Revert of Use Document, rather than document element, for implicit root.

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

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 1b49e4059790cb0f91029de98ece39b33db2addb..7b68c8dd8cf13d314a80354bda77fd244b747848 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -83,7 +83,6 @@
 #include "core/dom/NodeChildRemovalTracker.h"
 #include "core/dom/NodeComputedStyle.h"
 #include "core/dom/NodeFilter.h"
-#include "core/dom/NodeIntersectionObserverData.h"
 #include "core/dom/NodeIterator.h"
 #include "core/dom/NodeRareData.h"
 #include "core/dom/NodeTraversal.h"
@@ -610,9 +609,6 @@
     if (svgExtensions())
         accessSVGExtensions().pauseAnimations();
 
-    if (m_intersectionObserverData)
-        m_intersectionObserverData->dispose();
-
     m_lifecycle.advanceTo(DocumentLifecycle::Disposed);
     DocumentLifecycleNotifier::notifyDocumentWasDisposed();
 
@@ -5083,13 +5079,6 @@
     if (!m_intersectionObserverController)
         m_intersectionObserverController = IntersectionObserverController::create(this);
     return *m_intersectionObserverController;
-}
-
-NodeIntersectionObserverData& Document::ensureIntersectionObserverData()
-{
-    if (!m_intersectionObserverData)
-        m_intersectionObserverData = new NodeIntersectionObserverData();
-    return *m_intersectionObserverData;
 }
 
 void Document::reportBlockedScriptExecutionToInspector(const String& directiveText)