[Background Sync] Converting Blink code to the MVP API

Source/modules/background_sync/PeriodicSyncEvent.cpp

+// 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.
+
+#include "config.h"
+#include "modules/background_sync/PeriodicSyncEvent.h"
+
+namespace blink {
+
+PeriodicSyncEvent::PeriodicSyncEvent()
+{
+}
+
+PeriodicSyncEvent::PeriodicSyncEvent(const AtomicString& type, PeriodicSyncRegistration* syncRegistration, WaitUntilObserver* observer)
+    : ExtendableEvent(type, ExtendableEventInit(), observer)
+    , m_syncRegistration(syncRegistration)
+{
+}
+
+PeriodicSyncEvent::PeriodicSyncEvent(const AtomicString& type, const PeriodicSyncEventInit& init)
+    : ExtendableEvent(type, init)
+{
+    m_syncRegistration = init.registration();
+}
+
+PeriodicSyncEvent::~PeriodicSyncEvent()
+{
+}
+
+const AtomicString& PeriodicSyncEvent::interfaceName() const
+{
+    return EventNames::PeriodicSyncEvent;
+}
+
+PeriodicSyncRegistration* PeriodicSyncEvent::registration()
+{
+    return m_syncRegistration.get();
+}
+
+DEFINE_TRACE(PeriodicSyncEvent)
+{
+    visitor->trace(m_syncRegistration);
+    ExtendableEvent::trace(visitor);
+}
+
+} // namespace blink