Standardize usage of virtual/override/final in media/

media/formats/webm/webm_video_client.h

Index: media/formats/webm/webm_video_client.h
diff --git a/media/formats/webm/webm_video_client.h b/media/formats/webm/webm_video_client.h
index 73e39552a8326753f0d02f31444bc89948756c0a..8e246d9a7849d4e2b3c6f4c226022d04a588c132 100644
--- a/media/formats/webm/webm_video_client.h
+++ b/media/formats/webm/webm_video_client.h
@@ -18,7 +18,7 @@ class VideoDecoderConfig;
 class WebMVideoClient : public WebMParserClient {
  public:
   explicit WebMVideoClient(const LogCB& log_cb);
-  virtual ~WebMVideoClient();
+  ~WebMVideoClient() override;
 
   // Reset this object's state so it can process a new video track element.
   void Reset();
@@ -37,9 +37,9 @@ class WebMVideoClient : public WebMParserClient {
 
  private:
   // WebMParserClient implementation.
-  virtual bool OnUInt(int id, int64 val) override;
-  virtual bool OnBinary(int id, const uint8* data, int size) override;
-  virtual bool OnFloat(int id, double val) override;
+  bool OnUInt(int id, int64 val) override;
+  bool OnBinary(int id, const uint8* data, int size) override;
+  bool OnFloat(int id, double val) override;
 
   LogCB log_cb_;
   int64 pixel_width_;