Monitor the intersection of video and viewport.

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

Index: third_party/WebKit/Source/core/dom/IntersectionObserver.h
diff --git a/third_party/WebKit/Source/core/dom/IntersectionObserver.h b/third_party/WebKit/Source/core/dom/IntersectionObserver.h
index 3281fcea96352ef256fc00bd74383250e40b02ac..12c3104a091ee02eb8533279485fb10b5d87cb18 100644
--- a/third_party/WebKit/Source/core/dom/IntersectionObserver.h
+++ b/third_party/WebKit/Source/core/dom/IntersectionObserver.h
@@ -23,12 +23,14 @@ class LayoutObject;
 class IntersectionObserverCallback;
 class IntersectionObserverInit;
 
-class CORE_EXPORT IntersectionObserver final
+class CORE_EXPORT IntersectionObserver
     : public GarbageCollectedFinalized<IntersectionObserver>,
       public ScriptWrappable {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
+  virtual ~IntersectionObserver();
+
   using EventCallback =
       Function<void(const HeapVector<Member<IntersectionObserverEntry>>&),
                WTF::SameThreadAffinity>;
@@ -45,6 +47,7 @@ class CORE_EXPORT IntersectionObserver final
   static IntersectionObserver* create(const IntersectionObserverInit&,
                                       IntersectionObserverCallback&,
                                       ExceptionState&);
+  // Observes any changes on intersection rect when |thresholds| is empty.
   static IntersectionObserver* create(const Vector<Length>& rootMargin,
                                       const Vector<float>& thresholds,
                                       Document*,
@@ -89,11 +92,15 @@ class CORE_EXPORT IntersectionObserver final
 
   DECLARE_TRACE();
 
+ protected:
+  virtual IntersectionObservation* createObservation(Element&, bool);
+
+  IntersectionObserver(IntersectionObserverCallback&,
+                       Node&,
+                       const Vector<Length>& rootMargin,
+                       const Vector<float>& thresholds);
+
  private:
-  explicit IntersectionObserver(IntersectionObserverCallback&,
-                                Node&,
-                                const Vector<Length>& rootMargin,
-                                const Vector<float>& thresholds);
   void clearWeakMembers(Visitor*);
 
   Member<IntersectionObserverCallback> m_callback;
@@ -108,6 +115,19 @@ class CORE_EXPORT IntersectionObserver final
   InitialState m_initialState;
 };
 
+class ViewportIntersectionObserver final : public IntersectionObserver {
+  WTF_MAKE_NONCOPYABLE(ViewportIntersectionObserver);
+
+ public:
+  ViewportIntersectionObserver(IntersectionObserverCallback&,
+                               Node&,
+                               const Vector<Length>&);
+  ~ViewportIntersectionObserver() final;
+
+ protected:
+  IntersectionObservation* createObservation(Element&, bool) final;
+};
+
 }  // namespace blink
 
 #endif  // IntersectionObserver_h