[Fresh] Track mounted roots via DevTools Hook (#15928)

* Track mounted roots via DevTools Hook

* Add helper utilities to the runtime

These utilities will likely be needed by all module systems, so let's just put them here.

* Wrap more things in __DEV__

* Fix tests to also be DEV-only

Dan Abramov committed 6y ago

e9d0a3ff252ea72b1aa5e8df969304ff5c9aa0a4

Parent: 35ef78d

Committed by GitHub <noreply@github.com> on 6/19/2019, 11:12:43 PM