Enable -Winconsistent-missing-override flag.

webrtc/api/mediastream.h

 /*
  *  Copyright 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 13 matching lines @@
 class MediaStream : public Notifier<MediaStreamInterface> {
  public:
   static rtc::scoped_refptr<MediaStream> Create(const std::string& label);
 
   std::string label() const override { return label_; }
 
   bool AddTrack(AudioTrackInterface* track) override;
   bool AddTrack(VideoTrackInterface* track) override;
   bool RemoveTrack(AudioTrackInterface* track) override;
   bool RemoveTrack(VideoTrackInterface* track) override;
-  virtual rtc::scoped_refptr<AudioTrackInterface>
-      FindAudioTrack(const std::string& track_id);
-  virtual rtc::scoped_refptr<VideoTrackInterface>
-      FindVideoTrack(const std::string& track_id);
+  rtc::scoped_refptr<AudioTrackInterface>
+      FindAudioTrack(const std::string& track_id) override;
+  rtc::scoped_refptr<VideoTrackInterface>
+      FindVideoTrack(const std::string& track_id) override;
 
   AudioTrackVector GetAudioTracks() override { return audio_tracks_; }
   VideoTrackVector GetVideoTracks() override { return video_tracks_; }
 
  protected:
   explicit MediaStream(const std::string& label);
 
  private:
   template <typename TrackVector, typename Track>
   bool AddTrack(TrackVector* Tracks, Track* track);
   template <typename TrackVector>
   bool RemoveTrack(TrackVector* Tracks, MediaStreamTrackInterface* track);
 
   std::string label_;
   AudioTrackVector audio_tracks_;
   VideoTrackVector video_tracks_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_MEDIASTREAM_H_