When in Fullscreen OSX Yosemite won't hide the dock I don't have "auto hide" enable for dock. In all previous version dock, it will hide if I enter in full screen mode for VLC player or for chrome. Now that's no longer the case. 

If I enable "auto hide", then it hides it but that's not what I am looking for as I like to see dock all the time except full screen mode.
Open Terminal and type:

killall Dock


This will restart the process.