### 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
blink::CloneableMessage arguments) {
  TRACE_EVENT1("electron", "WebContents::MessageHost", "channel", channel);
   webContents.emit('ipc-message-host', new Event(), channel, args);
  EmitWithSender("ipc-message-host", receivers_.current_context(),
                 InvokeCallback(), channel, std::move(arguments));
}
void WebContents::UpdateDraggableRegions(
    std::vector<mojom::DraggableRegionPtr> regions) {
  for (ExtendedWebContentsObserver& observer : observers_)
    observer.OnDraggableRegionsUpdated(regions);
}
void WebContents::RenderFrameDeleted(
    content::RenderFrameHost* render_frame_host) {
   A RenderFrameHost can be destroyed before the related Mojo binding is
   closed, which can result in Mojo calls being sent for RenderFrameHosts
   that no longer exist. To prevent this from happening, when a
   RenderFrameHost goes away, we close all the bindings related to that
   frame.
  auto it = frame_to_receivers_map_.find(render_frame_host);
  if (it == frame_to_receivers_map_.end())
    return;
  for (auto id : it->second)
    receivers_.Remove(id);
  frame_to_receivers_map_.erase(it);
}
void WebContents::DidStartNavigation(