Summary: X-link: https://github.com/facebook/react-native/pull/46800 Pull Request resolved: https://github.com/facebook/yoga/pull/1716 Had a mini heart attack thinking I set the default to content box. Wrote this to double check and it passed. Might as well check it in Technically the default to BoxSizing.h is ContentBox, but in the style we override that. Regardless I switched that around so border box was the default. Changelog: [Internal] Reviewed By: NickGerleman Differential Revision: D63802722 fbshipit-source-id: 49ed29657c964bc12a2bf70988061ab4599267ec