I was just having this same problem. It hadn't been doing this until recently, but also recently I downloaded a torrent file which was actually malicious. I've been going through my computer cleaning out files, and noticed something called lavasoft- web companion. It was an adware program that disguised itself as a browser help software. I was able to forcefully remove it, and immediately after noticed the google chrome processes stopped running. I would recommend doing a clean sweep of your computer with an anti-virus software, check your control panel > Programs > Programs and features > uninstall a program, and look for any unusual programs that you did not install or you may not need. IF you come across a program that refuses to uninstall or may seem like an infectious file, google it and find a way to safely remove it. Google chrome, when opened by the user should never utilize large amounts of CPU, unless you are using a severely outdated PC. So if this continues to happen you have some malicious program taking over your application, forcing it to run processes to gain information on your browsing history and style, and is more than likely gaining data from you.