Google engineers are developing a 'back/forward cache' to reduce the latency with which Chrome returns to a previous page, or goes forward from one. This involves saving an entire webpage in memory, JavaScript included. While this may enhance the browser's UX, it also implies privacy issues.
https://www.notebookcheck.net/Chrome-developers-are-preparing-a-new-feature-to-make-back-forward-navigation-faster.410979.0.html