TouchpadInputMapper: add timer provider

Adding a timer provider allows the Gestures library to perform some
asynchronous tasks, including ones which improve tap-to-click detection.

Bug: 297192727
Test: set the
      persist.device_config.aconfig_flags.input.com.android.input.flags.enable_gestures_library_timer_provider
      sysprop to true, restart, then make fast tap-to-click gestures
      (where the finger is contacting for fewer than 3 frames) on the
      touchpad, and check they're reported immediately
Change-Id: Ib9b8dacc71c88b6fd47bdd747f90ef6a44b37cc4
diff --git a/libs/input/input_flags.aconfig b/libs/input/input_flags.aconfig
index 2af5a4a..a0563f9 100644
--- a/libs/input/input_flags.aconfig
+++ b/libs/input/input_flags.aconfig
@@ -20,3 +20,10 @@
   description: "Set to true to enable PointerChoreographer: the new pipeline for showing pointer icons"
   bug: "293587049"
 }
+
+flag {
+  name: "enable_gestures_library_timer_provider"
+  namespace: "input"
+  description: "Set to true to enable timer support for the touchpad Gestures library"
+  bug: "297192727"
+}