Delay Input.dispatchKeyEvent response until after key event ack.

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 0ce169540b3cae2c0e67d865f585d0d48d8763a3..463dc19a1167705b728564556991fbb3264f6724 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -1954,6 +1954,8 @@ void RenderWidgetHostImpl::OnKeyboardEventAck(
       const NativeWebKeyboardEventWithLatencyInfo& event,
       InputEventAckState ack_result) {
   latency_tracker_.OnInputEventAck(event.event, &event.latency, ack_result);
+  FOR_EACH_OBSERVER(InputEventObserver, input_event_observers_,
+                    OnInputEventAck(event.event, event.event.is_synthetic));
 
   const bool processed = (INPUT_EVENT_ACK_STATE_CONSUMED == ack_result);
 
@@ -1974,6 +1976,9 @@ void RenderWidgetHostImpl::OnMouseEventAck(
     InputEventAckState ack_result) {
   latency_tracker_.OnInputEventAck(mouse_event.event, &mouse_event.latency,
                                    ack_result);
+  // TOOD(samuong): keep track of synthetic mouse events
+  FOR_EACH_OBSERVER(InputEventObserver, input_event_observers_,
+                    OnInputEventAck(mouse_event.event, true));

[samuong, 2016/10/20 23:36:18]

Right now I'm setting is_synthetic to true for *all* mouse events. Unlike key
events, there is no content-level NativeWebMouseEvent, only the blink-level
WebMouseEvent. So there's a few options here:

1. add blink::WebMouseEvent::is_synthetic
2. create content::NativeWebMouseEvent and add an is_synthetic property
3. forget about this, since we don't really support the use case where we mix
synthetic and user inputs anyway

Can you let me know what you think here?

 }
 
 void RenderWidgetHostImpl::OnWheelEventAck(
@@ -1981,6 +1986,8 @@ void RenderWidgetHostImpl::OnWheelEventAck(
     InputEventAckState ack_result) {
   latency_tracker_.OnInputEventAck(wheel_event.event, &wheel_event.latency,
                                    ack_result);
+  FOR_EACH_OBSERVER(InputEventObserver, input_event_observers_,
+                    OnInputEventAck(wheel_event.event, false));
 
   if (!is_hidden() && view_) {
     if (ack_result != INPUT_EVENT_ACK_STATE_CONSUMED &&
@@ -1995,6 +2002,8 @@ void RenderWidgetHostImpl::OnGestureEventAck(
     const GestureEventWithLatencyInfo& event,
     InputEventAckState ack_result) {
   latency_tracker_.OnInputEventAck(event.event, &event.latency, ack_result);
+  FOR_EACH_OBSERVER(InputEventObserver, input_event_observers_,
+                    OnInputEventAck(event.event, false));
 
   if (view_)
     view_->GestureEventAck(event.event, ack_result);
@@ -2004,6 +2013,8 @@ void RenderWidgetHostImpl::OnTouchEventAck(
     const TouchEventWithLatencyInfo& event,
     InputEventAckState ack_result) {
   latency_tracker_.OnInputEventAck(event.event, &event.latency, ack_result);
+  FOR_EACH_OBSERVER(InputEventObserver, input_event_observers_,
+                    OnInputEventAck(event.event, false));
 
   if (touch_emulator_ &&
       touch_emulator_->HandleTouchEventAck(event.event, ack_result)) {