### 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& validated_url) {
  bool is_main_frame = !render_frame_host->GetParent();
  int frame_process_id = render_frame_host->GetProcess()->GetID();
  int frame_routing_id = render_frame_host->GetRoutingID();
  auto weak_this = GetWeakPtr();
  Emit("did-frame-finish-load", is_main_frame, frame_process_id,
       frame_routing_id);
   ⚠️WARNING!⚠️
   Emit() triggers JS which can call destroy() on |this|. It's not safe to
   assume that |this| points to valid memory at this point.
  if (is_main_frame && weak_this)
    Emit("did-finish-load");
}
void WebContents::DidFailLoad(content::RenderFrameHost* render_frame_host,
                              const GURL& url,
                              int error_code) {
  bool is_main_frame = !render_frame_host->GetParent();
  int frame_process_id = render_frame_host->GetProcess()->GetID();
  int frame_routing_id = render_frame_host->GetRoutingID();
  Emit("did-fail-load", error_code, "", url, is_main_frame, frame_process_id,
       frame_routing_id);
}
void WebContents::DidStartLoading() {
  Emit("did-start-loading");
}
void WebContents::DidStopLoading() {