media_observer.h revision 5d1f7b1de12d16ceb2c938c56701a3e8bfa558f7 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CONTENT_PUBLIC_BROWSER_MEDIA_OBSERVER_H_
6#define CONTENT_PUBLIC_BROWSER_MEDIA_OBSERVER_H_
7
8#include "content/public/browser/media_request_state.h"
9#include "content/public/common/media_stream_request.h"
10
11namespace content {
12
13// An embedder may implement MediaObserver and return it from
14// ContentBrowserClient to receive callbacks as media events occur.
15class MediaObserver {
16 public:
17  // Called when a audio capture device is plugged in or unplugged.
18  virtual void OnAudioCaptureDevicesChanged(
19      const MediaStreamDevices& devices) = 0;
20
21  // Called when a video capture device is plugged in or unplugged.
22  virtual void OnVideoCaptureDevicesChanged(
23      const MediaStreamDevices& devices) = 0;
24
25  // Called when a media request changes state.
26  virtual void OnMediaRequestStateChanged(
27      int render_process_id,
28      int render_view_id,
29      int page_request_id,
30      const GURL& security_origin,
31      const MediaStreamDevice& device,
32      MediaRequestState state) = 0;
33
34  // Called when an audio stream transitions into a playing or paused state, and
35  // also at regular intervals to report the current power level of the audio
36  // signal in dBFS (decibels relative to full-scale) units.  |clipped| is true
37  // if any part of the audio signal has been clipped since the last call.  See
38  // media/audio/audio_power_monitor.h for more info.
39  virtual void OnAudioStreamPlayingChanged(
40      int render_process_id,
41      int render_view_id,
42      int stream_id,
43      bool is_playing,
44      float power_dbfs,
45      bool clipped) = 0;
46
47  // Called when the audio stream is being created.
48  virtual void OnCreatingAudioStream(int render_process_id,
49                                     int render_view_id) = 0;
50
51 protected:
52  virtual ~MediaObserver() {}
53};
54
55}  // namespace content
56
57#endif  // CONTENT_PUBLIC_BROWSER_MEDIA_OBSERVER_H_
58