IntersectionObserver: second cut.

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 fa6942c7490bd60df74c479be7a2c5e3461f56e0..ea83338acbc12f6b27c4091b36e3fb434051d788 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -76,6 +76,7 @@
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContextTask.h"
 #include "core/dom/FrameRequestCallback.h"
+#include "core/dom/IntersectionObservationRegistry.h"
 #include "core/dom/LayoutTreeBuilderTraversal.h"
 #include "core/dom/MainThreadTaskRunner.h"
 #include "core/dom/Microtask.h"
@@ -432,6 +433,7 @@ Document::Document(const DocumentInit& initializer, DocumentClassFlags documentC
     , m_loadEventDelayCount(0)
     , m_loadEventDelayTimer(this, &Document::loadEventDelayTimerFired)
     , m_pluginLoadingTimer(this, &Document::pluginLoadingTimerFired)
+    , m_deliverIntersectionObservationsTimer(this, &Document::deliverIntersectionObservationsTimerFired)
     , m_documentTiming(*this)
     , m_writeRecursionIsTooDeep(false)
     , m_writeRecursionDepth(0)
@@ -602,6 +604,8 @@ void Document::dispose()
     if (svgExtensions())
         accessSVGExtensions().pauseAnimations();
 
+    m_deliverIntersectionObservationsTimer.stop();
+
     m_lifecycle.advanceTo(DocumentLifecycle::Disposed);
     DocumentLifecycleNotifier::notifyDocumentWasDisposed();
 
@@ -4966,6 +4970,27 @@ void Document::parseDNSPrefetchControlHeader(const String& dnsPrefetchControl)
     m_haveExplicitlyDisabledDNSPrefetch = true;
 }
 
+WeakPtr<Document> Document::createWeakPtr()
+{
+    if (!m_weakPointerFactory)
+        m_weakPointerFactory = adoptPtrWillBeNoop(new WeakPtrFactory<Document>(this));
+    return m_weakPointerFactory->createWeakPtr();
+}
+
+IntersectionObservationRegistry* Document::intersectionObservationRegistry()
+{
+    if (!m_intersectionObservationRegistry)
+        m_intersectionObservationRegistry = adoptPtrWillBeNoop(new IntersectionObservationRegistry(m_deliverIntersectionObservationsTimer));
+    return m_intersectionObservationRegistry.get();
+}
+
+void Document::deliverIntersectionObservationsTimerFired(Timer<Document>*)
+{
+    ASSERT(isMainThread());
+    ASSERT(m_intersectionObservationRegistry);
+    m_intersectionObservationRegistry->deliverIntersectionObservations();
+}
+
 void Document::reportBlockedScriptExecutionToInspector(const String& directiveText)
 {
     InspectorInstrumentation::scriptExecutionBlockedByCSP(this, directiveText);
@@ -5023,6 +5048,8 @@ void Document::tasksWereResumed()
         m_scriptedAnimationController->resume();
 
     MutationObserver::resumeSuspendedObservers();
+    if (m_intersectionObservationRegistry)
+        m_intersectionObservationRegistry->resumeSuspendedIntersectionObservers();
     if (m_domWindow)
         DOMWindowPerformance::performance(*m_domWindow)->resumeSuspendedObservers();
 }
@@ -5806,6 +5833,7 @@ DEFINE_TRACE(Document)
     visitor->trace(m_compositorPendingAnimations);
     visitor->trace(m_contextDocument);
     visitor->trace(m_canvasFontCache);
+    visitor->trace(m_intersectionObservationRegistry);
     WillBeHeapSupplementable<Document>::trace(visitor);
 #endif
     TreeScope::trace(visitor);