[mac-chaffee]

The encryption Chrome uses isn't just some key on disk that can be scooped up. On macOS at least, it's stored in the secure enclave which only signed Chrome binaries can access.

Now all this is pointless due to Chrome allowing remote debugging, but Firefox could come along and do it right and it would actually be an increase in security. A random unsandboxed binary trying to access the key would be blocked by the kernel.