Summary:
Scheduler and JavaUIManager mutexes share the lifetime (between install-uninstall), so we can use singular shared lock to ensure that both sections are locked exclusively for install/uninstall and in shared mode for access.
Changelog: [Internal]
Reviewed By: mdvacca
Differential Revision: D33130686
fbshipit-source-id: bf283fd5410e386d2635645e17680a9f4cb7f288