Summary:
## This diff: Add debugger mode infrastructure
We want to enable infrastructure allowing adding modes in the future without branching client and plugin code
This infra allows for the client to send a message informing flipper about the supported modes (following diffs)
Currently broadcasting mode change event over to the client
Reviewed By: lblasa
Differential Revision: D49385860
fbshipit-source-id: 2db6f65064d1ff7e1f57b2da93c3ed195400fb7f
Summary: The `visible` prop is marked as deprecated in favour of `open`
Reviewed By: passy
Differential Revision: D49226821
fbshipit-source-id: 4a4a7d03a1c8ff860c4e4cd02e19071185a8554e