Return false if PeerConnection::GetStats() is called on invalid tracks

webrtc/api/statscollector.h

 /*
  *  Copyright 2012 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 60 matching lines @@
   void GetStats(MediaStreamTrackInterface* track,
                 StatsReports* reports);
 
   // Prepare a local or remote SSRC report for the given ssrc. Used internally
   // in the ExtractStatsFromList template.
   StatsReport* PrepareReport(bool local,
                              uint32_t ssrc,
                              const StatsReport::Id& transport_id,
                              StatsReport::Direction direction);
 
+  // A track is invalid if there is no report data for it.
+  bool IsValidTrack(const std::string& track_id);
+
   // Method used by the unittest to force a update of stats since UpdateStats()
   // that occur less than kMinGatherStatsPeriod number of ms apart will be
   // ignored.
   void ClearUpdateStatsCacheForTest();
 
  private:
   friend class StatsCollectorTest;
 
   // Overridden in unit tests to fake timing.
   virtual double GetTimeNow();
@@ skipping 49 matching lines @@
   // TODO(tommi): We appear to be holding on to raw pointers to reference
   // counted objects?  We should be using scoped_refptr here.
   typedef std::vector<std::pair<AudioTrackInterface*, uint32_t> >
       LocalAudioTrackVector;
   LocalAudioTrackVector local_audio_tracks_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_STATSCOLLECTOR_H_