Standardize usage of virtual/override/final in chrome/browser/extensions/

chrome/browser/extensions/api/media_galleries/media_galleries_api.cc

Index: chrome/browser/extensions/api/media_galleries/media_galleries_api.cc
diff --git a/chrome/browser/extensions/api/media_galleries/media_galleries_api.cc b/chrome/browser/extensions/api/media_galleries/media_galleries_api.cc
index 71ce7d6c9472c112bad63e7c07d6a8999b464f4a..d5f033dd7be350f42355ff9a2d00ab57306bfa55 100644
--- a/chrome/browser/extensions/api/media_galleries/media_galleries_api.cc
+++ b/chrome/browser/extensions/api/media_galleries/media_galleries_api.cc
@@ -274,26 +274,26 @@ class SelectDirectoryDialog : public ui::SelectFileDialog::Listener,
   }
 
   // ui::SelectFileDialog::Listener implementation.
-  virtual void FileSelected(const base::FilePath& path,
-                            int index,
-                            void* params) override {
+  void FileSelected(const base::FilePath& path,
+                    int index,
+                    void* params) override {
     callback_.Run(path);
     Release();  // Balanced in Show().
   }
 
-  virtual void MultiFilesSelected(const std::vector<base::FilePath>& files,
-                                  void* params) override {
+  void MultiFilesSelected(const std::vector<base::FilePath>& files,
+                          void* params) override {
     NOTREACHED() << "Should not be able to select multiple files";
   }
 
-  virtual void FileSelectionCanceled(void* params) override {
+  void FileSelectionCanceled(void* params) override {
     callback_.Run(base::FilePath());
     Release();  // Balanced in Show().
   }
 
  private:
   friend class base::RefCounted<SelectDirectoryDialog>;
-  virtual ~SelectDirectoryDialog() {}
+  ~SelectDirectoryDialog() override {}
 
   scoped_refptr<ui::SelectFileDialog> select_file_dialog_;
   WebContents* web_contents_;