Summary: Our extensions dependecies are getting tricky. Let's make it right. (the logic still need to be tested - it worked on one very simple example so far).
Test Plan: no tests yet
Reviewers: pyd, lcharignon, rmcelroy
Reviewed By: rmcelroy
Subscribers: lcharignon, #sourcecontrol
Differential Revision: https://phabricator.fb.com/D2710943
Signature: t1:2710943:1449881799:16abe49529aa79df7d6ebe84a0bae0c0970b419a