IntersectionObserver: use nullptr for implicit root.

third_party/WebKit/Source/core/dom/Document.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 118 matching lines @@
 class LayoutView;
 class LayoutViewItem;
 class LiveNodeListBase;
 class LocalDOMWindow;
 class Locale;
 class LocalFrame;
 class Location;
 class MediaQueryListListener;
 class MediaQueryMatcher;
 class NodeFilter;
-class NodeIntersectionObserverData;
 class NodeIterator;
 class NthIndexCache;
 class OriginAccessEntry;
 class Page;
 class PlatformMouseEvent;
 class ProcessingInstruction;
 class PropertyRegistry;
 class QualifiedName;
 class Range;
 class ResizeObserverController;
@@ skipping 656 matching lines @@
   bool hasMutationObserversOfType(MutationObserver::MutationType type) const {
     return m_mutationObserverTypes & type;
   }
   bool hasMutationObservers() const { return m_mutationObserverTypes; }
   void addMutationObserverTypes(MutationObserverOptions types) {
     m_mutationObserverTypes |= types;
   }
 
   IntersectionObserverController* intersectionObserverController();
   IntersectionObserverController& ensureIntersectionObserverController();
-  NodeIntersectionObserverData& ensureIntersectionObserverData();
 
   ResizeObserverController* resizeObserverController() const {
     return m_resizeObserverController;
   }
   ResizeObserverController& ensureResizeObserverController();
 
   void updateViewportDescription();
 
   // Returns the owning element in the parent document. Returns nullptr if
   // this is the top level document or the owner is remote.
@@ skipping 820 matching lines @@
 
   ParserSynchronizationPolicy m_parserSyncPolicy;
 
   HostsUsingFeatures::Value m_hostsUsingFeaturesValue;
 
   ClientHintsPreferences m_clientHintsPreferences;
 
   Member<CanvasFontCache> m_canvasFontCache;
 
   Member<IntersectionObserverController> m_intersectionObserverController;
-  Member<NodeIntersectionObserverData> m_intersectionObserverData;
   Member<ResizeObserverController> m_resizeObserverController;
 
   int m_nodeCount;
 
   bool m_mayContainV0Shadow = false;
 
   Member<SnapCoordinator> m_snapCoordinator;
 
   WouldLoadReason m_wouldLoadReason;
 
@@ skipping 49 matching lines @@
 DEFINE_TYPE_CASTS(TreeScope, Document, document, true, true);
 
 }  // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 CORE_EXPORT void showLiveDocumentInstances();
 #endif
 
 #endif  // Document_h