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Ref #19447

### Issue Details

* **Electron Version:**
  * 9.0.0-beta.24
* **Operating System:**
  * macOS 10.15, Windows 10
* **Last Known Working Electron version:**
  * none

### Expected Behavior
`e.sender` object received from an extension background page should have `webPreferences` and `session` initialized. It looks like `options` in `api::WebContents` constructor don't get initialized properly for an extension background page.

### Actual Behavior
`e.sender` object doesn't have `session` and `e.sender.getWebPreferences()` returns `null`.

### To Reproduce
https://github.com/sentialx/electron-quick-start/tree/extensions/no-session

Just run it and you will see something like this:
![image](https://user-images.githubusercontent.com/11065386/82097607-82994400-9703-11ea-8291-0eb987d8aca0.png)

### Additional Information
This is a real blocker for anyone who would want to provide own `chrome` APIs in background pages initialized from different sessions.
shell/browser/api/electron_api_web_contents.cc
settings.SetKey(printing::kSettingMediaSize, std::move(media_size));
   Set custom dots per inch (dpi)
  gin_helper::Dictionary dpi_settings;
  int dpi = 72;
  if (options.Get("dpi", &dpi_settings)) {
    int horizontal = 72;
    dpi_settings.Get("horizontal", &horizontal);
    settings.SetIntKey(printing::kSettingDpiHorizontal, horizontal);
    int vertical = 72;
    dpi_settings.Get("vertical", &vertical);
    settings.SetIntKey(printing::kSettingDpiVertical, vertical);
  } else {
    settings.SetIntKey(printing::kSettingDpiHorizontal, dpi);
    settings.SetIntKey(printing::kSettingDpiVertical, dpi);
  }
  base::ThreadPool::PostTaskAndReplyWithResult(
      FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_BLOCKING},
      base::BindOnce(&GetDefaultPrinterAsync),
      base::BindOnce(&Ws::OnGetDefaultPrinter,
                     weak_factory_.GetWeakPtr(), std::move(settings),
                     std::move(callback), device_name, silent));
}
std::vector<printing::PrinterBasicInfo> Ws::GetPrinterList() {
  std::vector<printing::PrinterBasicInfo> printers;
  auto print_backend = printing::PrintBackend::CreateInstance(
      nullptr, g_browser_process->GetApplicationLocale());
  {
     TODO(deepak1556): Deprecate this api in favor of an
     async version and post a non blocing task call.
    base::ThreadRestrictions::ScopedAllowIO allow_io;