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

chrome/browser/browsing_data/browsing_data_channel_id_helper.h

Index: chrome/browser/browsing_data/browsing_data_channel_id_helper.h
diff --git a/chrome/browser/browsing_data/browsing_data_channel_id_helper.h b/chrome/browser/browsing_data/browsing_data_channel_id_helper.h
index 380ce9e55b15e8fcbaa12d29fb0cdf7e598827ce..520fe485742e85e2f1b8451ac9a73ca58ce53107 100644
--- a/chrome/browser/browsing_data/browsing_data_channel_id_helper.h
+++ b/chrome/browser/browsing_data/browsing_data_channel_id_helper.h
@@ -68,11 +68,11 @@ class CannedBrowsingDataChannelIDHelper
   size_t GetChannelIDCount() const;
 
   // BrowsingDataChannelIDHelper methods.
-  virtual void StartFetching(const FetchResultCallback& callback) override;
-  virtual void DeleteChannelID(const std::string& server_id) override;
+  void StartFetching(const FetchResultCallback& callback) override;
+  void DeleteChannelID(const std::string& server_id) override;
 
  private:
-  virtual ~CannedBrowsingDataChannelIDHelper();
+  ~CannedBrowsingDataChannelIDHelper() override;
 
   void FinishFetching();