fix: remove Electron BrowserWindow focus call

[rzhao271]

Description of Change

This change undoes #25292.

It removes the handler that focuses the BrowserWindow upon initial load. On Mac at least, it seems that Chromium handles the focusing just fine.

CC @deepak1556

Checklist

I'll work on finishing up these tasks later but I'll upload this PR for now for review.

• PR description included and stakeholders cc'd
• npm test passes
• see document.hasFocus() can return true for multiple windows being opened microsoft/vscode#122352 (comment) for what I've tested so far on the Mac.
• relevant documentation is changed or added
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: none.

[MarshallOfSound]

Can you confirm you've tested this change against the original fiddle reporting the issue?

https://gist.github.com/CharlieHess/c507468cd40630d04f58c6514100b997

[rzhao271]

I can confirm that that Fiddle continues to work even after the change.
I was expecting the grey unfocused border to show, but instead, as soon as I clicked the dock icon to pull up the window, I saw the border was yellow.
I tried recording a gif of it with gifcap.dev on Safari, but the webapp errored out.

I would like to test it manually on Windows later, too, and record gifs of my findings there.

concerns alleviated

[rzhao271]

Here's some recordings I made of the fix on Mac:

However, I noticed that webContents.getFocusedWebContents() returns false on Mac, unless I run it in a setTimeout(() => { ... }, 0); call.

On Windows, I'm not sure what the expected behaviour is.
When I set show: false, nothing seems to happen. I have to add in a setTimeout which calls win.show() to get the window to show up. On Mac, I just need to click on the Electron icon in the dock.
When I set show: true and run a variation of Ben's fiddle (https://gist.github.com/rzhao271/65a35a76c4c200ee04adb82d2765555a), none of the windows are initially focused (see below). I'm not sure if this is the expected behaviour on Windows.

[rzhao271]

An example showing how the original Fiddle behaviour is still as expected (yellow frame showing up = good, grey frame showing up = bad):

An example showing how @bpasero's Fiddle now accurately reports which window is focused on a Mac (only the top-most window's devtools shows true as the first line, the other ones show false):

However, all of the windows now claim to be unfocused on Windows during startup:

Additionally, webContents.getFocusedWebContents() now returns false unless it's run inside of a setTimeout. I think this occurs due to Electron not picking up the fact that Chromium is now responsible for focusing the webContents. I believe @deepak1556 is looking into this case.

[deepak1556]

I am unable to push changes to this PR, closing in favor of #29204