Do not use RefBase in EventHub

Switch to std::unique_ptr instead.
Unfortunately, have to also switch to shared_ptr because FakeEventHub
implements EventHub but is also used to inject events when testing
InputReader.

Bug: 117684064
Test: atest inputflinger_tests
Change-Id: I789ba0ca255b6a1f179711c61fc9da98a3c6a800
5 files changed