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// Copyright 2014 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 MEDIA_BASE_WALL_CLOCK_TIME_SOURCE_H_
#define MEDIA_BASE_WALL_CLOCK_TIME_SOURCE_H_
#include "base/memory/scoped_ptr.h"
#include "media/base/media_export.h"
#include "media/base/time_source.h"
namespace base {
class TickClock;
}
namespace media {
// A time source that uses interpolation based on the system clock.
class MEDIA_EXPORT WallClockTimeSource : public TimeSource {
public:
WallClockTimeSource();
virtual ~WallClockTimeSource();
// TimeSource implementation.
virtual void StartTicking() OVERRIDE;
virtual void StopTicking() OVERRIDE;
virtual void SetPlaybackRate(float playback_rate) OVERRIDE;
virtual void SetMediaTime(base::TimeDelta time) OVERRIDE;
virtual base::TimeDelta CurrentMediaTime() OVERRIDE;
void SetTickClockForTesting(scoped_ptr<base::TickClock> tick_clock);
private:
scoped_ptr<base::TickClock> tick_clock_;
bool ticking_;
// While ticking we can interpolate the current media time by measuring the
// delta between our reference ticks and the current system ticks and scaling
// that time by the playback rate.
float playback_rate_;
base::TimeDelta base_time_;
base::TimeTicks reference_wall_ticks_;
DISALLOW_COPY_AND_ASSIGN(WallClockTimeSource);
};
} // namespace media
#endif // MEDIA_BASE_WALL_CLOCK_TIME_SOURCE_H_
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