Pass rootNode by reference when constructing node lists / collections

Source/core/dom/ChildNodeList.h

Index: Source/core/dom/ChildNodeList.h
diff --git a/Source/core/dom/ChildNodeList.h b/Source/core/dom/ChildNodeList.h
index aab6861c3b2d1d309d1a8409e03dc818ede6de3d..c91a04354003b674386b9777669f070b09303a18 100644
--- a/Source/core/dom/ChildNodeList.h
+++ b/Source/core/dom/ChildNodeList.h
@@ -33,7 +33,7 @@ namespace WebCore {
 
 class ChildNodeList FINAL : public NodeList {
 public:
-    static PassRefPtr<ChildNodeList> create(PassRefPtr<ContainerNode> rootNode)
+    static PassRefPtr<ChildNodeList> create(ContainerNode& rootNode)
     {
         return adoptRef(new ChildNodeList(rootNode));
     }
@@ -56,7 +56,7 @@ public:
     Node* traverseForwardToOffset(unsigned offset, Node& currentNode, unsigned& currentOffset, const ContainerNode& root) const;
 
 private:
-    explicit ChildNodeList(PassRefPtr<ContainerNode> rootNode);
+    explicit ChildNodeList(ContainerNode& rootNode);
 
     virtual bool isChildNodeList() const OVERRIDE { return true; }
     virtual Node* virtualOwnerNode() const OVERRIDE;