Revert of Adding new media controls to MediaNotification

content/public/browser/media_session_observer.h

Index: content/public/browser/media_session_observer.h
diff --git a/content/public/browser/media_session_observer.h b/content/public/browser/media_session_observer.h
index 781c65a52f94a4aca759eb5f2735b5d6fa968f98..adfeeb0a672d1e42cc9a07599e993e07760ebb21 100644
--- a/content/public/browser/media_session_observer.h
+++ b/content/public/browser/media_session_observer.h
@@ -9,12 +9,6 @@
 #include "base/optional.h"
 #include "content/common/content_export.h"
 #include "content/public/common/media_metadata.h"
-
-namespace blink {
-namespace mojom {
-enum class MediaSessionAction;
-}  // namespace mojom
-}  // namespace blink
 
 namespace content {
 
@@ -41,14 +35,6 @@
   virtual void MediaSessionMetadataChanged(
       const base::Optional<MediaMetadata>& metadata) {}
 
-  // Called when media session action is enabled.
-  virtual void MediaSessionEnabledAction(
-      blink::mojom::MediaSessionAction action) {}
-
-  // Called when media session action is disabled.
-  virtual void MediaSessionDisabledAction(
-      blink::mojom::MediaSessionAction action) {}
-
  protected:
   // Create a MediaSessionObserver and start observing a session.
   MediaSessionObserver(MediaSession* media_session);