
`WebvttDecoder` which used to be `SimpleSubtitleDecoder` will now be called `WebvttParser` and implement `SubtitleParser` interface. For backwards compatibility, we will have the same functionality provided by `DelegatingSubtitleDecoder` backed-up by a new `WebvttParser` instance. `WebvttSubtitle` will still be used behind the scenes to handle overlapping `Cues`. PiperOrigin-RevId: 549298733