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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
#endif
#if defined(OS_LINUX)
#include "ui/views/linux_ui/linux_ui.h"
#endif
#if defined(OS_LINUX) || defined(OS_WIN)
#include "ui/gfx/font_render_params.h"
#endif
#if BUILDFLAG(ENABLE_ELECTRON_EXTENSIONS)
#include "extensions/browser/script_executor.h"
#include "shell/browser/extensions/electron_extension_ontents_observer.h"
#endif
namespace gin {
#if BUILDFLAG(ENABLE_PRINTING)
template <>
struct Converter<printing::PrinterBasicInfo> {
  static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
                                   const printing::PrinterBasicInfo& val) {
    gin_helper::Dictionary dict = gin::Dictionary::CreateEmpty(isolate);
    dict.Set("name", val.printer_name);
    dict.Set("displayName", val.display_name);
    dict.Set("description", val.printer_description);
    dict.Set("status", val.printer_status);
    dict.Set("isDefault", val.is_default ? true : false);
    dict.Set("options", val.options);
    return dict.GetHandle();
  }
};
template <>
struct Converter<printing::MarginType> {
  static bool FromV8(v8::Isolate* isolate,