Clean-up: Break sampler classes into their own files.

content/browser/media/capture/video_capture_oracle.h

Index: content/browser/media/capture/video_capture_oracle.h
diff --git a/content/browser/media/capture/video_capture_oracle.h b/content/browser/media/capture/video_capture_oracle.h
index db98b49e571dfe89b0d6d614204aaea9127d47d4..706f4a92dc537cf2a3d0bd2f45484e304d9427e5 100644
--- a/content/browser/media/capture/video_capture_oracle.h
+++ b/content/browser/media/capture/video_capture_oracle.h
@@ -5,167 +5,16 @@
 #ifndef CONTENT_BROWSER_MEDIA_CAPTURE_VIDEO_CAPTURE_ORACLE_H_
 #define CONTENT_BROWSER_MEDIA_CAPTURE_VIDEO_CAPTURE_ORACLE_H_
 
-#include <deque>
-
 #include "base/callback_forward.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
+#include "content/browser/media/capture/animated_content_sampler.h"
+#include "content/browser/media/capture/smooth_event_sampler.h"
 #include "content/common/content_export.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace content {
 
-// Filters a sequence of events to achieve a target frequency.
-class CONTENT_EXPORT SmoothEventSampler {
- public:
-  SmoothEventSampler(base::TimeDelta min_capture_period,
-                     int redundant_capture_goal);
-
-  base::TimeDelta min_capture_period() const { return min_capture_period_; }
-
-  // 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, 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 ConsiderPresentationEvent() has been called since the last
-  // call to RecordSample().
-  bool HasUnrecordedEvent() const;
-
- private:
-  const base::TimeDelta min_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);
-};
-
-// Analyzes a sequence of events to detect the presence of constant frame rate
-// animated content.  In the case where there are multiple regions of animated
-// content, AnimatedContentSampler will propose sampling the one having the
-// largest "smoothness" impact, according to human perception (e.g., a 24 FPS
-// video versus a 60 FPS busy spinner).
-//
-// In addition, AnimatedContentSampler will provide rewritten frame timestamps,
-// for downstream consumers, that are "truer" to the source content than to the
-// local presentation hardware.
-class CONTENT_EXPORT AnimatedContentSampler {
- public:
-  explicit AnimatedContentSampler(base::TimeDelta min_capture_period);
-  ~AnimatedContentSampler();
-
-  // Examines the given presentation event metadata, along with recent history,
-  // to detect animated content, updating the state of this sampler.
-  // |damage_rect| is the region of a frame about to be drawn, while
-  // |event_time| refers to the frame's estimated presentation time.
-  void ConsiderPresentationEvent(const gfx::Rect& damage_rect,
-                                 base::TimeTicks event_time);
-
-  // Returns true if animated content has been detected and a decision has been
-  // made about whether to sample the last event.
-  bool HasProposal() const;
-
-  // Returns true if the last event considered should be sampled.
-  bool ShouldSample() const;
-
-  // Returns a frame timestamp to provide to consumers of the sampled frame.
-  // Only valid when should_sample() returns true.
-  base::TimeTicks frame_timestamp() const { return frame_timestamp_; }
-
-  // Accessors to currently-detected animating region/period, for logging.
-  const gfx::Rect& detected_region() const { return detected_region_; }
-  base::TimeDelta detected_period() const { return detected_period_; }
-
-  // Records that a frame with the given |frame_timestamp| was sampled.  This
-  // method should be called when *any* sampling is taken, even if it was not
-  // proposed by AnimatedContentSampler.
-  void RecordSample(base::TimeTicks frame_timestamp);
-
- private:
-  friend class AnimatedContentSamplerTest;
-
-  // Data structure for efficient online analysis of recent event history.
-  struct Observation {
-    gfx::Rect damage_rect;
-    base::TimeTicks event_time;
-
-    Observation(const gfx::Rect& d, base::TimeTicks e)
-        : damage_rect(d), event_time(e) {}
-  };
-  typedef std::deque<Observation> ObservationFifo;
-
-  // Adds an observation to |observations_|, and prunes-out the old ones.
-  void AddObservation(const gfx::Rect& damage_rect, base::TimeTicks event_time);
-
-  // Returns the damage Rect that is responsible for the majority of the pixel
-  // damage in recent event history, if there is such a Rect.  If there isn't,
-  // this method could still return any Rect, so the caller must confirm the
-  // returned Rect really is responsible for the majority of pixel damage.
-  gfx::Rect ElectMajorityDamageRect() const;
-
-  // Analyzes the observations relative to the current |event_time| to detect
-  // stable animating content.  If detected, returns true and sets the output
-  // arguments to the region of the animating content and its mean frame
-  // duration.
-  bool AnalyzeObservations(base::TimeTicks event_time,
-                           gfx::Rect* rect,
-                           base::TimeDelta* period) const;
-
-  // Called by ConsiderPresentationEvent() when the current event is part of a
-  // detected animation, to update |frame_timestamp_|.
-  void UpdateFrameTimestamp(base::TimeTicks event_time);
-
-  // The client expects frame timestamps to be at least this far apart.
-  const base::TimeDelta min_capture_period_;
-
-  // A recent history of observations in chronological order, maintained by
-  // AddObservation().
-  ObservationFifo observations_;
-
-  // The region of currently-detected animated content.  If empty, that means
-  // "not detected."
-  gfx::Rect detected_region_;
-
-  // The mean frame duration of currently-detected animated content.  If zero,
-  // that means "not detected."
-  base::TimeDelta detected_period_;
-
-  // The rewritten frame timestamp for the latest event.
-  base::TimeTicks frame_timestamp_;
-
-  // The frame timestamp provided in the last call to RecordSample().  This
-  // timestamp may or may not have been one proposed by AnimatedContentSampler.
-  base::TimeTicks recorded_frame_timestamp_;
-
-  // Accumulates all the time advancements since the last call to
-  // RecordSample().  When this is greater than zero, there have been one or
-  // more events proposed for sampling, but not yet recorded.  This accounts for
-  // the cases where AnimatedContentSampler indicates a frame should be sampled,
-  // but the client chooses not to do so.
-  base::TimeDelta sequence_offset_;
-
-  // A token bucket that is used to decide which frames to drop whenever
-  // |detected_period_| is less than |min_capture_period_|.
-  base::TimeDelta borrowed_time_;
-};
-
 // 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