694d040d7e
This change uses the new incremental overloads of `SubtitleParser` to avoid introducing the performance regression caused by the original change requiring all cues to be fully parsed before the first could be shown on screen. `TtmlDecoder` which used to be `SimpleSubtitleDecoder` will now be called `TtmlParser` and implement `SubtitleParser` interface. For backwards compatibility, we will have the same functionality provided by `DelegatingSubtitleDecoder` backed-up by a new `TtmlParser` instance. PiperOrigin-RevId: 566671398