*** Original commit ***
Move SimpleExoPlayer logic into ExoPlayerImpl
This makes SimpleExoPlayer a simple forwarding wrapper which can be
removed in the future.
The changes are all purely mechanical with none of the potential further
simplifications made yet. The only exceptions are name clashes where
either EPI or SEP was calling a method in one of the classes and both
classes had different implementations for the same method name. In these
cases we needed to disambiguate between the two different
implementations (e
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PiperOrigin-RevId: 426997821
fab5dfa156