Standardize usage of virtual/override/final in content/renderer/

content/renderer/stats_collection_observer.h

 // 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.
 
 #ifndef CONTENT_RENDERER_STATS_COLLECTION_OBSERVER_H_
 #define CONTENT_RENDERER_STATS_COLLECTION_OBSERVER_H_
 
 #include "base/time/time.h"
 #include "content/public/renderer/render_view_observer.h"
 
 namespace content {
 
 class RenderViewImpl;
 
 // Collect timing information for page loads.
 // If a Renderview performs multiple loads, only the first one is recorded.
 class StatsCollectionObserver : public RenderViewObserver {
  public:
   explicit StatsCollectionObserver(RenderViewImpl* render_view);
-  virtual ~StatsCollectionObserver();
+  ~StatsCollectionObserver() override;
 
   // RenderViewObserver implementation
-  virtual void DidStartLoading() override;
-  virtual void DidStopLoading() override;
+  void DidStartLoading() override;
+  void DidStopLoading() override;
 
   // Timing for the page load start and stop.  These functions may return
   // a null time value under various circumstances.
   const base::Time& load_start_time() { return start_time_; }
   const base::Time& load_stop_time() { return stop_time_; }
 
  private:
   base::Time start_time_;
   base::Time stop_time_;
 
    DISALLOW_COPY_AND_ASSIGN(StatsCollectionObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_STATS_COLLECTION_OBSERVER_H_