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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
Emit("devtools-reload-page");
}
void Ws::DevToolsFocused() {
  Emit("devtools-focused");
}
void Ws::DevToolsOpened() {
  v8::Locker locker(isolate());
  v8::HandleScope handle_scope(isolate());
  auto handle =
      FromOrCreate(isolate(), managed_ontents()->GetDevToolsWs());
  devtools_ontents_.Reset(isolate(), handle.ToV8());
   Set inspected tabID.
  base::Value tab_id(ID());
  managed_ontents()->CallClientFunction("DevToolsAPI.setInspectedTabId",
                                             &tab_id, nullptr, nullptr);
   Inherit owner window in devtools when it doesn't have one.
  auto* devtools = managed_ontents()->GetDevToolsWs();
  bool has_window = devtools->GetUserData(NativeWindowRelay::UserDataKey());
  if (owner_window() && !has_window)
    handle->SetOwnerWindow(devtools, owner_window());
  Emit("devtools-opened");
}
void Ws::DevToolsClosed() {
  v8::Locker locker(isolate());
  v8::HandleScope handle_scope(isolate());
  devtools_ontents_.Reset();
  Emit("devtools-closed");
}
bool Ws::OnMessageReceived(const IPC::Message& message) {
  bool handled = true;