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
const base::FilePath& path,
                        const std::vector<GURL>& url_chain,
                        const std::string& mime_type,
                        int64_t offset,
                        int64_t length,
                        const std::string& last_modified,
                        const std::string& etag,
                        const base::Time& start_time,
                        uint32_t id) {
  download_manager->CreateDownloadItem(
      base::GenerateGUID(), id, path, path, url_chain, GURL(), GURL(), GURL(),
      GURL(), base::nullopt, mime_type, mime_type, start_time, base::Time(),
      etag, last_modified, offset, length, std::string(),
      download::DownloadItem::INTERRUPTED,
      download::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
      download::DOWNLOAD_INTERRUPT_REASON_NETWORK_TIMEOUT, false, base::Time(),
      false, std::vector<download::DownloadItem::ReceivedSlice>());
}
void DestroyGlobalHandle(v8::Isolate* isolate,