Add SYN_DROPPED event handling test for xf86-input-evdev

BUG=chromium-os:35291
TEST=on device; run the platform_EvdevSynDropTest test
  * Execute the test script and see if it passes the test.
     cd /usr/local/autotest
     bin/autotest tests/platform_EvdevSynDropTest/control

Change-Id: Ib5cb219b316f44388e92848420f99d10abb57e2a
Reviewed-on: https://gerrit.chromium.org/gerrit/40317
Reviewed-by: Joseph Shyh-In Hwang <josephsih@chromium.org>
Commit-Queue: Chung-yih Wang <cywang@chromium.org>
Tested-by: Chung-yih Wang <cywang@chromium.org>
19 files changed