The DPDocDomPPF is a ProviderPackageFile which handles the display
profile documents in the par file. It is different from the
ParEntryDomPPF based on the usage of the par file. This is to
support the backup/restore archive where the dp entry is not served
as the entry name, in fact, there will be more then one dp
documents inside one entry in the manifest file. The getDPZip() method
in ParManifest.java has the assumption of only one dp
in a par entry, where as in the backup/restore archive there could
be more then one.