This prevents the shell user from injecting input as if it were coming
from an existing input device, which in turn makes it easier for malware
/ abuse analysis to detect when someone is injecting input via the
command line vs a real user using a device.
(cherrypick of 95637eb2a332b9a09914b1bf32c10fccfba4a175.)
Bug: 30861057
Test: ran getevent, saw correct output, played with device
Change-Id: Ib53eea1b7767f25510b5d36fe6109101a9fad8e0