Standardize usage of virtual/override/final in media/

media/video/capture/file_video_capture_device.h

Index: media/video/capture/file_video_capture_device.h
diff --git a/media/video/capture/file_video_capture_device.h b/media/video/capture/file_video_capture_device.h
index 85c63d940fa5ea64e573b0f930177d065a5c0466..7b6cd1d848dae86f05fe81c762a08b27db147265 100644
--- a/media/video/capture/file_video_capture_device.h
+++ b/media/video/capture/file_video_capture_device.h
@@ -35,11 +35,10 @@ class MEDIA_EXPORT FileVideoCaptureDevice : public VideoCaptureDevice {
   explicit FileVideoCaptureDevice(const base::FilePath& file_path);
 
   // VideoCaptureDevice implementation, class methods.
-  virtual ~FileVideoCaptureDevice();
-  virtual void AllocateAndStart(
-      const VideoCaptureParams& params,
-      scoped_ptr<VideoCaptureDevice::Client> client) override;
-  virtual void StopAndDeAllocate() override;
+  ~FileVideoCaptureDevice() override;
+  void AllocateAndStart(const VideoCaptureParams& params,
+                        scoped_ptr<VideoCaptureDevice::Client> client) override;
+  void StopAndDeAllocate() override;
 
  private:
   // Returns size in bytes of an I420 frame, not including possible paddings,