Standardize usage of virtual/override/final specifiers.

components/user_manager/empty_user_info.h

Index: components/user_manager/empty_user_info.h
diff --git a/components/user_manager/empty_user_info.h b/components/user_manager/empty_user_info.h
index 01dcfbf24359364ccda7cdb14b5eabe3a3faa78d..52d677c3e2fd0ba65dc2b64aad667696a804b847 100644
--- a/components/user_manager/empty_user_info.h
+++ b/components/user_manager/empty_user_info.h
@@ -19,14 +19,14 @@ namespace user_manager {
 class USER_MANAGER_EXPORT EmptyUserInfo : public UserInfo {
  public:
   EmptyUserInfo();
-  virtual ~EmptyUserInfo();
+  ~EmptyUserInfo() override;
 
   // UserInfo:
-  virtual base::string16 GetDisplayName() const override;
-  virtual base::string16 GetGivenName() const override;
-  virtual std::string GetEmail() const override;
-  virtual std::string GetUserID() const override;
-  virtual const gfx::ImageSkia& GetImage() const override;
+  base::string16 GetDisplayName() const override;
+  base::string16 GetGivenName() const override;
+  std::string GetEmail() const override;
+  std::string GetUserID() const override;
+  const gfx::ImageSkia& GetImage() const override;
 
  private:
   const gfx::ImageSkia null_image_;