1// Copyright 2013 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 CHROME_BROWSER_MEDIA_MEDIA_DEVICE_ID_SALT_H_
6#define CHROME_BROWSER_MEDIA_MEDIA_DEVICE_ID_SALT_H_
7
8#include <string>
9
10#include "base/memory/ref_counted.h"
11#include "base/prefs/pref_member.h"
12#include "components/pref_registry/pref_registry_syncable.h"
13
14class PrefService;
15
16// MediaDeviceIDSalt is responsible for creating and retrieving a salt string
17// that is used for creating MediaSource IDs that can be cached by a web
18// service. If the cache is cleared, the  MediaSourceIds are invalidated.
19//
20// The class is reference counted so that it can be used in the
21// callback returned by ResourceContext::GetMediaDeviceIDSalt.
22class MediaDeviceIDSalt : public base::RefCountedThreadSafe<MediaDeviceIDSalt> {
23 public:
24  MediaDeviceIDSalt(PrefService* pref_service, bool incognito);
25  void ShutdownOnUIThread();
26
27  std::string GetSalt() const;
28
29  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
30  static void Reset(PrefService* pref_service);
31
32 private:
33  friend class base::RefCountedThreadSafe<MediaDeviceIDSalt>;
34  ~MediaDeviceIDSalt();
35
36  // |incognito_salt_| is initialized in ctor on UI thread but only read
37  //  on the IO thread.
38  std::string incognito_salt_;
39  mutable StringPrefMember media_device_id_salt_;
40
41  DISALLOW_COPY_AND_ASSIGN(MediaDeviceIDSalt);
42};
43
44#endif  // CHROME_BROWSER_MEDIA_MEDIA_DEVICE_ID_SALT_H_
45