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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
CommonWsDelegate::ExitFullscreenModeForTab(source);
  Emit("leave-html-full-screen");
}
void Ws::RendererUnresponsive(
    content::Ws* source,
    content::RenderWidgetHost* render_widget_host,
    base::RepeatingClosure hang_monitor_restarter) {
  Emit("unresponsive");
}
void Ws::RendererResponsive(
    content::Ws* source,
    content::RenderWidgetHost* render_widget_host) {
  Emit("responsive");
}
bool Ws::HandleContextMenu(content::RenderFrameHost* render_frame_host,
                                    const content::ContextMenuParams& params) {
  if (params.custom_context.is_pepper_menu) {
    Emit("pepper-context-menu", std::make_pair(params, ontents()),
         base::BindOnce(&content::Ws::NotifyContextMenuClosed,
                        base::Unretained(ontents()),
                        params.custom_context));
  } else {
    Emit("context-menu", std::make_pair(params, ontents()));
  }
  return true;
}
bool Ws::OnGoToEntryOffset(int offset) {