     void addRenderer(RenderCounter*);
     void removeRenderer(RenderCounter*);
 
@@ -71,7 +71,7 @@ public:
     void removeChild(CounterNode*);
 
 private:
-    CounterNode(RenderObject*, bool isReset, int value);
+    CounterNode(RenderObject&, bool isReset, int value);
     int computeCountInParent() const;
     // Invalidates the text in the renderer of this counter, if any,
     // and in the renderers of all descendants of this counter, if any.
@@ -81,7 +81,7 @@ private:
     bool m_hasResetType;
     int m_value;
     int m_countInParent;
-    RenderObject* m_owner;
+    RenderObject& m_owner;
     RenderCounter* m_rootRenderer;
 
     CounterNode* m_parent;