Prerendering kicks in as soon as a user begins typing in the URL bar of the browser and Chrome auto-completes a site's address and determines high likelihood that the site is the intended destination. Details about prerendered pages can be monitored in Chrome via the local URL chrome://net-internals/#prerender.
Google also extended the safe browsing features of Chrome and compares executable EXE and MSI files against a whitelist and information about websites that are likely to host malware.
The developer version of Chrome recently went to version 19, concluding the tree of Chrome 18, which will include more than 11,000 changes over Chrome 17. According to Chrome developer Peter Beverloo, Chrome 18 brings six new stable extension APIs, a CSS selector profiler, and mutation observers.
Chrome 17 can be downloaded here.