Add event ID generator.

Bug: 144889238
Test: atest libinput_test
Change-Id: I0fd192b3c5a08326aa6a6598025c7b8cdc64cce4
Merged-In: I0fd192b3c5a08326aa6a6598025c7b8cdc64cce4
(cherry picked from commit 84b087ec591626e8dd7d3d2c877afb74f0de1b09)
4 files changed