Any app can be easily locked into RAM via
the little lock icon in the Overview carousel, which will keep them from being cleared during either of these recent app management tasks.
Thankfully, more and more sites are using HTTPS by default these days, so you shouldn't have to do much — just make sure you see
that little lock icon when you connect to any site that requires a password or credit card information.
Not exact matches
While this puts you into Android's Security menu, it doesn't put you directly into the menu where the required setting toggle is — for that, you'll have to tap that
little cog
icon next to the «Screen
lock» entry.