content/browser/renderer_host/media/media_stream_track_metrics_host.h

// 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 CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_TRACK_METRICS_HOST_H_
#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_TRACK_METRICS_HOST_H_

#include <map>
#include <string>

#include "base/time/time.h"
#include "content/public/browser/browser_message_filter.h"

namespace content {

// Responsible for logging metrics about audio and video track
// lifetimes. These are based on messages from the renderer that are
// sent when tracks are created and destroyed. Unfortunately we can't
// reliably log the lifetime metric in the renderer because that
// process may be destroyed at any time by the fast shutdown path (see
// RenderProcessHost::FastShutdownIfPossible).
//
// There is one instance of this class per render process.
//
// If the renderer process goes away without sending messages that
// tracks were removed, this class instead infers that the tracks were
// removed.
class MediaStreamTrackMetricsHost
    : public BrowserMessageFilter {
 public:
  explicit MediaStreamTrackMetricsHost();

 protected:
  ~MediaStreamTrackMetricsHost() override;

  // BrowserMessageFilter override.
  bool OnMessageReceived(const IPC::Message& message) override;

 private:
  void OnAddTrack(uint64 id, bool is_audio, bool is_remote);
  void OnRemoveTrack(uint64 id);

  // Information for a track we're keeping in |tracks_|. |is_audio|
  // specifies whether it's an audio or video track, |is_remote|
  // specifies whether it's remote (received over a PeerConnection) or
  // local (sent over a PeerConnection). |timestamp| specifies when
  // the track was connected.
  struct TrackInfo {
    bool is_audio;
    bool is_remote;
    base::TimeTicks timestamp;
  };

  void ReportDuration(const TrackInfo& info);

  // Values are unique (per renderer) track IDs.
  typedef std::map<uint64, TrackInfo> TrackMap;
  TrackMap tracks_;
};

}  // namespace content

#endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_TRACK_METRICS_HOST_H_