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

ash/display/display_error_observer_chromeos_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/display/display_error_observer_chromeos.h"
 
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "grit/ash_strings.h"
 #include "ui/aura/window.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
 
 class DisplayErrorObserverTest : public test::AshTestBase {
  protected:
   DisplayErrorObserverTest() {
   }
 
-  virtual ~DisplayErrorObserverTest() {
-  }
+  ~DisplayErrorObserverTest() override {}
 
-  virtual void SetUp() override {
+  void SetUp() override {
     test::AshTestBase::SetUp();
     observer_.reset(new DisplayErrorObserver());
   }
 
  protected:
   DisplayErrorObserver* observer() { return observer_.get(); }
 
   base::string16 GetMessageContents() {
     return observer_->GetTitleOfDisplayErrorNotificationForTest();
   }
@@ skipping 38 matching lines @@
   EXPECT_EQ(l10n_util::GetStringUTF16(IDS_ASH_DISPLAY_FAILURE_ON_MIRRORING),
             GetMessageContents());
 
   observer()->OnDisplayModeChangeFailed(
       ui::MULTIPLE_DISPLAY_STATE_DUAL_EXTENDED);
   EXPECT_EQ(l10n_util::GetStringUTF16(IDS_ASH_DISPLAY_FAILURE_ON_NON_MIRRORING),
             GetMessageContents());
 }
 
 }  // namespace ash