Standardize usage of virtual/override/final specifiers.

ash/system/user/user_card_view.cc

Index: ash/system/user/user_card_view.cc
diff --git a/ash/system/user/user_card_view.cc b/ash/system/user/user_card_view.cc
index 5a240d891817f81f958ff53e05c58052d7e592c0..cb29388b39fcb51f6370ae582c60208b130fbc3a 100644
--- a/ash/system/user/user_card_view.cc
+++ b/ash/system/user/user_card_view.cc
@@ -126,16 +126,16 @@ class PublicAccountUserDetails : public views::View,
                                  public views::LinkListener {
  public:
   PublicAccountUserDetails(int max_width);
-  virtual ~PublicAccountUserDetails();
+  ~PublicAccountUserDetails() override;
 
  private:
   // Overridden from views::View.
-  virtual void Layout() override;
-  virtual gfx::Size GetPreferredSize() const override;
-  virtual void OnPaint(gfx::Canvas* canvas) override;
+  void Layout() override;
+  gfx::Size GetPreferredSize() const override;
+  void OnPaint(gfx::Canvas* canvas) override;
 
   // Overridden from views::LinkListener.
-  virtual void LinkClicked(views::Link* source, int event_flags) override;
+  void LinkClicked(views::Link* source, int event_flags) override;
 
   // Calculate a preferred size that ensures the label text and the following
   // link do not wrap over more than three lines in total for aesthetic reasons