### 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 feature request that matches the one I want to file, without success.

### Electron Version

14.0.1

### What operating system are you using?

macOS

### Operating System Version

macOS Big Sur 11.6.1

### What arch are you using?

x64

### Last Known Working Electron version

14.0.0

### Expected Behavior


When `BrowserView.setBackgroundColor` is called with an explicit color, expect the background to be the color selected.

When `BrowserView.setBackgroundColor` is not called, expect the background of the `BrowserView` to be transparent by default; and can see through `BrowserWindow`'s background color.



### Actual Behavior

The `BrowserView` background is always white.

### Testcase Gist URL

https://gist.github.com/kevinlinv/2de60478ffec6a2f18f1ec0fc6f5add9

### Additional Information

Here is a quick recording that reproduces the error.

https://user-images.githubusercontent.com/44967897/140694174-e27aff28-1847-4813-bc46-d9fda6569128.mp4


shell/browser/api/electron_api_web_contents.cc
} else {
    settings.SetBoolKey(printing::kSettingHeaderFooterEnabled, false);
  }
   We don't want to allow the user to enable these settings
   but we need to set them or a CHECK is hit.
  settings.SetIntKey(printing::kSettingPrinterType,
                     static_cast<int>(printing::mojom::PrinterType::kLocal));
  settings.SetBoolKey(printing::kSettingShouldPrintSelectionOnly, false);
  settings.SetBoolKey(printing::kSettingRasterizePdf, false);
   Set custom page ranges to print
  std::vector<gin_helper::Dictionary> page_ranges;
  if (options.Get("pageRanges", &page_ranges)) {
    base::Value page_range_list(base::Value::Type::LIST);
    for (auto& range : page_ranges) {
      int from, to;
      if (range.Get("from", &from) && range.Get("to", &to)) {
        base::Value range(base::Value::Type::DICTIONARY);
         Chromium uses 1-based page ranges, so increment each by 1.
        range.SetIntKey(printing::kSettingPageRangeFrom, from + 1);
        range.SetIntKey(printing::kSettingPageRangeTo, to + 1);
        page_range_list.Append(std::move(range));
      } else {
        continue;
      }
    }
    if (!page_range_list.GetList().empty())
      settings.SetPath(printing::kSettingPageRange, std::move(page_range_list));
  }
   Duplex type user wants to use.
  printing::mojom::DuplexMode duplex_mode =