Hedger Wang 1caebf175a Add data structure to manage the stack for the legacy navigator.
Reviewed By: ericvicenti

Differential Revision: D3002015

fb-gh-sync-id: 27519a1b67fe514bd6d9102031ea482f76fae16b
shipit-source-id: 27519a1b67fe514bd6d9102031ea482f76fae16b
2016-03-03 22:52:51 -08:00
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2015-07-24 13:16:25 -08:00