Standardize usage of virtual/override/final in content/browser/

content/browser/media/capture/web_contents_audio_muter.cc

Index: content/browser/media/capture/web_contents_audio_muter.cc
diff --git a/content/browser/media/capture/web_contents_audio_muter.cc b/content/browser/media/capture/web_contents_audio_muter.cc
index 3a0d0018ccd4e46d9b1d1fc446ac4277bcddb6be..4d321927a4f9217be710bd0fd7f177e710864e22 100644
--- a/content/browser/media/capture/web_contents_audio_muter.cc
+++ b/content/browser/media/capture/web_contents_audio_muter.cc
@@ -33,17 +33,17 @@ class AudioDiscarder : public media::AudioOutputStream {
       : consumer_(media::AudioManager::Get()->GetWorkerTaskRunner(), params) {}
 
   // AudioOutputStream implementation.
-  virtual bool Open() override { return true; }
-  virtual void Start(AudioSourceCallback* callback) override {
+  bool Open() override { return true; }
+  void Start(AudioSourceCallback* callback) override {
     consumer_.Start(base::Bind(&AudioDiscarder::FetchAudioData, callback));
   }
-  virtual void Stop() override { consumer_.Stop(); }
-  virtual void SetVolume(double volume) override {}
-  virtual void GetVolume(double* volume) override { *volume = 0; }
-  virtual void Close() override { delete this; }
+  void Stop() override { consumer_.Stop(); }
+  void SetVolume(double volume) override {}
+  void GetVolume(double* volume) override { *volume = 0; }
+  void Close() override { delete this; }
 
  private:
-  virtual ~AudioDiscarder() {}
+  ~AudioDiscarder() override {}
 
   static void FetchAudioData(AudioSourceCallback* callback,
                              media::AudioBus* audio_bus) {
@@ -73,11 +73,10 @@ class WebContentsAudioMuter::MuteDestination
 
   typedef AudioMirroringManager::SourceFrameRef SourceFrameRef;
 
-  virtual ~MuteDestination() {}
+  ~MuteDestination() override {}
 
-  virtual void QueryForMatches(
-      const std::set<SourceFrameRef>& candidates,
-      const MatchesCallback& results_callback) override {
+  void QueryForMatches(const std::set<SourceFrameRef>& candidates,
+                       const MatchesCallback& results_callback) override {
     BrowserThread::PostTask(
         BrowserThread::UI,
         FROM_HERE,
@@ -104,7 +103,7 @@ class WebContentsAudioMuter::MuteDestination
     results_callback.Run(matches);
   }
 
-  virtual media::AudioOutputStream* AddInput(
+  media::AudioOutputStream* AddInput(
       const media::AudioParameters& params) override {
     return new AudioDiscarder(params);
   }