### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/main/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/main/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 bug report that matches the one I want to file, without success.

### Electron Version

17.0.0

### What operating system are you using?

Windows

### Operating System Version

Windows 10 Version 21H1

### What arch are you using?

x64

### Last Known Working Electron version

14.2.3

### Expected Behavior

background should transparent if background is #00000000

### Actual Behavior

has a white background

### Testcase Gist URL

_No response_

### Additional Information

_No response_
shell/browser/api/electron_api_web_contents.cc
#if !BUILDFLAG(IS_WIN)
  static constexpr base::TaskTraits kTraits = {
      base::MayBlock(), base::TaskPriority::USER_VISIBLE};
#endif
#if defined(USE_CUPS)
  
  return base::ThreadPool::CreateTaskRunner(kTraits);
#elif BUILDFLAG(IS_WIN)
  
  
  return content::GetUIThreadTaskRunner(
      {base::MayBlock(), base::TaskPriority::USER_VISIBLE});
#else
  
  return base::ThreadPool::CreateSingleThreadTaskRunner(kTraits);
#endif
}
#endif
struct UserDataLink : public base::SupportsUserData::Data {
  explicit UserDataLink(base::WeakPtr<WebContents> contents)