Monitor the intersection of video and viewport.

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> {
+class IntersectionObservation
+    : public GarbageCollectedFinalized<IntersectionObservation> {
+  WTF_MAKE_NONCOPYABLE(IntersectionObservation);
+
  public:
   IntersectionObservation(IntersectionObserver&,
                           Element&,
                           bool shouldReportRootBounds);
+  virtual ~IntersectionObservation();
 
   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);
+  virtual void computeIntersectionObservations(DOMHighResTimeStamp);
   void disconnect();
   void clearRootAndRemoveFromTarget();
 
   DECLARE_TRACE();
 
+ protected:
+  bool computeGeometry(IntersectionGeometry&) const;
+
  private:
   void applyRootMargin(LayoutRect&) const;
   void initializeGeometry(IntersectionGeometry&) const;
   void initializeTargetRect(LayoutRect&) const;
   void initializeRootRect(LayoutRect&) const;
   void clipToRoot(IntersectionGeometry&) const;
   void mapTargetRectToTargetFrameCoordinates(LayoutRect&) const;
   void mapRootRectToRootFrameCoordinates(LayoutRect&) const;
   void mapRootRectToTargetFrameCoordinates(LayoutRect&) const;
-  bool computeGeometry(IntersectionGeometry&) const;
 
   Member<IntersectionObserver> m_observer;
 
   WeakMember<Element> m_target;
 
   unsigned m_shouldReportRootBounds : 1;
   unsigned m_lastThresholdIndex : 30;
 };
 
+class ViewportIntersectionObservation final : public IntersectionObservation {
+  WTF_MAKE_NONCOPYABLE(ViewportIntersectionObservation);
+
+ public:
+  ViewportIntersectionObservation(IntersectionObserver&, Element&);
+  ~ViewportIntersectionObservation() final;
+
+  void computeIntersectionObservations(DOMHighResTimeStamp) final;
+
+ private:
+  LayoutRect m_lastIntersectRect;
+};
+
 }  // namespace blink
 
 #endif  // IntersectionObservation_h