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

chrome/browser/content_settings/permission_context_base.h

Index: chrome/browser/content_settings/permission_context_base.h
diff --git a/chrome/browser/content_settings/permission_context_base.h b/chrome/browser/content_settings/permission_context_base.h
index 87b8afc62a8b3cef5ab0036aad37f53b409333ba..48fcac8ce7bca3fa842952276d509c09560959ab 100644
--- a/chrome/browser/content_settings/permission_context_base.h
+++ b/chrome/browser/content_settings/permission_context_base.h
@@ -52,7 +52,7 @@ class PermissionContextBase : public KeyedService {
  public:
   PermissionContextBase(Profile* profile,
                         const ContentSettingsType permission_type);
-  virtual ~PermissionContextBase();
+  ~PermissionContextBase() override;
 
   // The renderer is requesting permission to push messages.
   // When the answer to a permission request has been determined, |callback|