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

content/browser/download/drag_download_file.h

Index: content/browser/download/drag_download_file.h
diff --git a/content/browser/download/drag_download_file.h b/content/browser/download/drag_download_file.h
index 5dfbcb9f080953ec406c6ab4d226c49d3608a63b..825f73668aaf3a91d0ebc33c21b4d084a0b72231 100644
--- a/content/browser/download/drag_download_file.h
+++ b/content/browser/download/drag_download_file.h
@@ -42,15 +42,15 @@ class CONTENT_EXPORT DragDownloadFile : public ui::DownloadFileProvider {
                    WebContents* web_contents);
 
   // DownloadFileProvider methods.
-  virtual void Start(ui::DownloadFileObserver* observer) override;
-  virtual bool Wait() override;
-  virtual void Stop() override;
+  void Start(ui::DownloadFileObserver* observer) override;
+  bool Wait() override;
+  void Stop() override;
 
  private:
   class DragDownloadFileUI;
   enum State {INITIALIZED, STARTED, SUCCESS, FAILURE};
 
-  virtual ~DragDownloadFile();
+  ~DragDownloadFile() override;
 
   void DownloadCompleted(bool is_successful);
   void CheckThread();