### 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
const std::string& name) {
  base::FilePath path;
  int key = GetPathConstant(name);
  if (key < 0 || !base::PathService::Get(key, &path))
    thrower.ThrowError("Failed to get '" + name + "' path");
  return path;
}
void App::SetPath(gin_helper::ErrorThrower thrower,
                  const std::string& name,
                  const base::FilePath& path) {
  if (!path.IsAbsolute()) {
    thrower.ThrowError("Path must be absolute");
    return;
  }
  int key = GetPathConstant(name);
  if (key < 0 || !base::PathService::OverrideAndCreateIfNeeded(
                     key, path,  true,  false))
    thrower.ThrowError("Failed to set path");
}
void App::SetDesktopName(const std::string& desktop_name) {