Introduce few const getters for dom classes

third_party/WebKit/Source/core/dom/Node.cpp

 /*
  * 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, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 321 matching lines @@
     document.markers().removeMarkers(this);
 }
 #endif
 
 NodeRareData* Node::rareData() const
 {
     ASSERT_WITH_SECURITY_IMPLICATION(hasRareData());
     return static_cast<NodeRareData*>(m_data.m_rareData);
 }
 
+NodeRareData* Node::maybeRareData() const
+{
+    return hasRareData() ? rareData() : nullptr;
+}
+
 NodeRareData& Node::ensureRareData()
 {
     if (hasRareData())
         return *rareData();
 
     if (isElementNode())
         m_data.m_rareData = ElementRareData::create(m_data.m_layoutObject);
     else
         m_data.m_rareData = NodeRareData::create(m_data.m_layoutObject);
 
@@ skipping 1533 matching lines @@
 void Node::removeAllEventListenersRecursively()
 {
     ScriptForbiddenScope forbidScriptDuringRawIteration;
     for (Node& node : NodeTraversal::startsAt(this)) {
         node.removeAllEventListeners();
         for (ShadowRoot* root = node.youngestShadowRoot(); root; root = root->olderShadowRoot())
             root->removeAllEventListenersRecursively();
     }
 }
 
-using EventTargetDataMap = HeapHashMap<WeakMember<Node>, Member<EventTargetData>>;
+using EventTargetDataMap = HeapHashMap<WeakMember<const Node>, Member<EventTargetData>>;
 static EventTargetDataMap& eventTargetDataMap()
 {
     DEFINE_STATIC_LOCAL(EventTargetDataMap, map, (new EventTargetDataMap));
     return map;
 }
 
-EventTargetData* Node::eventTargetData()
+EventTargetData* Node::eventTargetData() const
 {
     return hasEventTargetData() ? eventTargetDataMap().get(this) : nullptr;
 }
 
 EventTargetData& Node::ensureEventTargetData()
 {
     if (hasEventTargetData())
         return *eventTargetDataMap().get(this);
     DCHECK(!eventTargetDataMap().contains(this));
     setHasEventTargetData(true);
@@ skipping 540 matching lines @@
 
 void showNodePath(const blink::Node* node)
 {
     if (node)
         node->showNodePathForThis();
     else
         fprintf(stderr, "Cannot showNodePath for (nil)\n");
 }
 
 #endif