This is a class to manage large table updates from the server. Rather than
downloading the whole update and then updating the sqlite database, we
update tables as the data is streaming in.
Try to download updates from updateUrl. If an update is already in
progress, queues the requested update. This is used in nsIUrlListManager
as well as in testing.
| aRequestTables | Comma-separated list of tables included in this update. |
| aRequestBody | The body for the request. |
| aUpdateUrl | The plaintext url from which to request updates. |
| aSuccessCallback | Called after a successful update. |
| aUpdateErrorCallback | Called for problems applying the update |
| aDownloadErrorCallback | Called if we get an http error or a connection refused error. |