Background Fetch is about to start using the DownloadService. It does this through a delegate in //chrome, because //content cannot depend on the component directly. The relevant calls, notably DownloadUrl() and co., are exposed through the Content API.

As part of servicification, the DownloadService will be moving to //services and can thus be used by //content directly.

Once it has moved, we need to remove these APIs and use the //services interface directly. The BackgroundFetchDelegate will stay, but be focused entirely on the UI related functionality, delegating to the OfflineItemsCollection component.