Standardize usage of virtual/override/final in media/

media/formats/webm/webm_stream_parser.h

Index: media/formats/webm/webm_stream_parser.h
diff --git a/media/formats/webm/webm_stream_parser.h b/media/formats/webm/webm_stream_parser.h
index 7a99f3a1666df41b5d430dd0cb0a312c90adb484..deefa73cca524c158cffea11b03143d498252d07 100644
--- a/media/formats/webm/webm_stream_parser.h
+++ b/media/formats/webm/webm_stream_parser.h
@@ -20,18 +20,19 @@ class WebMClusterParser;
 class WebMStreamParser : public StreamParser {
  public:
   WebMStreamParser();
-  virtual ~WebMStreamParser();
+  ~WebMStreamParser() override;
 
   // StreamParser implementation.
-  virtual void Init(const InitCB& init_cb, const NewConfigCB& config_cb,
-                    const NewBuffersCB& new_buffers_cb,
-                    bool ignore_text_tracks,
-                    const NeedKeyCB& need_key_cb,
-                    const NewMediaSegmentCB& new_segment_cb,
-                    const base::Closure& end_of_segment_cb,
-                    const LogCB& log_cb) override;
-  virtual void Flush() override;
-  virtual bool Parse(const uint8* buf, int size) override;
+  void Init(const InitCB& init_cb,
+            const NewConfigCB& config_cb,
+            const NewBuffersCB& new_buffers_cb,
+            bool ignore_text_tracks,
+            const NeedKeyCB& need_key_cb,
+            const NewMediaSegmentCB& new_segment_cb,
+            const base::Closure& end_of_segment_cb,
+            const LogCB& log_cb) override;
+  void Flush() override;
+  bool Parse(const uint8* buf, int size) override;
 
  private:
   enum State {