chrome/browser/media/media_device_id_salt.h

   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
  14 class 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.
  22 class 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_