### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
- [X] I have searched the [issue tracker](https://www.github.com/electron/electron/issues) for a feature request that matches the one I want to file, without success.

### Problem Description

We need to load a custom error page when the certificate is invalid but without "isMainFrame" property we don't know when to load the custom error page using webContents.loadURL()

### Proposed Solution

webContents.on("certificate-error", ((event, url, error, certificate, callback, isMainFrame)

### Alternatives Considered

Not sure

### Additional Information

Not sure
shell/browser/api/electron_api_app.cc
if (size == "small") {
    return IconLoader::IconSize::SMALL;
  } else if (size == "large") {
    return IconLoader::IconSize::LARGE;
  }
  return IconLoader::IconSize::NORMAL;
}
int GetPathConstant(const std::string& name) {
  if (name == "appData")
    return DIR_APP_DATA;
  else if (name == "userData")
    return chrome::DIR_USER_DATA;
  else if (name == "cache")
#if defined(OS_POSIX)
    return base::DIR_CACHE;
#else
    return base::DIR_APP_DATA;
#endif
  else if (name == "userCache")
    return DIR_USER_CACHE;
  else if (name == "logs")
    return DIR_APP_LOGS;