Update {virtual,override} to follow C++11 style in remoting.

remoting/host/audio_capturer_win.h

Index: remoting/host/audio_capturer_win.h
diff --git a/remoting/host/audio_capturer_win.h b/remoting/host/audio_capturer_win.h
index c9f19d3cf3d3432cc898c0cc68156f25a7729cdd..49477fadac9d0f357ea77c96d4e635f0438ea713 100644
--- a/remoting/host/audio_capturer_win.h
+++ b/remoting/host/audio_capturer_win.h
@@ -23,10 +23,10 @@ namespace remoting {
 class AudioCapturerWin : public AudioCapturer {
  public:
   AudioCapturerWin();
-  virtual ~AudioCapturerWin();
+  ~AudioCapturerWin() override;
 
   // AudioCapturer interface.
-  virtual bool Start(const PacketCapturedCallback& callback) override;
+  bool Start(const PacketCapturedCallback& callback) override;
 
  private:
   // Receives all packets from the audio capture endpoint buffer and pushes them