My nexus 7 has suddenly started to open Chrome whilst I am reading my newspaper without any input at all from me. It always opens https://www.pubads.g.doubleclick.net etc etc and it has got a bit annoying. I can find lots of suggestions for stopping this on a windows machine but can not find any solution that fits with my Nexus 7 which is running an up to date version of Marshmallow. Can anyone offer me a way to either remove whatever is causing this problem or alternatively to block chrome from visiting this site. Thanks in advance.