Use TWO_FINGER_SWIPE classification for touchpad scroll events

This allows apps to distinguish the fake finger created for touchpad
scrolling from an actual finger.

Bug: 246758376
Test: add classification to InputDispatcher's outbound event logs and
      check the new value is used when scrolling
Change-Id: Ia90f9984e75ad6fde2d0e42628ab42eab371b7a5
diff --git a/include/input/Input.h b/include/input/Input.h
index 2dd651e..172e5b4 100644
--- a/include/input/Input.h
+++ b/include/input/Input.h
@@ -289,6 +289,10 @@
      * The current gesture likely represents a user intentionally exerting force on the touchscreen.
      */
     DEEP_PRESS = AMOTION_EVENT_CLASSIFICATION_DEEP_PRESS,
+    /**
+     * The current gesture represents the user swiping with two fingers on a touchpad.
+     */
+    TWO_FINGER_SWIPE = AMOTION_EVENT_CLASSIFICATION_TWO_FINGER_SWIPE,
 };
 
 /**