zijiehe@

Close this roll as it's irrelevant anymore; the one with required gn-sdk change in dart will be rolled into flutter altogether with https://github.com/flutter/engine/pull/51072.

Thank you Alexander and Siva. I addressed all the comments and added autosubmit label since the tree is closing now. Let me know if you have other comments.

Sorry, I think this is a bug of github, I never touched this change :)