Replace "showkey" with client autotest

FAFTSetup, ECLidSwitch, and ECPowerButton all rely on
the showkey utility which doesn't run on freon.  So,
this change adds a client side autotest that reads
evdev input and verifies it matches the passed in
expected output, and then modifies each of the
aforementioned tests to invoke the client side test

TEST=run FAFTSetup on Peppy with servo and verify that
the correct keys sent pass, incorrect keys sent fail
with "Keys mismatched" and no keys sent fail with
"No keys pressed"

Change-Id: I3b667a91b7f2ed84a6e91460f554d53a857a1373
Tested-by: danny chan <>
Reviewed-by: danny chan <>
Reviewed-by: David Sodman <>
Commit-Queue: danny chan <>
(cherry picked from commit 3ad5164cfaa536b2f71a9098545c39d10ad74cd7)
Reviewed-by: Bernie Thompson <>
Commit-Queue: Bernie Thompson <>
6 files changed