[VSync Queue] Plug touch ack to gesture events and flush vsync queue if necessary

ui/events/event_constants.h

Index: ui/events/event_constants.h
diff --git a/ui/events/event_constants.h b/ui/events/event_constants.h
index c7736622783d2335da227a73f470beeaa3012a38..0fe2f7b8a69cca9dba3980525e7b1e0cad71e91b 100644
--- a/ui/events/event_constants.h
+++ b/ui/events/event_constants.h
@@ -153,6 +153,9 @@ enum EventResult {
                // happens if the event is being handled
                // asynchronously, or if the event is invalid and
                // shouldn't be handled at all.
+  ER_IGNORED_NON_BLOCKING =

[dtapuska, 2017/05/25 15:40:12]

The name is slightly confusing because this is a bit set.

sadrul@ might have a comment here.

+      1 << 3,  // The event was dispatched non-blocking, a synthetic ack has
+               // been received.
 };
 
 // Phase of the event dispatch.