Valentin Shergin ef6b916e48 Fabric: New approach to manage Yoga's parent/owner references
Summary:
The modern Concurent Yoga's concept is:
We have to set parent/owner reference as part of `appendChild` process only if the current reference to parent/owner is `null`.
The motivation:
 * Null-parent indicates that this node was not attached to anything yet;
 * So, in this case there is no any concurrent memory access because we always create and (first time) attach the node on same thread;
 * Simmetrical parent-child relationship indicates that we don't need to (re)clone assosiated ShadowNode (nor Yoga node).

Reviewed By: mdvacca

Differential Revision: D7467791

fbshipit-source-id: 9a7f517380fde3bb00272de18fd5dc13edb52071
2018-04-10 12:59:51 -07:00
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2018-03-18 19:17:39 -07:00
2018-03-18 19:17:39 -07:00