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

chrome/browser/browsing_data/browsing_data_quota_helper_impl.h

Index: chrome/browser/browsing_data/browsing_data_quota_helper_impl.h
diff --git a/chrome/browser/browsing_data/browsing_data_quota_helper_impl.h b/chrome/browser/browsing_data/browsing_data_quota_helper_impl.h
index 90127b187e30d0c2e62d25915d897f73ccb7dc6c..4cd6108fb5e4130e7ec97e62855029a6c9d73b94 100644
--- a/chrome/browser/browsing_data/browsing_data_quota_helper_impl.h
+++ b/chrome/browser/browsing_data/browsing_data_quota_helper_impl.h
@@ -27,14 +27,14 @@ class QuotaManager;
 // IO thread, we have to communicate over thread using PostTask.
 class BrowsingDataQuotaHelperImpl : public BrowsingDataQuotaHelper {
  public:
-  virtual void StartFetching(const FetchResultCallback& callback) override;
-  virtual void RevokeHostQuota(const std::string& host) override;
+  void StartFetching(const FetchResultCallback& callback) override;
+  void RevokeHostQuota(const std::string& host) override;
 
  private:
   BrowsingDataQuotaHelperImpl(base::MessageLoopProxy* ui_thread,
                               base::MessageLoopProxy* io_thread,
                               storage::QuotaManager* quota_manager);
-  virtual ~BrowsingDataQuotaHelperImpl();
+  ~BrowsingDataQuotaHelperImpl() override;
 
   void FetchQuotaInfo();