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// Copyright 2017 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 UI_BASE_SCOPED_VISIBILITY_TRACKER_H_
#define UI_BASE_SCOPED_VISIBILITY_TRACKER_H_
#include <memory>
#include "base/component_export.h"
#include "base/time/time.h"
namespace base {
class TickClock;
} // namespace base
namespace ui {
// This class tracks the total time it is visible, based on receiving
// OnShown/OnHidden notifications, which are logically idempotent.
class COMPONENT_EXPORT(UI_BASE) ScopedVisibilityTracker {
public:
// |tick_clock| must outlive this object.
ScopedVisibilityTracker(const base::TickClock* tick_clock, bool is_shown);
~ScopedVisibilityTracker();
void OnShown();
void OnHidden();
base::TimeDelta GetForegroundDuration() const;
bool currently_in_foreground() const { return currently_in_foreground_; }
private:
void Update(bool in_foreground);
const base::TickClock* tick_clock_;
base::TimeTicks last_time_shown_;
base::TimeDelta foreground_duration_;
bool currently_in_foreground_ = false;
};
} // namespace ui
#endif // UI_BASE_SCOPED_VISIBILITY_TRACKER_H_
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