IntersectionObserver: use nullptr for implicit root.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc.
  * All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
@@ skipping 39 matching lines @@
 #include "core/css/resolver/StyleResolver.h"
 #include "core/css/resolver/StyleResolverStats.h"
 #include "core/css/resolver/StyleSharingDepthScope.h"
 #include "core/dom/AXObjectCache.h"
 #include "core/dom/Attr.h"
 #include "core/dom/CSSSelectorWatch.h"
 #include "core/dom/ClientRect.h"
 #include "core/dom/ClientRectList.h"
 #include "core/dom/DatasetDOMStringMap.h"
 #include "core/dom/ElementDataCache.h"
+#include "core/dom/ElementIntersectionObserverData.h"
 #include "core/dom/ElementRareData.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/FirstLetterPseudoElement.h"
 #include "core/dom/Fullscreen.h"
 #include "core/dom/LayoutTreeBuilder.h"
 #include "core/dom/MutationObserverInterestGroup.h"
 #include "core/dom/MutationRecord.h"
 #include "core/dom/NamedNodeMap.h"
 #include "core/dom/NodeComputedStyle.h"
-#include "core/dom/NodeIntersectionObserverData.h"
 #include "core/dom/PresentationAttributeStyle.h"
 #include "core/dom/PseudoElement.h"
 #include "core/dom/ScriptableDocumentParser.h"
 #include "core/dom/SelectorQuery.h"
 #include "core/dom/StyleChangeReason.h"
 #include "core/dom/StyleEngine.h"
 #include "core/dom/Text.h"
 #include "core/dom/custom/CustomElement.h"
 #include "core/dom/custom/CustomElementRegistry.h"
 #include "core/dom/custom/V0CustomElement.h"
@@ skipping 2788 matching lines @@
     return nullptr;
   }
 
   exceptionState.throwDOMException(
       SyntaxError, "The value provided ('" + where +
                        "') is not one of 'beforeBegin', 'afterBegin', "
                        "'beforeEnd', or 'afterEnd'.");
   return nullptr;
 }
 
-NodeIntersectionObserverData* Element::intersectionObserverData() const {
+ElementIntersectionObserverData* Element::intersectionObserverData() const {
   if (hasRareData())
     return elementRareData()->intersectionObserverData();
   return nullptr;
 }
 
-NodeIntersectionObserverData& Element::ensureIntersectionObserverData() {
+ElementIntersectionObserverData& Element::ensureIntersectionObserverData() {
   return ensureElementRareData().ensureIntersectionObserverData();
 }
 
 HeapHashMap<Member<ResizeObserver>, Member<ResizeObservation>>*
 Element::resizeObserverData() const {
   if (hasRareData())
     return elementRareData()->resizeObserverData();
   return nullptr;
 }
 
@@ skipping 1195 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(Element) {
   if (hasRareData()) {
     visitor->traceWrappers(elementRareData());
   }
   ContainerNode::traceWrappers(visitor);
 }
 
 }  // namespace blink