Summary:
Fixes the sizing of items so that under most scenarios it calcultes its height by it's content for non exact measurings. This introduces a new useLegacyStretchBehaviour flag on the config to opt out of this change as it is breaking.
See facebook/yoga#505
Closes https://github.com/facebook/yoga/pull/506
Reviewed By: astreet
Differential Revision: D4954016
Pulled By: emilsjolander
fbshipit-source-id: d28bd5d174cd76951fb94df85e3b0cfab7f81ff7
203577724e