[ Merge of http://go/wvgerrit/23600 ]
This adds a new entry to IStorage:: -
bool list(std::vector<std::string> file_names)
It returns the name of each file in the (origin-specific) file system.
b/34628115
Uses the current file system (origin-specific) bound to the CDM. Returns
the list of stored licenses (key_set_ids) in vector output parameter.
Test: verified by unittests on angler.
Change-Id: I988556b27c2a4b75f52b59bcd78cfeaddd649acd
6d617e2be4