Merge from Widevine repo of http://go/wvgerrit/75123
Merge from Widevine repo of http://go/wvgerrit/75114
This changes the encoding for the hash to be hex instead of base64.
Also, the bad frame number is initialized to 0 to make it easier to
debug. And the FDPT test app now uses the correct byte order.
Bug: 129100318
Test: unit tests, FDPT test app.
Change-Id: I296bab990125a4e18bec92f3316e8289a3b25a6b