Introduce few const getters for dom classes

third_party/WebKit/Source/core/dom/Node.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) 2004-2011, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 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
  * License as published by the Free Software Foundation; either
@@ skipping 637 matching lines @@
     DispatchEventResult dispatchMouseEvent(const PlatformMouseEvent&, const AtomicString& eventType, int clickCount = 0, Node* relatedTarget = nullptr);
 
     void dispatchSimulatedClick(Event* underlyingEvent, SimulatedClickMouseEventOptions = SendNoEvents, SimulatedClickCreationScope = SimulatedClickCreationScope::FromUserAgent);
 
     void dispatchInputEvent();
 
     // Perform the default action for an event.
     virtual void defaultEventHandler(Event*);
     virtual void willCallDefaultEventHandler(const Event&);
 
-    EventTargetData* eventTargetData() override;
+    EventTargetData* eventTargetData() const override;
     EventTargetData& ensureEventTargetData() override;
 
     void getRegisteredMutationObserversOfType(HeapHashMap<Member<MutationObserver>, MutationRecordDeliveryOptions>&, MutationObserver::MutationType, const QualifiedName* attributeName);
     void registerMutationObserver(MutationObserver&, MutationObserverOptions, const HashSet<AtomicString>& attributeFilter);
     void unregisterMutationObserver(MutationObserverRegistration*);
     void registerTransientMutationObserver(MutationObserverRegistration*);
     void unregisterTransientMutationObserver(MutationObserverRegistration*);
     void notifyMutationObserversNodeWillDetach();
 
     unsigned connectedSubframeCount() const;
@@ skipping 97 matching lines @@
 
     static void reattachWhitespaceSiblingsIfNeeded(Text* start);
 
 #if !ENABLE(OILPAN)
     void willBeDeletedFromDocument();
 #endif
 
     bool hasRareData() const { return getFlag(HasRareDataFlag); }
 
     NodeRareData* rareData() const;
+    NodeRareData* maybeRareData() const;
     NodeRareData& ensureRareData();
 #if !ENABLE(OILPAN)
     void clearRareData();
 
     void clearEventTargetData();
 #endif
 
     void setHasCustomStyleCallbacks() { setFlag(true, HasCustomStyleCallbacksFlag); }
 
     void setTreeScope(TreeScope* scope) { m_treeScope = scope; }
@@ skipping 141 matching lines @@
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showNode(const blink::Node*);
 void showTree(const blink::Node*);
 void showNodePath(const blink::Node*);
 #endif
 
 #endif // Node_h