Media Remoting: UMAs to track session events and measurements.

media/remoting/metrics.h

Index: media/remoting/metrics.h
diff --git a/media/remoting/metrics.h b/media/remoting/metrics.h
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+// Copyright 2017 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_REMOTING_METRICS_H_
+#define MEDIA_REMOTING_METRICS_H_
+
+#include "base/macros.h"
+#include "base/optional.h"
+#include "base/time/time.h"
+#include "media/base/pipeline_metadata.h"
+#include "media/remoting/triggers.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace media {
+namespace remoting {
+
+class SessionMetricsRecorder {
+ public:
+  SessionMetricsRecorder();
+  ~SessionMetricsRecorder();
+
+  // When attempting to start a remoting session, WillStartSession() is called,
+  // followed by either OnSessionStartSucceeded() or OnSessionStop() to indicate
+  // whether the start succeeded. Later, OnSessionStop() is called when the
+  // session ends.
+  void WillStartSession(StartTrigger trigger);
+  void DidStartSession();
+  void WillStopSession(StopTrigger trigger);
+
+  // These may be called before, during, or after a remoting session.
+  void OnPipelineMetadataChanged(const PipelineMetadata& metadata);
+  void OnRemotePlaybackDisabled(bool disabled);
+  void OnPosterImageDownloaded(const base::TimeDelta download_duration,
+                               bool success);
+
+ private:
+  // Whether audio only, video only, or both were played during the session.
+  //
+  // NOTE: Never re-number or re-use numbers here. These are used in UMA
+  // histograms, and must remain backwards-compatible for all time. However,
+  // *do* change TRACK_CONFIGURATION_MAX to one after the greatest value when
+  // adding new ones. Also, don't forget to update histograms.xml!
+  enum TrackConfiguration {
+    NEITHER_AUDIO_NOR_VIDEO = 0,
+    AUDIO_ONLY = 1,
+    VIDEO_ONLY = 2,
+    AUDIO_AND_VIDEO = 3,
+
+    TRACK_CONFIGURATION_MAX = 3,
+  };
+
+  // Helper methods to record media configuration at relevant times.
+  void RecordAudioConfiguration();
+  void RecordVideoConfiguration();
+  void RecordTrackConfiguration();
+
+  // |start_trigger_| is set while a remoting session is active.
+  base::Optional<StartTrigger> start_trigger_;
+
+  // When the current (or last) remoting session started.
+  base::TimeTicks start_time_;
+
+  // Last known audio and video configuration. These can change before/after a
+  // remoting session as well as during one.
+  AudioCodec last_audio_codec_;
+  ChannelLayout last_channel_layout_;
+  int last_sample_rate_;
+  VideoCodec last_video_codec_;
+  VideoCodecProfile last_video_profile_;
+  gfx::Size last_natural_size_;
+
+  // Last known disabled playback state. This can change before/after a remoting
+  // session as well as during one.
+  bool remote_playback_is_disabled_;
+
+  DISALLOW_COPY_AND_ASSIGN(SessionMetricsRecorder);
+};
+
+class RendererMetricsRecorder {
+ public:
+  RendererMetricsRecorder();
+  ~RendererMetricsRecorder();
+
+  // Called when an "initialize success" message is received from the remote.
+  void OnRendererInitialized();
+
+  // Called whenever there is direct (or indirect, but close-in-time) evidence
+  // that playout has occurred.
+  void OnEvidenceOfPlayoutAtReceiver();
+
+  // These are called at regular intervals throughout the session to provide
+  // estimated data flow rates.
+  void OnAudioRateEstimate(int kilobits_per_second);
+  void OnVideoRateEstimate(int kilobits_per_second);
+
+ private:
+  const base::TimeTicks start_time_;
+  bool did_record_first_playout_;
+
+  DISALLOW_COPY_AND_ASSIGN(RendererMetricsRecorder);
+};
+
+}  // namespace remoting
+}  // namespace media
+
+#endif  // MEDIA_REMOTING_METRICS_H_