### 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.h
void UpdateTargetURL(content::WebContents* source, const GURL& url) override;
  bool HandleKeyboardEvent(
      content::WebContents* source,
      const content::NativeWebKeyboardEvent& event) override;
  content::KeyboardEventProcessingResult PreHandleKeyboardEvent(
      content::WebContents* source,
      const content::NativeWebKeyboardEvent& event) override;
  void ContentsZoomChange(bool zoom_in) override;
  void EnterFullscreenModeForTab(
      content::RenderFrameHost* requesting_frame,
      const blink::mojom::FullscreenOptions& options) override;
  void ExitFullscreenModeForTab(content::WebContents* source) override;
  void RendererUnresponsive(
      content::WebContents* source,
      content::RenderWidgetHost* render_widget_host,
      base::RepeatingClosure hang_monitor_restarter) override;
  void RendererResponsive(
      content::WebContents* source,
      content::RenderWidgetHost* render_widget_host) override;
  bool HandleContextMenu(content::RenderFrameHost* render_frame_host,
                         const content::ContextMenuParams& params) override;
  bool OnGoToEntryOffset(int offset) override;
  void FindReply(content::WebContents* web_contents,
                 int request_id,
                 int number_of_matches,
                 const gfx::Rect& selection_rect,
                 int active_match_ordinal,
                 bool final_update) override;
  bool CheckMediaAccessPermission(content::RenderFrameHost* render_frame_host,
                                  const GURL& security_origin,