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

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

 /*
  * 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, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 65 matching lines @@
 #include "core/dom/ExecutionContextTask.h"
 #include "core/dom/FrameRequestCallback.h"
 #include "core/dom/IntersectionObserverController.h"
 #include "core/dom/LayoutTreeBuilderTraversal.h"
 #include "core/dom/MainThreadTaskRunner.h"
 #include "core/dom/Microtask.h"
 #include "core/dom/MutationObserver.h"
 #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"
 #include "core/dom/NodeWithIndex.h"
 #include "core/dom/NthIndexCache.h"
 #include "core/dom/ProcessingInstruction.h"
 #include "core/dom/ScriptRunner.h"
 #include "core/dom/ScriptedAnimationController.h"
 #include "core/dom/ScriptedIdleTaskController.h"
 #include "core/dom/SelectorQuery.h"
@@ skipping 506 matching lines @@
     // FIXME: consider using ActiveDOMObject.
     if (m_scriptedAnimationController)
         m_scriptedAnimationController->clearDocumentPointer();
     m_scriptedAnimationController.clear();
 
     m_scriptedIdleTaskController.clear();
 
     if (svgExtensions())
         accessSVGExtensions().pauseAnimations();
 
+    if (m_intersectionObserverData)
+        m_intersectionObserverData->dispose();
+
     m_lifecycle.advanceTo(DocumentLifecycle::Disposed);
     DocumentLifecycleNotifier::notifyDocumentWasDisposed();
 
     m_canvasFontCache.clear();
 }
 #endif
 
 SelectorQueryCache& Document::selectorQueryCache()
 {
     if (!m_selectorQueryCache)
@@ skipping 4452 matching lines @@
     return m_intersectionObserverController;
 }
 
 IntersectionObserverController& Document::ensureIntersectionObserverController()
 {
     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)
 {
     InspectorInstrumentation::scriptExecutionBlockedByCSP(this, directiveText);
 }
 
 void Document::addConsoleMessage(PassRefPtrWillBeRawPtr<ConsoleMessage> consoleMessage)
 {
     if (!isContextThread()) {
         m_taskRunner->postTask(BLINK_FROM_HERE, AddConsoleMessageTask::create(consoleMessage->source(), consoleMessage->level(), consoleMessage->message()));
         return;
@@ skipping 807 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     Document::WeakDocumentSet& set = Document::liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().string().utf8().data());
 }
 #endif