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

ash/system/chromeos/rotation/tray_rotation_lock_unittest.cc

Index: ash/system/chromeos/rotation/tray_rotation_lock_unittest.cc
diff --git a/ash/system/chromeos/rotation/tray_rotation_lock_unittest.cc b/ash/system/chromeos/rotation/tray_rotation_lock_unittest.cc
index 246772d8d0bf8803ae5476f9db6f3d137ef1975a..f551a1b6f9f2d6ad4a8b7d8b6c0f1ddbd6628013 100644
--- a/ash/system/chromeos/rotation/tray_rotation_lock_unittest.cc
+++ b/ash/system/chromeos/rotation/tray_rotation_lock_unittest.cc
@@ -28,7 +28,7 @@ namespace ash {
 class TrayRotationLockTest : public test::AshTestBase {
  public:
   TrayRotationLockTest() {}
-  virtual ~TrayRotationLockTest() {}
+  ~TrayRotationLockTest() override {}
 
   TrayRotationLock* tray() {
     return tray_.get();