[WIP] Move media/capture to device/capture

media/capture/content/smooth_event_sampler.h

-// Copyright (c) 2015 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_CAPTURE_CONTENT_SMOOTH_EVENT_SAMPLER_H_
-#define MEDIA_CAPTURE_CONTENT_SMOOTH_EVENT_SAMPLER_H_
-
-#include "base/macros.h"
-#include "base/time/time.h"
-#include "media/capture/capture_export.h"
-
-namespace media {
-
-// Filters a sequence of events to achieve a target frequency.
-class CAPTURE_EXPORT SmoothEventSampler {
- public:
-  explicit SmoothEventSampler(base::TimeDelta min_capture_period);
-
-  // Get/Set minimum capture period. When setting a new value, the state of the
-  // sampler is retained so that sampling will continue smoothly.
-  base::TimeDelta min_capture_period() const { return min_capture_period_; }
-  void SetMinCapturePeriod(base::TimeDelta p);
-
-  // Add a new event to the event history, and consider whether it ought to be
-  // sampled. The event is not recorded as a sample until RecordSample() is
-  // called.
-  void ConsiderPresentationEvent(base::TimeTicks event_time);
-
-  // Returns true if the last event considered should be sampled.
-  bool ShouldSample() const;
-
-  // Operates on the last event added by ConsiderPresentationEvent(), marking
-  // it as sampled. After this point we are current in the stream of events, as
-  // we have sampled the most recent event.
-  void RecordSample();
-
-  // Returns true if ConsiderPresentationEvent() has been called since the last
-  // call to RecordSample().
-  bool HasUnrecordedEvent() const;
-
- private:
-  base::TimeDelta min_capture_period_;
-  base::TimeDelta token_bucket_capacity_;
-
-  base::TimeTicks current_event_;
-  base::TimeTicks last_sample_;
-  base::TimeDelta token_bucket_;
-
-  DISALLOW_COPY_AND_ASSIGN(SmoothEventSampler);
-};
-
-}  // namespace media
-
-#endif  // MEDIA_CAPTURE_CONTENT_SMOOTH_EVENT_SAMPLER_H_