[Chromecast] Fix media session blocking tests.

content/browser/media/session/media_session_impl.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_IMPL_H_
 #define CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_IMPL_H_
 
 #include <stddef.h>
 
 #include <map>
+#include <memory>
 #include <set>
 
 #include "base/callback_list.h"
 #include "base/id_map.h"
 #include "base/macros.h"
 #include "base/observer_list.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"
@@ skipping 57 matching lines @@
   ~MediaSessionImpl() override;
 
 #if defined(OS_ANDROID)
   static MediaSession* FromJavaMediaSession(
       const base::android::JavaRef<jobject>& j_media_session);
   MediaSessionAndroid* session_android() const {
     return session_android_.get();
   }
 #endif  // defined(OS_ANDROID)
 
-  void AddObserver(MediaSessionObserver* observer);
-  void RemoveObserver(MediaSessionObserver* observer);
+  void AddObserver(MediaSessionObserver* observer) override;
+  void RemoveObserver(MediaSessionObserver* observer) override;
 
   void NotifyMediaSessionMetadataChange(
       const base::Optional<MediaMetadata>& metadata);
   void NotifyMediaSessionActionsChange(
       const std::set<blink::mojom::MediaSessionAction>& actions);
 
   // 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(MediaSessionPlayerObserver* observer,
@@ skipping 211 matching lines @@
   ServicesMap services_;
   // The currently routed service (non-owned pointer).
   MediaSessionServiceImpl* routed_service_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaSessionImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_IMPL_H_