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// 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 CHROME_BROWSER_METRICS_DESKTOP_SESSION_DURATION_DESKTOP_SESSION_DURATION_TRACKER_H_
#define CHROME_BROWSER_METRICS_DESKTOP_SESSION_DURATION_DESKTOP_SESSION_DURATION_TRACKER_H_
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "chrome/browser/metrics/desktop_session_duration/audible_contents_tracker.h"
#include "chrome/browser/metrics/desktop_session_duration/chrome_visibility_observer.h"
namespace metrics {
// Class for tracking and recording session length on desktop based on browser
// visibility, audio and user interaction.
class DesktopSessionDurationTracker : public AudibleContentsTracker::Observer {
public:
// The methods for the observer will be called on the UI thread.
class Observer {
public:
virtual ~Observer() {}
virtual void OnSessionStarted(base::TimeTicks session_start) {}
virtual void OnSessionEnded(base::TimeDelta session_length) {}
};
// Creates the |DesktopSessionDurationTracker| instance and initializes the
// observers that notify to it.
static void Initialize();
// Returns true if the |DesktopSessionDurationTracker| instance has been
// created.
static bool IsInitialized();
// Returns the |DesktopSessionDurationTracker| instance.
static DesktopSessionDurationTracker* Get();
// Called when user interaction with the browser is caught.
void OnUserEvent();
// Called when visibility of the browser changes. These events can be delayed
// due to timeout logic, the extent of which can be communicated via
// |time_ago|. This time is used to correct the session duration.
void OnVisibilityChanged(bool visible, base::TimeDelta time_ago);
bool is_visible() const { return is_visible_; }
bool in_session() const { return in_session_; }
bool is_audio_playing() const { return is_audio_playing_; }
void SetInactivityTimeoutForTesting(base::TimeDelta inactivity_timeout) {
inactivity_timeout_ = inactivity_timeout;
}
// For observing the status of the session tracker.
void AddObserver(Observer* observer);
void RemoveObserver(Observer* observer);
// Cleans up any global state for testing.
static void CleanupForTesting();
protected:
DesktopSessionDurationTracker();
~DesktopSessionDurationTracker() override;
// AudibleContentsTracker::Observer
void OnAudioStart() override;
void OnAudioEnd() override;
// Decides whether session should be ended. Called when timer for inactivity
// timeout was fired. Overridden by tests.
virtual void OnTimerFired();
private:
// Starts timer based on |inactivity_timeout_|.
void StartTimer(base::TimeDelta duration);
// Marks the start of the session.
void StartSession();
// Ends the session and saves session information into histograms.
// |time_to_discount| contains the amount of time that should be removed from
// the apparent session length due to timeout logic.
void EndSession(base::TimeDelta time_to_discount);
// Sets |inactivity_timeout_| based on variation params.
void InitInactivityTimeout();
// Used for marking start if the session.
base::TimeTicks session_start_;
// Used for marking last user interaction.
base::TimeTicks last_user_event_;
// Used for marking current state of the user engagement.
bool is_visible_ = false;
bool in_session_ = false;
bool is_audio_playing_ = false;
bool is_first_session_ = true;
// Timeout for waiting for user interaction.
base::TimeDelta inactivity_timeout_;
base::OneShotTimer timer_;
base::ObserverList<Observer>::Unchecked observer_list_;
ChromeVisibilityObserver visibility_observer_;
AudibleContentsTracker audio_tracker_;
base::WeakPtrFactory<DesktopSessionDurationTracker> weak_factory_;
DISALLOW_COPY_AND_ASSIGN(DesktopSessionDurationTracker);
};
} // namespace metrics
#endif // CHROME_BROWSER_METRICS_DESKTOP_SESSION_DURATION_DESKTOP_SESSION_DURATION_TRACKER_H_