Update {virtual,override,final} to follow C++11 style in chrome/browser/chromeos/login.

chrome/browser/chromeos/login/error_screens_histogram_helper_unittest.cc

 // Copyright 2014 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 "chrome/browser/chromeos/login/error_screens_histogram_helper.h"
 
 #include "base/metrics/statistics_recorder.h"
 #include "base/test/histogram_tester.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace chromeos {
 
 class ErrorScreensHistogramHelperTest : public testing::Test {
  public:
-  virtual void SetUp() override {
+  void SetUp() override {
     helper_.reset(new ErrorScreensHistogramHelper("TestScreen"));
     second_helper_.reset(new ErrorScreensHistogramHelper("TestScreen2"));
   }
 
   content::TestBrowserThreadBundle thread_bundle_;
   base::HistogramTester histograms_;
   scoped_ptr<ErrorScreensHistogramHelper> helper_;
   scoped_ptr<ErrorScreensHistogramHelper> second_helper_;
 };
 
@@ skipping 79 matching lines @@
   now += base::TimeDelta::FromMilliseconds(1000);
   helper_->OnErrorShowTime(ErrorScreen::ERROR_STATE_PORTAL, now);
   now += base::TimeDelta::FromMilliseconds(1000);
   helper_->OnErrorHideTime(now);
   helper_.reset();
   histograms_.ExpectUniqueSample(
       "OOBE.ErrorScreensTime.TestScreen.Portal", 2000, 1);
 }
 
 }  // namespace chromeos