Wrap MediaMetadata in base::Optional in content and chrome

content/browser/media/session/media_session.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_H_
 #define CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_H_
 
 #include <stddef.h>
 
 #include "base/callback_list.h"
 #include "base/id_map.h"
 #include "base/macros.h"
+#include "base/optional.h"
 #include "content/browser/media/session/audio_focus_manager.h"
 #include "content/browser/media/session/media_session_uma_helper.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 #include "content/public/common/media_metadata.h"
 
 class MediaSessionBrowserTest;
 
 namespace media {
@@ skipping 33 matching lines @@
     // Suspended by the page via script or user interaction.
     CONTENT,
   };
 
   // Returns the MediaSession associated to this WebContents. Creates one if
   // none is currently available.
   CONTENT_EXPORT static MediaSession* Get(WebContents* web_contents);
 
   ~MediaSession() override;
 
-  void SetMetadata(const MediaMetadata& metadata);
-  const MediaMetadata& metadata() const { return metadata_; }
+  void SetMetadata(const base::Optional<MediaMetadata>& metadata);
+  const base::Optional<MediaMetadata>& metadata() const { return metadata_; }
 
   // Adds the given player to the current media session. Returns whether the
   // player was successfully added. If it returns false, AddPlayer() should be
   // called again later.
   CONTENT_EXPORT bool AddPlayer(MediaSessionObserver* observer,
                                 int player_id,
                                 media::MediaContentType media_content_type);
 
   // Removes the given player from the current media session. Abandons audio
   // focus if that was the last player in the session.
@@ skipping 133 matching lines @@
   SuspendType suspend_type_;
   AudioFocusManager::AudioFocusType audio_focus_type_;
 
   MediaSessionUmaHelper uma_helper_;
 
   // The ducking state of this media session. The initial value is |false|, and
   // is set to |true| after StartDucking(), and will be set to |false| after
   // StopDucking().
   bool is_ducking_;
 
-  MediaMetadata metadata_;
+  base::Optional<MediaMetadata> metadata_;
   base::CallbackList<void(State)> media_session_state_listeners_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaSession);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_H_