Presentation API: implement .getAvalability() (Blink side).

Source/modules/presentation/AvailableChangeEvent.h

-// Copyright 2015 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 AvailableChangeEvent_h
-#define AvailableChangeEvent_h
-
-#include "modules/EventModules.h"
-#include "modules/presentation/AvailableChangeEventInit.h"
-#include "platform/heap/Handle.h"
-
-namespace blink {
-
-// AvailableChangeEvent object definition corresponding to the event IDL from the Presentation API,
-// see https://w3c.github.io/presentation-api/#availablechangeevent for details.
-class AvailableChangeEvent final : public Event {
-    DEFINE_WRAPPERTYPEINFO();
-public:
-    virtual ~AvailableChangeEvent();
-
-    static PassRefPtrWillBeRawPtr<AvailableChangeEvent> create()
-    {
-        return adoptRefWillBeNoop(new AvailableChangeEvent);
-    }
-    static PassRefPtrWillBeRawPtr<AvailableChangeEvent> create(const AtomicString& eventType, bool available)
-    {
-        return adoptRefWillBeNoop(new AvailableChangeEvent(eventType, available));
-    }
-    static PassRefPtrWillBeRawPtr<AvailableChangeEvent> create(const AtomicString& eventType, const AvailableChangeEventInit& initializer)
-    {
-        return adoptRefWillBeNoop(new AvailableChangeEvent(eventType, initializer));
-    }
-
-    bool available() const { return m_available; }
-
-    virtual const AtomicString& interfaceName() const override;
-
-private:
-    AvailableChangeEvent();
-    AvailableChangeEvent(const AtomicString& eventType, bool available);
-    AvailableChangeEvent(const AtomicString& eventType, const AvailableChangeEventInit& initializer);
-
-    bool m_available;
-};
-
-DEFINE_TYPE_CASTS(AvailableChangeEvent, Event, event, event->interfaceName() == EventNames::AvailableChangeEvent, event.interfaceName() == EventNames::AvailableChangeEvent);
-
-} // namespace blink
-
-#endif // AvailableChangeEvent_h