Standardize usage of virtual/override/final in chrome/browser/

chrome/browser/metrics/field_trial_synchronizer.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_METRICS_FIELD_TRIAL_SYNCHRONIZER_H_
 #define CHROME_BROWSER_METRICS_FIELD_TRIAL_SYNCHRONIZER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 27 matching lines @@
   // the given field trail (|field_trial_name|). This is called on UI thread.
   void NotifyAllRenderers(const std::string& field_trial_name,
                           const std::string& group_name);
 
   // FieldTrialList::Observer methods:
 
   // This method is called by the FieldTrialList singleton when a trial's group
   // is finalized. This method contacts all renderers (by calling
   // NotifyAllRenderers) to create a FieldTrial that carries the randomly
   // selected state from the browser process into all the renderer processes.
-  virtual void OnFieldTrialGroupFinalized(
-      const std::string& name,
-      const std::string& group_name) override;
+  void OnFieldTrialGroupFinalized(const std::string& name,
+                                  const std::string& group_name) override;
 
  private:
   friend class base::RefCountedThreadSafe<FieldTrialSynchronizer>;
-  virtual ~FieldTrialSynchronizer();
+  ~FieldTrialSynchronizer() override;
 
   DISALLOW_COPY_AND_ASSIGN(FieldTrialSynchronizer);
 };
 
 #endif  // CHROME_BROWSER_METRICS_FIELD_TRIAL_SYNCHRONIZER_H_