Convert input event type to enum class

This will increase type safety and simplify some of the printing.

Bug: 274073185
Test: m checkinput
Change-Id: I848c2f156cc23232c50d2338b4788be3232dba1a
diff --git a/services/inputflinger/Android.bp b/services/inputflinger/Android.bp
index b885435..e04481c 100644
--- a/services/inputflinger/Android.bp
+++ b/services/inputflinger/Android.bp
@@ -213,6 +213,7 @@
     name: "checkinput",
     required: [
         // native targets
+        "libgui_test",
         "libinput",
         "libinputflinger",
         "inputflinger_tests",