Wrap MediaMetadata in base::Optional in content and chrome

content/browser/media/session/media_session.cc

 // 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.
 
 #include "content/browser/media/session/media_session.h"
 
 #include "content/browser/media/session/media_session_delegate.h"
 #include "content/browser/media/session/media_session_observer.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/web_contents.h"
@@ skipping 42 matching lines @@
     session->Initialize();
   }
   return session;
 }
 
 MediaSession::~MediaSession() {
   DCHECK(players_.empty());
   DCHECK(audio_focus_state_ == State::INACTIVE);
 }
 
-void MediaSession::SetMetadata(const MediaMetadata& metadata) {
+void MediaSession::SetMetadata(const base::Optional<MediaMetadata>& metadata) {
   metadata_ = metadata;
   // TODO(zqzhang): On Android, the metadata is sent though JNI everytime the
   // media session play/pause state changes. Need to find a way to seprate the
   // state change and Metadata update. See https://crbug.com/621855.
   static_cast<WebContentsImpl*>(web_contents())->OnMediaSessionStateChanged();
 }
 
 bool MediaSession::AddPlayer(MediaSessionObserver* observer,
                              int player_id,
                              media::MediaContentType media_content_type) {
@@ skipping 309 matching lines @@
     case State::SUSPENDED:
       uma_helper_.OnSessionSuspended();
       break;
     case State::INACTIVE:
       uma_helper_.OnSessionInactive();
       break;
   }
 }
 
 }  // namespace content