[Bug]: Electron 16.0.5 cannot enable webviewTag in nativeWindowOpen sub window

[KochiyaOcean]

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Electron Version

16.0.5

What operating system are you using?

Windows

Operating System Version

10 version 19043

What arch are you using?

x64

Last Known Working Electron version

16.0.4

Expected Behavior

When a sub window opened with webviewTag set to true, the webview in sub window should works correctly

Actual Behavior

In the subwindow, the webviewTag option is not actually enabled and webview is not working

Testcase Gist URL

https://gist.github.com/72a8040c33a7deeebdfe88d409d8ca0b

Additional Information

In the testcase, type following command in devtool console and press enter:

w = open('./index.html')
setTimeout(() => {
    w.document.querySelector('webview').addEventListener('dom-ready', (e) => console.log(e))
    w.document.querySelector('webview').reload()
}, 100)

The console will open a subwindow, but in the subwindow the webview did not load, and the console throws error w.document.querySelector(...).reload is not a function

[KochiyaOcean]

I think it should be related to #32057

17.0.0-beta.5 has the same issue, which also includes this change (17.0.0-beta.4 do not include the change so it does not have such issue)

[codebytere]

cc @miniak @zcbenz

[zcbenz]

The previous behavior was actually a security bug, the new-window event does not have the ability to override the webPreferences, it only reuses the WebContents created by Chromium, so the passed webPreferences is actually ignored. The code used to work because the child window inherited the webviewTag: true from parent window directly, which was a bug instead of expected behavior.

The correct way to do it is to use webContents.setWindowOpenHandler API instead:

  mainWindow.webContents.setWindowOpenHandler(() => {
    return {
      action: 'allow',
      overrideBrowserWindowOptions: {
        webPreferences: {
          webviewTag: true
        }   
      }   
    }   
  });