Refactor compositor event handling path to be callback-based

blimp/client/feature/compositor/blimp_input_handler_wrapper.cc

Index: blimp/client/feature/compositor/blimp_input_handler_wrapper.cc
diff --git a/blimp/client/feature/compositor/blimp_input_handler_wrapper.cc b/blimp/client/feature/compositor/blimp_input_handler_wrapper.cc
index 9f24ec8590cdd32d1d1ee371dd46f6bff30ffbe3..9bf60ee12967fb6aa70b27492ef00261c4505f3a 100644
--- a/blimp/client/feature/compositor/blimp_input_handler_wrapper.cc
+++ b/blimp/client/feature/compositor/blimp_input_handler_wrapper.cc
@@ -93,7 +93,8 @@ void BlimpInputHandlerWrapper::DidOverscroll(
     const gfx::Vector2dF& accumulated_overscroll,
     const gfx::Vector2dF& latest_overscroll_delta,
     const gfx::Vector2dF& current_fling_velocity,
-    const gfx::PointF& causal_event_viewport_point) {
+    const gfx::PointF& causal_event_viewport_point,
+    bool bundle_ack_with_triggering_event) {
   DCHECK(compositor_thread_checker_.CalledOnValidThread());
 }