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OnBackPressedDispatcherOwner A class that has an OnBackPressedDispatcher that allows you to register a OnBackPressedCallback for handling the system back button. 


ComponentActivity Base class for activities that enables composition of higher level components. 
OnBackPressedCallback Class for handling OnBackPressedDispatcher.onBackPressed() callbacks without strongly coupling that implementation to a subclass of ComponentActivity
OnBackPressedDispatcher Dispatcher that can be used to register OnBackPressedCallback instances for handling the ComponentActivity.onBackPressed() callback via composition.