Adding new media controls to MediaNotification

content/public/browser/media_session_observer.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_PUBLIC_BROWSER_MEDIA_SESSION_OBSERVER_H_
 #define CONTENT_PUBLIC_BROWSER_MEDIA_SESSION_OBSERVER_H_
 
 #include "base/macros.h"
 #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 {
 
 class MediaSession;
 class MediaSessionImpl;
 
 // The observer for observing MediaSession events.
 class CONTENT_EXPORT MediaSessionObserver {
  public:
   // Gets the observed MediaSession.
   MediaSession* media_session() const;
 
   // Called when the observed MediaSession is being destroyed. Gives subclass a
   // chance to cleanup. After the whole loop over MediaSessionObservers has been
   // finished, media_session() returns nullptr.
   virtual void MediaSessionDestroyed() {}
 
   // Called when the observed MediaSession has changed its state.
   virtual void MediaSessionStateChanged(bool is_controllable,
                                         bool is_suspended) {}
 
   // Called when the observed MediaSession has changed metadata.
   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 |session|.
   explicit MediaSessionObserver(MediaSession* session);
 
   // Destructor of MediaSessionObserver. It will remove itself from |session| if
   // the observer is still observing a MediaSession.
   virtual ~MediaSessionObserver();
 
  private:
   friend class MediaSessionImpl;
 
   void StopObserving();
 
   // Weak pointer to MediaSession.
   MediaSessionImpl* session_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaSessionObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_MEDIA_SESSION_OBSERVER_H_