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

content/browser/renderer_host/input/mouse_wheel_event_queue.h

Index: content/browser/renderer_host/input/mouse_wheel_event_queue.h
diff --git a/content/browser/renderer_host/input/mouse_wheel_event_queue.h b/content/browser/renderer_host/input/mouse_wheel_event_queue.h
index d4e9c7e97d47bdae55ee764217e55e8e0e714426..9f094d7131e148135e37e26c2433f332e460a508 100644
--- a/content/browser/renderer_host/input/mouse_wheel_event_queue.h
+++ b/content/browser/renderer_host/input/mouse_wheel_event_queue.h
@@ -93,6 +93,10 @@ class CONTENT_EXPORT MouseWheelEventQueue {
   // True if the touchpad and wheel scroll latching is enabled.
   bool enable_scroll_latching_;
 
+  bool enable_async_wheel_events_;

[dtapuska, 2017/06/20 20:53:14]

Could probably use some comments. Looking at the names they seem very similar. I
understand what they do; one is a feature flag. The other is the current state.
But that should be in the code.

[sahel, 2017/06/21 18:09:59]

Done.

+
+  bool send_wheel_events_async_;
+
   blink::WebGestureDevice scrolling_device_;
 
   DISALLOW_COPY_AND_ASSIGN(MouseWheelEventQueue);