Standardize usage of virtual/override/final specifiers.

ash/tooltips/tooltip_controller_unittest.cc

Index: ash/tooltips/tooltip_controller_unittest.cc
diff --git a/ash/tooltips/tooltip_controller_unittest.cc b/ash/tooltips/tooltip_controller_unittest.cc
index 54b6271f02a1f7626669e4e706561a535b6abb98..824018568207a8a2fb79f856d5e416a116a58fca 100644
--- a/ash/tooltips/tooltip_controller_unittest.cc
+++ b/ash/tooltips/tooltip_controller_unittest.cc
@@ -74,9 +74,9 @@ TooltipController* GetController() {
 class TooltipControllerTest : public AshTestBase {
  public:
   TooltipControllerTest() {}
-  virtual ~TooltipControllerTest() {}
+  ~TooltipControllerTest() override {}
 
-  virtual void SetUp() override {
+  void SetUp() override {
     AshTestBase::SetUp();
     helper_.reset(new TooltipControllerTestHelper(GetController()));
   }