These changes seem like ones that the Chromium team would have already considered and opted out of. ultimately they need to support their product and the debug features are for that purpose. Not picking max optimization helps avoid toolchain bugs. Using "-mllvm" flags from clang is asking for trouble.

That said, good for them. It's an achievement and if they can support their browser well, then it's the perfect reason for a fork - philosophical differences on how to design the software.