This app was mentioned in 1 comment, with an average of 1.00 upvote
You mentioned browsing without an external app, so you may not be interested, but this is what I use:
https://play.google.com/store/apps/details?id=halverson.gregory.reverseimagesearch
Share an image and choose "Search Image on Google", and away you go!
Edit: Oh, it doesn't seem to work in rif, though. I only see an option to share the image URL, not the image itself.