Summary: As I've begun to integrate this into the codebase, I've found that sometimes our layouts are affected by bad implementations of sizeThatFits:. For example, in certain configurations of UILabel it won't take clipping into account and return a size that is much larger than the max size we requested. This adds some checks to make sure we never return a size that is larger than the one specified by `_measure`. This also fixes the bug where `CSSMeasureModeExactly` won't be applied if the measure mode for other parameter is node `CSSMeasureModeExactly`.
Reviewed By: emilsjolander
Differential Revision: D4131195
fbshipit-source-id: 4659fd83892a2c149b3b70733b06b19217507bf9
1ffce3edb1