Standardize usage of virtual/override/final specifiers.

chrome/browser/ui/views/dropdown_bar_view.cc

Index: chrome/browser/ui/views/dropdown_bar_view.cc
diff --git a/chrome/browser/ui/views/dropdown_bar_view.cc b/chrome/browser/ui/views/dropdown_bar_view.cc
index 23cc922a1126c4d7ff2fdcf12346e8abaf120eb4..7f1fbb2533fd21e3f2e64ad02f9e7c952e0f556e 100644
--- a/chrome/browser/ui/views/dropdown_bar_view.cc
+++ b/chrome/browser/ui/views/dropdown_bar_view.cc
@@ -31,10 +31,10 @@ class DropdownBackground : public views::Background {
   explicit DropdownBackground(BrowserView* browser,
                               const gfx::ImageSkia* left_alpha_mask,
                               const gfx::ImageSkia* right_alpha_mask);
-  virtual ~DropdownBackground() {}
+  ~DropdownBackground() override {}
 
   // Overridden from views::Background.
-  virtual void Paint(gfx::Canvas* canvas, views::View* view) const override;
+  void Paint(gfx::Canvas* canvas, views::View* view) const override;
 
  private:
   BrowserView* browser_view_;