Start autoplay muted videos with autoplay attribute when they are visible.

third_party/WebKit/Source/core/dom/IntersectionObserver.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 IntersectionObserver_h
 #define IntersectionObserver_h
 
+#include "bindings/core/v8/ExceptionStatePlaceholder.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/dom/IntersectionObservation.h"
 #include "core/dom/IntersectionObserverEntry.h"
 #include "platform/Length.h"
 #include "platform/heap/Handle.h"
 #include "wtf/HashSet.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
+class Document;
 class Element;
 class ExceptionState;
 class LayoutObject;
 class IntersectionObserverCallback;
 class IntersectionObserverInit;
 
 class CORE_EXPORT IntersectionObserver final : public GarbageCollectedFinalized<IntersectionObserver>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 
 public:
+    using EventCallback = Function<void(const HeapVector<Member<IntersectionObserverEntry>>&), WTF::SameThreadAffinity>;
+
     static IntersectionObserver* create(const IntersectionObserverInit&, IntersectionObserverCallback&, ExceptionState&);
+    static IntersectionObserver* create(const Vector<Length>& rootMargin, const Vector<float>& thresholds, Document*, std::unique_ptr<EventCallback>);
     static void resumeSuspendedObservers();
 
-    // API methods
-    void observe(Element*, ExceptionState&);
-    void unobserve(Element*, ExceptionState&);
+    // API methods.
+    void observe(Element*, ExceptionState& = ASSERT_NO_EXCEPTION);
+    void unobserve(Element*, ExceptionState& = ASSERT_NO_EXCEPTION);
     void disconnect(ExceptionState&);
     HeapVector<Member<IntersectionObserverEntry>> takeRecords(ExceptionState&);
 
-    // API attributes
+    // API attributes.
     Element* root() const;
     String rootMargin() const;
     const Vector<float>& thresholds() const { return m_thresholds; }
 
     Node* rootNode() const { return m_root.get(); }
     LayoutObject* rootLayoutObject() const;
     const Length& topMargin() const { return m_topMargin; }
     const Length& rightMargin() const { return m_rightMargin; }
     const Length& bottomMargin() const { return m_bottomMargin; }
     const Length& leftMargin() const { return m_leftMargin; }
@@ skipping 19 matching lines @@
     Vector<float> m_thresholds;
     Length m_topMargin;
     Length m_rightMargin;
     Length m_bottomMargin;
     Length m_leftMargin;
 };
 
 } // namespace blink
 
 #endif // IntersectionObserver_h