### 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
v8::Local<v8::Value> input_event) {
  content::RenderWidgetHostView* view =
      ontents()->GetRenderWidgetHostView();
  if (!view)
    return;
  content::RenderWidgetHost* rwh = view->GetRenderWidgetHost();
  blink::WebInputEvent::Type type =
      gin::GetWebInputEventType(isolate, input_event);
  if (blink::WebInputEvent::IsMouseEventType(type)) {
    blink::WebMouseEvent mouse_event;
    if (gin::ConvertFromV8(isolate, input_event, &mouse_event)) {
      if (IsOffScreen()) {
#if BUILDFLAG(ENABLE_OSR)
        GetOffScreenRenderWidgetHostView()->SendMouseEvent(mouse_event);
#endif
      } else {
        rwh->ForwardMouseEvent(mouse_event);
      }
      return;
    }
  } else if (blink::WebInputEvent::IsKeyboardEventType(type)) {
    content::NativeWebKeyboardEvent keyboard_event(
        blink::WebKeyboardEvent::Type::kRawKeyDown,
        blink::WebInputEvent::Modifiers::kNoModifiers, ui::EventTimeForNow());
    if (gin::ConvertFromV8(isolate, input_event, &keyboard_event)) {
      rwh->ForwardKeyboardEvent(keyboard_event);
      return;
    }
  } else if (type == blink::WebInputEvent::Type::kMouseWheel) {