[lukegb]

According to the first post in the linked thread, the switch to clang is transparent enough that the VS IDE-based debugging experience still works.

My guess (not being a Chromium developer myself) is that this is an exercise in consistency across platforms - I can imagine that using the same compiler on all supported platforms makes the language features supported consistent and removes the risk of one compiler generating much worse output for the same code. But I'm just postulating, I don't actually know for sure.