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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_BROWSER_MEDIA_MEDIA_POWER_EXPERIMENT_MANAGER_H_
#define CONTENT_BROWSER_MEDIA_MEDIA_POWER_EXPERIMENT_MANAGER_H_
#include <map>
#include <optional>
#include <set>
#include <vector>
#include "base/functional/callback.h"
#include "base/memory/scoped_refptr.h"
#include "base/sequence_checker.h"
#include "base/task/sequenced_task_runner.h"
#include "content/common/content_export.h"
#include "content/public/browser/media_player_id.h"
#include "media/base/video_codecs.h"
namespace content {
// Keeps track of all media players across all pages, and notifies them when
// they enter or leave an active experiment.
class CONTENT_EXPORT MediaPowerExperimentManager {
public:
// Callback to notify the client when an experiment starts / stops.
using ExperimentCB = base::RepeatingCallback<void(bool)>;
// Flags for handling notifications of stopped players.
enum class NotificationMode {
// If the stopped player is the current experiment, then notify it that it
// no longer is.
kNotify,
// If the stopped player is the current experiment, then skip notification.
// This is useful if the player is being destroyed.
kSkip
};
MediaPowerExperimentManager();
MediaPowerExperimentManager(const MediaPowerExperimentManager&) = delete;
MediaPowerExperimentManager& operator=(const MediaPowerExperimentManager&) =
delete;
virtual ~MediaPowerExperimentManager();
// May return nullptr if experiments aren't enabled.
static MediaPowerExperimentManager* Instance();
// Called when the given player begins playing. |cb| will be called if it
// becomes / stops being the only playing player, though never re-entrantly.
virtual void PlayerStarted(const MediaPlayerId& player, ExperimentCB cb);
// Called when the given player has stopped playing. It is okay if it was
// never started via PlayerStarted; we'll just ignore it. If
// |notification_mode| is kSkip, then we won't notify |player| that it's
// stopping, if it's the current experiment.
virtual void PlayerStopped(
const MediaPlayerId& player,
NotificationMode notification_mode = NotificationMode::kNotify);
private:
// Send start / stop notifications and update |current_experiment_player_|
// based on whether an experiment should be running.
void CheckExperimentState();
// Set of all playing players that we know about.
std::map<MediaPlayerId, ExperimentCB> players_;
// If set, this is the player that has a running experiment.
std::optional<MediaPlayerId> current_experiment_player_;
ExperimentCB current_experiment_cb_;
scoped_refptr<base::SequencedTaskRunner> task_runner_;
SEQUENCE_CHECKER(sequence_checker_);
};
} // namespace content
#endif // CONTENT_BROWSER_MEDIA_MEDIA_POWER_EXPERIMENT_MANAGER_H_
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