### 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 for an issue that matches the one I want to file, without success.

### Issue Details

* **Electron Version:**
  * 10.1.1
* **Operating System:**
  * macOS 10.15.4

We recently started launching as hidden on macOS (that is, `show: false` or `browserWindow.hide()` while loading the page, followed by `browserWindow.show()` when the dock icon is clicked). This results in some busted focus behavior on the first activation of the window. The second activation restores it.

### Expected Behavior
The guest page receives a `focus` event on the first activation of the app, when created with `show: false`.

### Actual Behavior
The guest page doesn't receive the first `focus` event. Subsequent activations do trigger a `focus` event.

### To Reproduce
[Electron Fiddle](https://gist.github.com/CharlieHess/c507468cd40630d04f58c6514100b997)

shell/browser/api/electron_api_web_contents.cc
const GURL& target_url,
    const content::Referrer& referrer,
    const std::string& frame_name,
    WindowOpenDisposition disposition,
    const std::string& features,
    const scoped_refptr<network::ResourceRequestBody>& body) {
  Emit("-new-window", target_url, frame_name, disposition, features, referrer,
       body);
}
void WebContents::WebContentsCreatedWithFullParams(
    content::WebContents* source_contents,
    int opener_render_process_id,
    int opener_render_frame_id,
    const content::mojom::CreateNewWindowParams& params,
    content::WebContents* new_contents) {
  ChildWebContentsTracker::CreateForWebContents(new_contents);
  auto* tracker = ChildWebContentsTracker::FromWebContents(new_contents);
  tracker->url = params.target_url;
  tracker->frame_name = params.frame_name;
  tracker->referrer = params.referrer.To<content::Referrer>();
  tracker->raw_features = params.raw_features;
  tracker->body = params.body;
}
bool WebContents::IsWebContentsCreationOverridden(