Since #19488, the network service is enabled and the old path has been deleted. Some features are broken as a result and will need to be fixed before 8.0.0. This is a tracking issue for those features.

- [x] webRequest API (zcbenz)
- [x] service workers on file protocol (#20132)
- [x] session.clearAuthCache - tests (#20015)
- [x] session.getBlobData (#20041)
- [x] session.setUserAgent (#20014)
- [x] custom standard schemes / registerSchemesAsPrivileged
- [x] Rewire Login Handler from NetworkDelegate into ProxyingURLLoaderFactory
- [x] fix 'login' event not firing on net requests

cc @deepak1556 @jkleinsc @zcbenz 
shell/browser/api/atom_api_session.cc
: network_emulation_token_(base::UnguessableToken::Create()),
      browser_context_(browser_context) {
  
  content::BrowserContext::GetDownloadManager(browser_context)
      ->AddObserver(this);
  new SessionPreferences(browser_context);
  Init(isolate);
  AttachAsUserData(browser_context);
}
Session::~Session() {
  content::BrowserContext::GetDownloadManager(browser_context())
      ->RemoveObserver(this);
  
  
  
  DestroyGlobalHandle(isolate(), cookies_);
  DestroyGlobalHandle(isolate(), protocol_);
  DestroyGlobalHandle(isolate(), net_log_);
  g_sessions.erase(weak_map_id());
}
void Session::OnDownloadCreated(content::DownloadManager* manager,