IntersectionObserver: second cut.

third_party/WebKit/Source/core/dom/IntersectionObserverCallback.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 IntersectionObserverCallback_h
+#define IntersectionObserverCallback_h
+
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class ExecutionContext;
+class IntersectionObserver;
+class IntersectionObserverEntry;
+
+class IntersectionObserverCallback : public GarbageCollectedFinalized<IntersectionObserverCallback> {
+public:
+    virtual void handleEvent(const HeapVector<Member<IntersectionObserverEntry>>&, IntersectionObserver&) = 0;
+    virtual ExecutionContext* executionContext() const = 0;
+    DEFINE_INLINE_VIRTUAL_TRACE() { }
+};
+
+}
+
+#endif // IntersectionObserverCallback_h