Summary:
`RCTBaseEvent` was never used. This diff removes it.
public
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//This diff is part of a larger stack. For high level overview what's going on jump to D2884593.//
Reviewed By: javache
Differential Revision: D2884585
fb-gh-sync-id: 66a6afcda3b5baec7f768682da215570f6d33bb1