[Android,VideoFling] Never add null players to alternative ones

chrome/browser/media/android/remote/remote_media_player_manager.h

 // Copyright 2013 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 CHROME_BROWSER_MEDIA_ANDROID_REMOTE_REMOTE_MEDIA_PLAYER_MANAGER_H_
 #define CHROME_BROWSER_MEDIA_ANDROID_REMOTE_REMOTE_MEDIA_PLAYER_MANAGER_H_
 
 #include <memory>
 #include <set>
 #include <unordered_map>
@@ skipping 86 matching lines @@
   int GetTabId();
 
   // Get the player that is not currently selected
   ScopedVector<media::MediaPlayerAndroid>::iterator GetAlternativePlayer(
       int player_id);
 
   // Get the remote player for a given player id, whether or not it is currently
   // playing remotely.
   RemoteMediaPlayerBridge* GetRemotePlayer(int player_id);
 
-  void SwapCurrentPlayer(int player_id);
+  bool SwapCurrentPlayer(int player_id);
 
   void FetchPosterBitmap(int player_id);
 
   // Contains the alternative players that are not currently in use, i.e. the
   // remote players for videos that are playing locally, and the local players
   // for videos that are playing remotely.
   ScopedVector<media::MediaPlayerAndroid> alternative_players_;
 
   std::set<int> players_playing_remotely_;
   std::unordered_map<int, GURL> poster_urls_;
 
   base::WeakPtrFactory<RemoteMediaPlayerManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RemoteMediaPlayerManager);
 };
 
 } // namespace remote_media
 
 #endif  // CHROME_BROWSER_MEDIA_ANDROID_REMOTE_REMOTE_MEDIA_PLAYER_MANAGER_H_