Fixing naming issues in MediaSession

content/browser/media/session/media_session_observer.h

-// Copyright 2015 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_MEDIA_SESSION_OBSERVER_H_
-#define CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_OBSERVER_H_
-
-namespace content {
-
-class MediaSessionObserver {
- public:
-  MediaSessionObserver() = default;
-  virtual ~MediaSessionObserver() = default;
-
-  // The given |player_id| has been suspended by the MediaSession.
-  virtual void OnSuspend(int player_id) = 0;
-
-  // The given |player_id| has been resumed by the MediaSession.
-  virtual void OnResume(int player_id) = 0;
-
-  // The given |player_id| has been set a new volume multiplier by
-  // the MediaSession.
-  virtual void OnSetVolumeMultiplier(int player_id,
-                                     double volume_multiplier) = 0;
-};
-
-}  // namespace content
-
-#endif // CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_OBSERVER_H_