### 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
if (success) {
              promise.Resolve();
            } else {
              promise.RejectWithErrorMessage("takeHeapSnapshot failed");
            }
          },
          base::Owned(std::move(electron_renderer)), std::move(promise)));
  return handle;
}
 static
v8::LobjectTemplate> WebContents::FillObjectTemplate(
    v8::Isolate* isolate,
    v8::LobjectTemplate> templ) {
  gin::InvokerOptions options;
  options.holder_is_first_argument = true;
  options.holder_type = "WebContents";
  templ->Set(
      gin::StringToSymbol(isolate, "isDestroyed"),
      gin::CreateFunctionTemplate(
          isolate, base::BindRepeating(&gin_helper::Destroyable::IsDestroyed),
          options));
  templ->Set(
      gin::StringToSymbol(isolate, "destroy"),
      gin::CreateFunctionTemplate(
          isolate, base::BindRepeating([](gin::HContents> handle) {
            delete handle.get();
          }),
          options));
   We use gin_helper::ObjectTemplateBuilder instead of
   gin::ObjectTemplateBuilder here to handle the fact that WebContents is