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

chrome/browser/browsing_data/browsing_data_file_system_helper.h

Index: chrome/browser/browsing_data/browsing_data_file_system_helper.h
diff --git a/chrome/browser/browsing_data/browsing_data_file_system_helper.h b/chrome/browser/browsing_data/browsing_data_file_system_helper.h
index cc1e6c8f1b14857ba27ca7d45c9901d54f432f51..d3c335e6d4d398dd4a8936b67ef0168b602457a3 100644
--- a/chrome/browser/browsing_data/browsing_data_file_system_helper.h
+++ b/chrome/browser/browsing_data/browsing_data_file_system_helper.h
@@ -120,17 +120,18 @@ class CannedBrowsingDataFileSystemHelper
   }
 
   // BrowsingDataFileSystemHelper implementation.
-  virtual void StartFetching(const base::Callback<
-      void(const std::list<FileSystemInfo>&)>& callback) override;
+  void StartFetching(
+      const base::Callback<void(const std::list<FileSystemInfo>&)>& callback)
+      override;
 
   // Note that this doesn't actually have an implementation for this canned
   // class. It hasn't been necessary for anything that uses the canned
   // implementation, as the canned class is only used in tests, or in read-only
   // contexts (like the non-modal cookie dialog).
-  virtual void DeleteFileSystemOrigin(const GURL& origin) override {}
+  void DeleteFileSystemOrigin(const GURL& origin) override {}
 
  private:
-  virtual ~CannedBrowsingDataFileSystemHelper();
+  ~CannedBrowsingDataFileSystemHelper() override;
 
   // Holds the current list of filesystems returned to the client.
   std::list<FileSystemInfo> file_system_info_;