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

content/renderer/media/webrtc_local_audio_track_unittest.cc

Index: content/renderer/media/webrtc_local_audio_track_unittest.cc
diff --git a/content/renderer/media/webrtc_local_audio_track_unittest.cc b/content/renderer/media/webrtc_local_audio_track_unittest.cc
index 79eecf00a8e8f9d56a448048a3acfb6ca1588abd..947eab1cae2b075b03e4e063d8b3590a46a49e49 100644
--- a/content/renderer/media/webrtc_local_audio_track_unittest.cc
+++ b/content/renderer/media/webrtc_local_audio_track_unittest.cc
@@ -45,10 +45,10 @@ class FakeAudioThread : public base::PlatformThread::Delegate {
     audio_bus_ = media::AudioBus::Create(params);
   }
 
-  virtual ~FakeAudioThread() { DCHECK(thread_.is_null()); }
+  ~FakeAudioThread() override { DCHECK(thread_.is_null()); }
 
   // base::PlatformThread::Delegate:
-  virtual void ThreadMain() override {
+  void ThreadMain() override {
     while (true) {
       if (closure_.IsSignaled())
         return;