### 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
bool send_to_all,
                                        int32_t frame_id,
                                        const std::string& channel,
                                        v8::Local<v8::Value> args) {
  v8::Isolate* isolate = JavascriptEnvironment::GetIsolate();
  blink::CloneableMessage message;
  if (!gin::ConvertFromV8(isolate, args, &message)) {
    isolate->ThrowException(v8::Exception::Error(
        gin::StringToV8(isolate, "Failed to serialize arguments")));
    return false;
  }
  auto frames = ontents()->GetAllFrames();
  auto iter = std::find_if(frames.begin(), frames.end(), [frame_id](auto* f) {
    return f->GetRoutingID() == frame_id;
  });
  if (iter == frames.end())
    return false;
  if (!(*iter)->IsRenderFrameLive())
    return false;
  mojo::AssociatedRemote<mojom::ElectronRenderer> electron_renderer;
  (*iter)->GetRemoteAssociatedInterfaces()->GetInterface(&electron_renderer);
  electron_renderer->Message(internal, send_to_all, channel, std::move(message),
                             0 /* sender_id */);
  return true;
}
void WebContents::SendInputEvent(v8::Isolate* isolate,