[roll] Roll fuchsia [scenic][ui-input] Refactor GestureArena

Attempts to make GestureArena a bit more readable by splitting
up methods and streamlining function calls.

No functional changes expected.

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/696232
Original-Revision: affb994955bcc2d54795d8dde562b5445ed86d73
GitOrigin-RevId: d4923dec333edd72f4415946b48695ff11f7a878
Change-Id: Ie2e83b0200a7578b9ca153cada99657b55971e57
diff --git a/stem b/stem
index 7a6fbaf..7494fe8 100644
--- a/stem
+++ b/stem
@@ -10,7 +10,7 @@
              githooks=""
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="1e2ffc6c7232dfd9d9e92dc22a535048f373a019"/>
+             revision="affb994955bcc2d54795d8dde562b5445ed86d73"/>
   </projects>
   <hooks>
     <hook name="install-environment"