YARN-5959 introduced an ContainerUpdateContext which can be used to update the ExecutionType of a container in a scheduler agnostic manner. As mentioned in that JIRA, extending that to encompass Container resizing is trivial.
This JIRA proposes to remove all the CapacityScheduler specific code paths. (CapacityScheduler, CSQueue, FicaSchedulerApp etc.) and modify the code to use the framework introduced in
YARN-5959 without any loss of functionality.