More specifically, this CL
- Defines a VideoGraph interface
- Adds a factory method, to hide the constructors
- Separate out an initialize method that does the real work (following that constructor should not do real work)
- The VideoGraph takes in a list of composition effects. For now, we only use the `Presentation`, if there is one in the list. This means we can take any number of Presentations now, but only the first one will be used.
- Moves the VideoFrameProcessingWrapper to its own file
PiperOrigin-RevId: 561059653
b466b06ace