Summary:
- Define CSS_ASSERT_FAIL_ENABLED for P/Invoke (Visual Studio project already has it)
- Pass managed delegate pointer to unmanaged side via P/Invoke.
- CSSAssertFail will call the managed delegate when assert failed.
- The delegate will throw managed exception.
Reviewed By: emilsjolander
Differential Revision: D3982084
fbshipit-source-id: 058a87c10ca89238362be4d8759cc00dd0c9b376
