### 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
.SetMethod("setAppUserModelId",
                 base::BindRepeating(&Browser::SetAppUserModelID, browser))
#endif
      .SetMethod(
          "isDefaultProtocolClient",
          base::BindRepeating(&Browser::IsDefaultProtocolClient, browser))
      .SetMethod(
          "setAsDefaultProtocolClient",
          base::BindRepeating(&Browser::SetAsDefaultProtocolClient, browser))
      .SetMethod(
          "removeAsDefaultProtocolClient",
          base::BindRepeating(&Browser::RemoveAsDefaultProtocolClient, browser))
#if !defined(OS_LINUX)
      .SetMethod(
          "getApplicationInfoForProtocol",
          base::BindRepeating(&Browser::GetApplicationInfoForProtocol, browser))
#endif
      .SetMethod(
          "getApplicationNameForProtocol",
          base::BindRepeating(&Browser::GetApplicationNameForProtocol, browser))
      .SetMethod("setBadgeCount",
                 base::BindRepeating(&Browser::SetBadgeCount, browser))
      .SetMethod("getBadgeCount",
                 base::BindRepeating(&Browser::GetBadgeCount, browser))
      .SetMethod("getLoginItemSettings", &App::GetLoginItemSettings)
      .SetMethod("setLoginItemSettings",
                 base::BindRepeating(&Browser::SetLoginItemSettings, browser))
      .SetMethod("isEmojiPanelSupported",
                 base::BindRepeating(&Browser::IsEmojiPanelSupported, browser))
#if defined(OS_MAC)