Fixit: Move tab and desktop capture code to new location.

content/browser/renderer_host/media/video_capture_oracle.h

-// Copyright (c) 2013 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 CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_ORACLE_H_
-#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_ORACLE_H_
-
-#include "base/callback_forward.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/time/time.h"
-#include "content/common/content_export.h"
-
-namespace content {
-
-// Filters a sequence of events to achieve a target frequency.
-class CONTENT_EXPORT SmoothEventSampler {
- public:
-  explicit SmoothEventSampler(base::TimeDelta capture_period,
-                              bool events_are_reliable,
-                              int redundant_capture_goal);
-
-  // Add a new event to the event history, and return whether it ought to be
-  // sampled based on the desired |capture_period|. The event is not recorded as
-  // a sample until RecordSample() is called.
-  bool AddEventAndConsiderSampling(base::TimeTicks event_time);
-
-  // Operates on the last event added by AddEventAndConsiderSampling(), 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, at time |event_time|, sampling should occur because too
-  // much time will have passed relative to the last event and/or sample.
-  bool IsOverdueForSamplingAt(base::TimeTicks event_time) const;
-
-  // Returns true if AddEventAndConsiderSampling() has been called since the
-  // last call to RecordSample().
-  bool HasUnrecordedEvent() const;
-
- private:
-  const bool events_are_reliable_;
-  const base::TimeDelta capture_period_;
-  const int redundant_capture_goal_;
-  const base::TimeDelta token_bucket_capacity_;
-
-  base::TimeTicks current_event_;
-  base::TimeTicks last_sample_;
-  int overdue_sample_count_;
-  base::TimeDelta token_bucket_;
-
-  DISALLOW_COPY_AND_ASSIGN(SmoothEventSampler);
-};
-
-// VideoCaptureOracle manages the producer-side throttling of captured frames
-// from a video capture device.  It is informed of every update by the device;
-// this empowers it to look into the future and decide if a particular frame
-// ought to be captured in order to achieve its target frame rate.
-class CONTENT_EXPORT VideoCaptureOracle {
- public:
-  enum Event {
-    kTimerPoll,
-    kCompositorUpdate,
-    kSoftwarePaint,
-  };
-
-  VideoCaptureOracle(base::TimeDelta capture_period,
-                     bool events_are_reliable);
-  virtual ~VideoCaptureOracle() {}
-
-  // Record an event of type |event|, and decide whether the caller should do a
-  // frame capture immediately. Decisions of the oracle are final: the caller
-  // must do what it is told.
-  bool ObserveEventAndDecideCapture(Event event, base::TimeTicks event_time);
-
-  // Record the start of a capture.  Returns a frame_number to be used with
-  // CompleteCapture().
-  int RecordCapture();
-
-  // Record the completion of a capture.  Returns true iff the captured frame
-  // should be delivered.
-  bool CompleteCapture(int frame_number, base::TimeTicks timestamp);
-
-  base::TimeDelta capture_period() const { return capture_period_; }
-
- private:
-
-  // Time between frames.
-  const base::TimeDelta capture_period_;
-
-  // Incremented every time a paint or update event occurs.
-  int frame_number_;
-
-  // Stores the frame number from the last delivered frame.
-  int last_delivered_frame_number_;
-
-  // Stores the timestamp of the last delivered frame.
-  base::TimeTicks last_delivered_frame_timestamp_;
-
-  // Tracks present/paint history.
-  SmoothEventSampler sampler_;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_ORACLE_H_