Implement suspend/resume for IntersectionObserver notifications.

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 b0a7d6840732c2405363ac2f822c1367ee20aece..7b68c8dd8cf13d314a80354bda77fd244b747848 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -5069,10 +5069,15 @@ WeakPtrWillBeRawPtr<Document> Document::createWeakPtr()
 #endif
 }
 
+IntersectionObserverController* Document::intersectionObserverController()
+{
+    return m_intersectionObserverController;
+}
+
 IntersectionObserverController& Document::ensureIntersectionObserverController()
 {
     if (!m_intersectionObserverController)
-        m_intersectionObserverController = new IntersectionObserverController();
+        m_intersectionObserverController = IntersectionObserverController::create(this);
     return *m_intersectionObserverController;
 }