Natively. In most cases, faster than the phone version.

There are both ARM and x86 chromebooks, there are both ARM and x86 Android phones. You need to have binaries for both and for Java apps that isn't even an issue. Of course there probably has to be some API translation but usually that isn't particularly slow.

definitely slow farts (it is not emulated, but runs inside a linux container instead, so it won't have that emulation overhead)