Summary:
Litho needs a new API which is called immediately before yoga begins layout calculations so that the InternalNode gets the opportunity to finalise itself; i.e. perform the last mutations and in effect avoid any more mutations to the hierarchy.
See D26373731 where the mutations from `Layout#collectResults` is moved back into the InternalNode.
Changelog: [Internal] Adds new API to YogaNodeJNIBase
Reviewed By: SidharthGuglani
Differential Revision: D26373730
fbshipit-source-id: 471346d3444986ada91e86c95f5f9fb98bcd2fa6
de36e85004