### 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](https://www.github.com/electron/electron/issues) for a feature request that matches the one I want to file, without success.

### Electron Version

14.0.0-beta.12

### What operating system are you using?

Windows

### Operating System Version

10.0.19042 Build 19042

### What arch are you using?

x64

### Last Known Working Electron version

13

### Expected Behavior

Window should be transparent

### Actual Behavior

Open a window with transparency enabled and delete the dom, the window will be white instead of transparent.
**Also seems like settings the backgroundColor property has no longer an effect.** I always see a white window

```
const {app, BrowserWindow} = require('electron')
const path = require("path");

function createWindow () {
	const mainWindow = new BrowserWindow({
		transparent: true,
		frame: false,
	})

	mainWindow.loadURL('https://example.com')
	mainWindow.webContents.openDevTools()
}

app.whenReady().then(createWindow)
```

### Testcase Gist URL

https://gist.github.com/e124340107f6c4a3ade8b36d98a16b9a

### Additional Information

_No response_
shell/browser/api/electron_api_web_contents.cc
gin::HContents> WebContents::New(
    v8::Isolate* isolate,
    const gin_helper::Dictionary& options) {
  gin::HContents> handle =
      gin::CreateHandle(isolate, new WebContents(isolate, options));
  v8::TryCatch try_catch(isolate);
  gin_helper::CallMethod(isolate, handle.get(), "_init");
  if (try_catch.HasCaught()) {
    node::errors::TriggerUncaughtException(isolate, try_catch);
  }
  return handle;
}
 static
gin::HContents> WebContents::CreateAndTake(
    v8::Isolate* isolate,
    std::unique_ptr<content::WebContents> ontents,
    Type type) {
  gin::HContents> handle = gin::CreateHandle(
      isolate, new WebContents(isolate, std::move(ontents), type));
  v8::TryCatch try_catch(isolate);
  gin_helper::CallMethod(isolate, handle.get(), "_init");
  if (try_catch.HasCaught()) {
    node::errors::TriggerUncaughtException(isolate, try_catch);
  }
  return handle;
}
 static