The article mentions a clear criterion for flipping the on-by-default switch: "We’ll also be working on Dynamic Shared Objects (DSOs), a feature that will even

The article mentions a clear criterion for flipping the on-by-default switch: "We’ll also be working on Dynamic Shared Objects (DSOs), a feature that will eventually allow us to provide Application Binary Interface (ABI) stability. [...] Until the ABI becomes stable, Native Client will remain off by default. "