Some files from Google products (preferably Chrome browser) appearing at random places I have Google Chrome browser installed on My MacBook Air 13". I found few files from Google products in /Library and ~/Library. 


Found com.google.keystone.daemon.plist under /Library/LaunchDaemons/
Found com.google.Chrome.plist and com.google.Keystone.Agent.plist under ~/Library/Preferences/


Don't know why they are there and for what purpose it is used.

Should I delete them? If no, can you tell me reason why. Thanks.
These are google preferences files. They are created outside the program binary because that's how applications should behave on OSX. 

If you delete them, you'll loose your chrome preferences and they will be automatically recreated by Chrome, so no need to delete them.