Summary: Added default constructor for YGCachedMeasurement. This diff uses the default initialiser to get rid off the older designated initializer syntax. This diff also addresses https://github.com/facebook/yoga/pull/700 Reviewed By: emilsjolander Differential Revision: D7020337 fbshipit-source-id: e084e234bf6a2ae22e53e739959683abca169b88