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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "third_party/blink/renderer/platform/context_lifecycle_observer.h"
#include "third_party/blink/renderer/platform/context_lifecycle_notifier.h"
namespace blink {
ContextLifecycleObserver::~ContextLifecycleObserver() {
#if DCHECK_IS_ON()
// We want to make sure that if we are still waiting for a notification,
// then the context hasn't been GC'ed (or, in other words, if the WeakPtr is
// reset then `ContextDestroyed()` has been called).
// waiting_for_context_destroyed_ -> notifier_
// !waiting_for_context_destroyed_ || notifier_
DCHECK(!waiting_for_context_destroyed_ || notifier_);
#endif
}
void ContextLifecycleObserver::SetContextLifecycleNotifier(
ContextLifecycleNotifier* notifier) {
if (notifier == notifier_)
return;
if (notifier_)
notifier_->RemoveContextLifecycleObserver(this);
notifier_ = notifier;
#if DCHECK_IS_ON()
// If the notifier is not null we expect it to notify us when it is destroyed.
waiting_for_context_destroyed_ = !!notifier_;
#endif
if (notifier_)
notifier_->AddContextLifecycleObserver(this);
}
void ContextLifecycleObserver::NotifyContextDestroyed() {
#if DCHECK_IS_ON()
DCHECK(waiting_for_context_destroyed_);
waiting_for_context_destroyed_ = false;
#endif
ContextDestroyed();
notifier_ = nullptr;
}
void ContextLifecycleObserver::Trace(Visitor* visitor) const {
visitor->Trace(notifier_);
}
} // namespace blink
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