Standardize usage of virtual/override/final in extensions/

extensions/browser/content_verifier.h

Index: extensions/browser/content_verifier.h
diff --git a/extensions/browser/content_verifier.h b/extensions/browser/content_verifier.h
index 83c89b755696fe4afb04afbed7b4d98ea1721df2..47f67c1411be6c1770eac92098a63b417af67dda 100644
--- a/extensions/browser/content_verifier.h
+++ b/extensions/browser/content_verifier.h
@@ -55,18 +55,17 @@ class ContentVerifier : public base::RefCountedThreadSafe<ContentVerifier>,
                     ContentVerifyJob::FailureReason reason);
 
   // ExtensionRegistryObserver interface
-  virtual void OnExtensionLoaded(content::BrowserContext* browser_context,
-                                 const Extension* extension) override;
-  virtual void OnExtensionUnloaded(
-      content::BrowserContext* browser_context,
-      const Extension* extension,
-      UnloadedExtensionInfo::Reason reason) override;
+  void OnExtensionLoaded(content::BrowserContext* browser_context,
+                         const Extension* extension) override;
+  void OnExtensionUnloaded(content::BrowserContext* browser_context,
+                           const Extension* extension,
+                           UnloadedExtensionInfo::Reason reason) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ContentVerifier);
 
   friend class base::RefCountedThreadSafe<ContentVerifier>;
-  virtual ~ContentVerifier();
+  ~ContentVerifier() override;
 
   void OnFetchComplete(const std::string& extension_id,
                        bool success,