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

ui/events/gesture_event_details.h

Index: ui/events/gesture_event_details.h
diff --git a/ui/events/gesture_event_details.h b/ui/events/gesture_event_details.h
index 2b066d56188c5a7ae999492165d8e74b81b8734f..901d9cba5ebaada526491cdb08262d69a66fadd6 100644
--- a/ui/events/gesture_event_details.h
+++ b/ui/events/gesture_event_details.h
@@ -45,6 +45,13 @@ struct EVENTS_BASE_EXPORT GestureEventDetails {
     device_type_ = device_type;
   }
 
+  EventResult source_touch_event_result() const {
+    return source_touch_event_result_;
+  }
+  void set_source_touch_event_result(EventResult result) {
+    source_touch_event_result_ = result;
+  }
+
   int touch_points() const { return touch_points_; }
   void set_touch_points(int touch_points) {
     DCHECK_GT(touch_points, 0);
@@ -225,6 +232,8 @@ struct EVENTS_BASE_EXPORT GestureEventDetails {
 
   GestureDeviceType device_type_;
 
+  EventResult source_touch_event_result_;
+
   int touch_points_;  // Number of active touch points in the gesture.
 
   // Bounding box is an axis-aligned rectangle that contains all the