We have some very long parameter lists in ui_dart_state.h dart_isolate.h, runtime_controller.h, and engine.h that basically just get forwarded around from Shell to engine to runtime controller to dart isolate to dart state.

Every time we update this list, it gets more unweidly and a bunch of unrelated tests have to get updated. It should be pretty straightforward to refactor this so that it uses a common object to encapsulate these state items, which could allow for sensible defaults for tests and avoid lots of long parameter lists.

Low priority since we don't add these often and this is just about internal code health.

/cc @jason-simmons @chinmaygarde fyi