One of our core security principles is, "Design for defense in depth." Some of the things we've done or are working on to live up to this principle include:

• Chrome on Windows (sandbox) design and implementation and the Sandboxing FAQ (mostly Windows specific)
• Chrome on Linux and Chrome OS (sandbox) overview (including the most current seccomp-bpf layer)
• Chrome on OSX (sandbox) overview and the second-layer bootstrap sandbox

Plugin sandboxing

• Flash sandboxing (PPAPI)

Site Isolation

We're currently working on using Chrome's sandbox to isolate websites from each other via the Site Isolation project, which will help to mitigate cross-site information leaks (among other threats) in the presence of a vulnerability in the renderer process.