Decouple MediaSession messages from WebContents (full patch)

content/browser/media/session/audio_focus_manager.h

 // Copyright 2016 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_MEDIA_SESSION_AUDIO_FOCUS_MANAGER_H_
 #define CONTENT_BROWSER_MEDIA_SESSION_AUDIO_FOCUS_MANAGER_H_
 
 #include <list>
 #include <unordered_map>
 
 #include "base/memory/singleton.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
 
 namespace content {
 
-class MediaSession;
+class MediaSessionImpl;
 
 class CONTENT_EXPORT AudioFocusManager {
  public:
   enum class AudioFocusType {
     Gain,
     GainTransientMayDuck,
   };
 
   // Returns Chromium's internal AudioFocusManager.
   static AudioFocusManager* GetInstance();
 
-  void RequestAudioFocus(MediaSession* media_session, AudioFocusType type);
+  void RequestAudioFocus(MediaSessionImpl* media_session, AudioFocusType type);
 
-  void AbandonAudioFocus(MediaSession* media_session);
+  void AbandonAudioFocus(MediaSessionImpl* media_session);
 
  private:
   friend struct base::DefaultSingletonTraits<AudioFocusManager>;
   friend class AudioFocusManagerTest;
 
   AudioFocusManager();
   ~AudioFocusManager();
 
-  void MaybeRemoveFocusEntry(MediaSession* media_session);
+  void MaybeRemoveFocusEntry(MediaSessionImpl* media_session);
 
   // Weak reference of managed MediaSessions. A MediaSession must abandon audio
   // foucs before its destruction.
-  std::list<MediaSession*> audio_focus_stack_;
+  std::list<MediaSessionImpl*> audio_focus_stack_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_SESSION_AUDIO_FOCUS_MANAGER_H_