Standardize usage of virtual/override/final in extensions/

extensions/browser/api/declarative/test_rules_registry.h

Index: extensions/browser/api/declarative/test_rules_registry.h
diff --git a/extensions/browser/api/declarative/test_rules_registry.h b/extensions/browser/api/declarative/test_rules_registry.h
index 3d35c2b32d35741ce33af005a1384aa2c8bdfdd7..d42877f1c6a663ac69d5b0408d269a687af11a36 100644
--- a/extensions/browser/api/declarative/test_rules_registry.h
+++ b/extensions/browser/api/declarative/test_rules_registry.h
@@ -23,21 +23,20 @@ class TestRulesRegistry : public RulesRegistry {
       const WebViewKey& webview_key);
 
   // RulesRegistry implementation:
-  virtual std::string AddRulesImpl(
+  std::string AddRulesImpl(
       const std::string& extension_id,
-      const std::vector<linked_ptr<RulesRegistry::Rule> >& rules) override;
-  virtual std::string RemoveRulesImpl(
+      const std::vector<linked_ptr<RulesRegistry::Rule>>& rules) override;
+  std::string RemoveRulesImpl(
       const std::string& extension_id,
       const std::vector<std::string>& rule_identifiers) override;
-  virtual std::string RemoveAllRulesImpl(
-      const std::string& extension_id) override;
+  std::string RemoveAllRulesImpl(const std::string& extension_id) override;
 
   // Sets the result message that will be returned by the next call of
   // AddRulesImpl, RemoveRulesImpl and RemoveAllRulesImpl.
   void SetResult(const std::string& result);
 
  protected:
-  virtual ~TestRulesRegistry();
+  ~TestRulesRegistry() override;
 
  private:
   // The string that gets returned by the implementation functions of