A report from 9to5Google points at a new commit posted to Chromium’s Gerrit source code management which reveals that this is a new feature that seems to be in the works. For the most part it seems that this will more or less do the same thing as what Safari does on iOS devices, so if you’re familiar with that feature then this shouldn’t be anything too radically different.
That being said, 9to5Google points out that Google probably needs to test out this feature really well simply because these swiping gestures can sometimes be mistaken. For example some websites might have image galleries that require users to swipe to navigate them, so by making the feature too sensitive, users might accidentally end up swiping forwards or back instead of swiping through the gallery as intended.
No word on when the feature is expected to make its way onto Chrome for Android, but since it seems that this is a fairly new work in progress, maybe we shouldn’t expect to see it anytime soon.