media/libraries
ibaker 913f6da083 MCR: Ensure mediaCrypto and codec are atomically non-null
`mediaCrypto` is initialized before `codec` in
`maybeInitCodecOrBypass`. Before this change, it was possible for
`maybeInitCodecOrBypass` to complete with `mediaCrypto != null` and
`codec == null`, in particular if it was run as part of clearing the
player surface (since in that case, no video codec is initialized).
This inconsistent state then causes issues during a later invocation of
`maybeInitCodecOrBypass`, when `mediaCrypto` is still non-null, and
`mediaCryptoRequiresSecureDecoder = true`, but the
content has been changed to unencrypted with no associated DRM session.
This results in a playback error, because a secure decoder is
initialized but there's no DRM session available to work with it.

This change ensures that when `maybeInitCodecOrBypass` completes,
either both `mediaCrypto != null` and `codec != null` (i.e. codec
initialization was completed) or `mediaCrypto == null` and
`codec == null` (i.e. codec initialization was not completed). We also
ensure that when nulling out `mediaCrypto` we also set
`maybeInitCodecOrBypass = false`. A later change should be able to
demote `maybeInitCodecOrBypass` from a field to a local in order to
remove any risk of that part of state becoming out of sync. This
resolves the issue, because during the second invocation of
`maybeInitCodecOrBypass` an insecure decoder is now (correctly)
initialized and the unencrypted content is successfully played.

#minor-release

PiperOrigin-RevId: 587713911
2023-12-04 07:32:52 -08:00
..
2023-11-27 10:02:02 -08:00