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

chrome/browser/android/thumbnail/thumbnail_store.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_THUMBNAIL_THUMBNAIL_STORE_H_
 #define CHROME_BROWSER_ANDROID_THUMBNAIL_THUMBNAIL_STORE_H_
 
 #include <list>
 #include <set>
 #include <string>
@@ skipping 32 matching lines @@
 
 class ThumbnailStore : ThumbnailDelegate {
  public:
   ThumbnailStore(const std::string& disk_cache_path_str,
                  size_t default_cache_size,
                  size_t approximation_cache_size,
                  size_t compression_queue_max_size,
                  size_t write_queue_max_size,
                  bool use_approximation_thumbnail);
 
-  virtual ~ThumbnailStore();
+  ~ThumbnailStore() override;
 
   void SetUIResourceProvider(ui::UIResourceProvider* ui_resource_provider);
 
   void AddThumbnailStoreObserver(ThumbnailStoreObserver* observer);
   void RemoveThumbnailStoreObserver(
       ThumbnailStoreObserver* observer);
 
   void Put(TabId tab_id, const SkBitmap& bitmap, float thumbnail_scale);
   void Remove(TabId tab_id);
   Thumbnail* Get(TabId tab_id, bool force_disk_read, bool allow_approximation);
 
   void RemoveFromDiskAtAndAboveId(TabId min_id);
   void InvalidateThumbnailIfChanged(TabId tab_id, const GURL& url);
   bool CheckAndUpdateThumbnailMetaData(TabId tab_id, const GURL& url);
   void UpdateVisibleIds(const TabIdList& priority);
   void DecompressThumbnailFromFile(
       TabId tab_id,
       const base::Callback<void(bool, SkBitmap)>&
           post_decompress_callback);
 
   // ThumbnailDelegate implementation
-  virtual void InvalidateCachedThumbnail(Thumbnail* thumbnail) override;
+  void InvalidateCachedThumbnail(Thumbnail* thumbnail) override;
 
  private:
   class ThumbnailMetaData {
    public:
     ThumbnailMetaData();
     ThumbnailMetaData(const base::Time& current_time, const GURL& url);
     const GURL& url() const { return url_; }
     base::Time capture_time() const { return capture_time_; }
 
    private:
@@ skipping 74 matching lines @@
   TabIdList visible_ids_;
 
   ui::UIResourceProvider* ui_resource_provider_;
 
   base::WeakPtrFactory<ThumbnailStore> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ThumbnailStore);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_THUMBNAIL_THUMBNAIL_STORE_H_