Async Wheel Event with only the first one cancellable behind a flag.

ui/events/blink/blink_event_util.cc

Index: ui/events/blink/blink_event_util.cc
diff --git a/ui/events/blink/blink_event_util.cc b/ui/events/blink/blink_event_util.cc
index 7dfbe2912ecc587df6f6949babb5096d4911ac07..e1ba7639d0280e749c555364e8435c2338816410 100644
--- a/ui/events/blink/blink_event_util.cc
+++ b/ui/events/blink/blink_event_util.cc
@@ -263,7 +263,8 @@ bool CanCoalesce(const WebMouseWheelEvent& event_to_coalesce,
          event.momentum_phase == event_to_coalesce.momentum_phase &&
          event.resending_plugin_id == event_to_coalesce.resending_plugin_id &&
          event.has_precise_scrolling_deltas ==
-             event_to_coalesce.has_precise_scrolling_deltas;
+             event_to_coalesce.has_precise_scrolling_deltas &&
+         event.dispatch_type == event_to_coalesce.dispatch_type;

[dtapuska, 2017/06/16 17:36:09]

This seems wrong.

For touch we allow a cancellable touch move to be coalesced with a
non-cancellable one. 

I think the preferred solution is something like:
https://cs.chromium.org/chromium/src/ui/events/blink/blink_event_util.cc?l=344

[sahel, 2017/06/20 19:22:33]

Done.

 }
 
 void Coalesce(const WebMouseWheelEvent& event_to_coalesce,