Make MediaSession a runtime-enabled feature on Desktop.

content/browser/media/android/media_session_observer.h

Index: content/browser/media/android/media_session_observer.h
diff --git a/content/browser/media/android/media_session_observer.h b/content/browser/media/android/media_session_observer.h
deleted file mode 100644
index ebf9bec1fe5f97d964918f7d463bf767c94efad2..0000000000000000000000000000000000000000
--- a/content/browser/media/android/media_session_observer.h
+++ /dev/null
@@ -1,29 +0,0 @@
-// 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_ANDROID_MEDIA_SESSION_OBSERVER_H_
-#define CONTENT_BROWSER_MEDIA_ANDROID_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_ANDROID_MEDIA_SESSION_OBSERVER_H_