Standardize usage of virtual/override/final specifiers.

chrome/browser/themes/theme_service_aurax11.cc

Index: chrome/browser/themes/theme_service_aurax11.cc
diff --git a/chrome/browser/themes/theme_service_aurax11.cc b/chrome/browser/themes/theme_service_aurax11.cc
index bc5209401502321225a33131414085634e6225c5..7f25e50053d4e7bc1cba4ba21c31072ef831928e 100644
--- a/chrome/browser/themes/theme_service_aurax11.cc
+++ b/chrome/browser/themes/theme_service_aurax11.cc
@@ -20,14 +20,14 @@ class SystemThemeX11 : public CustomThemeSupplier {
   explicit SystemThemeX11(PrefService* pref_service);
 
   // Overridden from CustomThemeSupplier:
-  virtual void StartUsingTheme() override;
-  virtual void StopUsingTheme() override;
-  virtual bool GetColor(int id, SkColor* color) const override;
-  virtual gfx::Image GetImageNamed(int id) override;
-  virtual bool HasCustomImage(int id) const override;
+  void StartUsingTheme() override;
+  void StopUsingTheme() override;
+  bool GetColor(int id, SkColor* color) const override;
+  gfx::Image GetImageNamed(int id) override;
+  bool HasCustomImage(int id) const override;
 
  private:
-  virtual ~SystemThemeX11();
+  ~SystemThemeX11() override;
 
   // These pointers are not owned by us.
   views::LinuxUI* const linux_ui_;