So I downloaded, installed, and inserted into path the clang formatting plugin. I also tested it and it works for Google (Mozilla, etc.) formatting options out of the box, y
For the record, it seems that if both "Fallback Style" and "Style" are set to "file", no formatting will happen even if the style file is at its correct location. Setting "Fallback Style" to something different than "file" (e.g. "none") helps.