InputTracer: Adjust traced event sensitivity based on allow-list

An allow-list of packages will be defined in the perfetto config for
input traces. We can only allow an event to traced completely (i.e.
treated as a non-sensitive event) if _all_ of the UIDs that the event is
targeting are allow-listed for the trace.

In each trace instace, we maintain a cache of whether UIDs seen so far
are allow-listed. Since the allow-list is specified through a list of
package names, we must query PackageManager through the InputDispatcher
policy to look up the packages that correspond to each UID that we see.

Bug: 210460522
Test: manual with perfetto
Change-Id: I9c19a5ed941ebc239dccc0363cc6553733e16afd
diff --git a/services/inputflinger/tests/InputDispatcher_test.cpp b/services/inputflinger/tests/InputDispatcher_test.cpp
index 9375e92..fcb5ab0 100644
--- a/services/inputflinger/tests/InputDispatcher_test.cpp
+++ b/services/inputflinger/tests/InputDispatcher_test.cpp
@@ -660,6 +660,8 @@
         verify(*mFilteredEvent);
         mFilteredEvent = nullptr;
     }
+
+    gui::Uid getPackageUid(std::string) override { return gui::Uid::INVALID; }
 };
 } // namespace