MSE: Cleanup WebM tracks parser initialization

media/formats/webm/webm_tracks_parser.h

Index: media/formats/webm/webm_tracks_parser.h
diff --git a/media/formats/webm/webm_tracks_parser.h b/media/formats/webm/webm_tracks_parser.h
index 6286b2303e0fa02280e246393fbf6bbc997f2c1c..7867de72abe5a81ef4ff1457710fd2071a04d3a2 100644
--- a/media/formats/webm/webm_tracks_parser.h
+++ b/media/formats/webm/webm_tracks_parser.h
@@ -88,6 +88,9 @@ class MEDIA_EXPORT WebMTracksParser : public WebMParserClient {
   }
 
  private:
+  void Reset();
+  void ResetTrackEntry();
+
   // WebMParserClient implementation.
   WebMParserClient* OnListStart(int id) override;
   bool OnListEnd(int id) override;
@@ -96,6 +99,7 @@ class MEDIA_EXPORT WebMTracksParser : public WebMParserClient {
   bool OnBinary(int id, const uint8_t* data, int size) override;
   bool OnString(int id, const std::string& str) override;
 
+  bool reset_on_next_parse_;
   int64_t track_type_;
   int64_t track_num_;
   std::string track_name_;