InputTracer: Track inbound events

Track whether an event is an inbound event or a synthesized event. Then
read the config flags from the perfetto backend, and decide whether to
ignore events in the trace depending on the flags that are enabled.

Bug: 210460522
Test: manual with perfetto
Change-Id: I665644f026fca4ab823221656c7b519893e2a1eb
4 files changed