Many photographers don’t realize it but Google Plus has always had RAW conversion. Most people would run out of space with a memory card’s worth of RAW images so I’d imagine the only people taking advantage are those paying for the extra storage space.
Google just updated their RAW system using new algorithms created by their Nik Photography team (formerly Nik Software). They have also added more cameras to their supported list.
I personally do not see many photographers allowing Google Plus to convert their photographs but you then again one never knows and everyone has their own methods.