How to block those annoying "Your device is infected" ads in Chrome without root
Now that you are rooted, you have a host of options and can be free from Google's policy of removing Ad blocking apps from play store

Install Xposed for your Android version and then Adaway to block all ads. remember to keep updating hostfiles periodically


  AdAway is a utility for root users used to help manage hostfile entries. AdAway doesn't directly block ads; it limits unwanted ads by blocking servers that distribute those ads to websites


If you are not familiar with Xposed, Xposed: The mighty Android tool box by Izzy, would be very useful