Update {virtual,override,final} to follow C++11 style in ash.

ash/system/chromeos/power/tray_power_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/system/chromeos/power/tray_power.h"
 
 #include "ash/ash_switches.h"
 #include "ash/test/ash_test_base.h"
 #include "base/memory/scoped_ptr.h"
 #include "chromeos/dbus/power_manager/power_supply_properties.pb.h"
 #include "ui/message_center/fake_message_center.h"
 
 using message_center::Notification;
 using power_manager::PowerSupplyProperties;
 
 namespace {
 
 class MockMessageCenter : public message_center::FakeMessageCenter {
  public:
   MockMessageCenter() : add_count_(0), remove_count_(0) {}
-  virtual ~MockMessageCenter() {}
+  ~MockMessageCenter() override {}
 
   int add_count() const { return add_count_; }
   int remove_count() const { return remove_count_; }
 
   // message_center::FakeMessageCenter overrides:
-  virtual void AddNotification(scoped_ptr<Notification> notification) override {
+  void AddNotification(scoped_ptr<Notification> notification) override {
     add_count_++;
   }
-  virtual void RemoveNotification(const std::string& id, bool by_user)
-      override {
+  void RemoveNotification(const std::string& id, bool by_user) override {
     remove_count_++;
   }
 
  private:
   int add_count_;
   int remove_count_;
 
   DISALLOW_COPY_AND_ASSIGN(MockMessageCenter);
 };
 
 }  // namespace
 
 namespace ash {
 
 class TrayPowerTest : public test::AshTestBase {
  public:
   TrayPowerTest() {}
-  virtual ~TrayPowerTest() {}
+  ~TrayPowerTest() override {}
 
   MockMessageCenter* message_center() { return message_center_.get(); }
   TrayPower* tray_power() { return tray_power_.get(); }
 
   // test::AshTestBase::SetUp() overrides:
-  virtual void SetUp() override {
+  void SetUp() override {
     test::AshTestBase::SetUp();
     message_center_.reset(new MockMessageCenter());
     tray_power_.reset(new TrayPower(NULL, message_center_.get()));
   }
 
-  virtual void TearDown() override {
+  void TearDown() override {
     tray_power_.reset();
     message_center_.reset();
     test::AshTestBase::TearDown();
   }
 
   TrayPower::NotificationState notification_state() const {
     return tray_power_->notification_state_;
   }
 
   bool MaybeShowUsbChargerNotification(const PowerSupplyProperties& proto) {
@@ skipping 141 matching lines @@
 
   PowerSupplyProperties safe_usb = DefaultPowerSupplyProperties();
   safe_usb.set_external_power(
       power_manager::PowerSupplyProperties_ExternalPower_USB);
   safe_usb.set_battery_percent(TrayPower::kNoWarningPercentage - 0.1);
   EXPECT_FALSE(UpdateNotificationState(safe_usb));
   EXPECT_EQ(TrayPower::NOTIFICATION_NONE, notification_state());
 }
 
 }  // namespace ash