### 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.

### Electron Version

12.0.5

### What operating system are you using?

macOS

### Operating System Version

11.2.3

### What arch are you using?

arm64 (including Apple Silicon)

### Last Known Working Electron version

_No response_

### Expected Behavior

`document.hasFocus()` is only `true` for the window that has focus.

### Actual Behavior

Ever window reports `document.hasFocus()` to be `true` right after opening.

### Testcase Gist URL

https://gist.github.com/16e6fc829febd0cab115dfd0850a31be

### Additional Information

_No response_
shell/browser/api/electron_api_web_contents.cc
const gin_helper::Dictionary preferences) {
  v8::Isolate* isolate = JavascriptEnvironment::GetIsolate();
  v8::Locker locker(isolate);
  v8::HandleScope handle_scope(isolate);
  
  
  pending_child_web_preferences_.Reset(isolate, preferences.GetHandle());
}
content::WebConbContents::CreateCustomWebContents(
    content::RenderFrameHost* opener,
    content::SiteInstance* source_site_instance,
    bool is_new_browsing_instance,
    const GURL& opener_url,
    const std::string& frame_name,
    const GURL& target_url,
    const content::StoragePartitionId& partition_id,
    content::SessionStorageNamespace* session_storage_namespace) {
  return nullptr;
}
void WebContents::AddNewContents(