IntersectionObserver: notify when root or target is removed.

third_party/WebKit/Source/core/dom/IntersectionObservation.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef IntersectionObservation_h
 #define IntersectionObservation_h
 
 #include "core/dom/DOMHighResTimeStamp.h"
 #include "platform/geometry/LayoutRect.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class Element;
 class IntersectionObserver;
 
 class IntersectionObservation final : public GarbageCollected<IntersectionObservation> {
 public:
     IntersectionObservation(IntersectionObserver&, Element&, bool shouldReportRootBounds);
 
     struct IntersectionGeometry {
         LayoutRect targetRect;
         LayoutRect intersectionRect;
         LayoutRect rootRect;
         bool doesIntersect;
+
+        IntersectionGeometry() : doesIntersect(false) {}
     };
 
     IntersectionObserver& observer() const { return *m_observer; }
     Element* target() const { return m_target; }
     unsigned lastThresholdIndex() const { return m_lastThresholdIndex; }
     void setLastThresholdIndex(unsigned index) { m_lastThresholdIndex = index; }
     bool shouldReportRootBounds() const { return m_shouldReportRootBounds; }
     void computeIntersectionObservations(DOMHighResTimeStamp);
     void disconnect();
     void clearRootAndRemoveFromTarget();
@@ skipping 15 matching lines @@
 
     WeakMember<Element> m_target;
 
     unsigned m_shouldReportRootBounds : 1;
     unsigned m_lastThresholdIndex : 30;
 };
 
 } // namespace blink
 
 #endif // IntersectionObservation_h