Pass rootNode by reference when constructing node lists / collections

Source/core/dom/LiveNodeListBase.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 23 matching lines @@
 
 namespace WebCore {
 
 enum NodeListRootType {
     NodeListIsRootedAtNode,
     NodeListIsRootedAtDocument
 };
 
 class LiveNodeListBase {
 public:
-    LiveNodeListBase(ContainerNode* ownerNode, NodeListRootType rootType, NodeListInvalidationType invalidationType,
+    LiveNodeListBase(ContainerNode& ownerNode, NodeListRootType rootType, NodeListInvalidationType invalidationType,
         CollectionType collectionType)
         : m_ownerNode(ownerNode)
         , m_rootType(rootType)
         , m_invalidationType(invalidationType)
         , m_collectionType(collectionType)
     {
-        ASSERT(m_ownerNode);
         ASSERT(m_rootType == static_cast<unsigned>(rootType));
         ASSERT(m_invalidationType == static_cast<unsigned>(invalidationType));
         ASSERT(m_collectionType == static_cast<unsigned>(collectionType));
 
         document().registerNodeList(this);
     }
 
     virtual ~LiveNodeListBase()
     {
         document().unregisterNodeList(this);
@@ skipping 139 matching lines @@
     while ((next = nextMatchingElement(nodeList, *next, root))) {
         if (++currentOffset == offset)
             return next;
     }
     return 0;
 }
 
 } // namespace WebCore
 
 #endif // LiveNodeListBase_h