The join mode is used for two cases: surface switching and mid-playback
enabling of video.
In both cases, we want to pretend to be ready despite not having rendered
a new "first frame". So far, we also avoided force-rendering the first
frame immediately because it causes a stuttering effect for the
mid-playback enable case. The surface switch case doesn't have this
stuttering issue as the same codec is used without interruption. Not
force-rendering the frame immediately causes the first-frame rendered
callback to arrive too early though, which may lead to cases where
apps hide shutter views too quickly.
This problem can be solved by only avoiding the force-render for the
mid-playback enabling case, but not for the surface switching case.
PiperOrigin-RevId: 622105916
e0fa697edf